The Ottawa Statement implementation guidance document for cluster randomized trials in the hemodialysis setting.

Research teams are increasingly interested in using cluster randomized trial (CRT) designs to generate practice-guiding evidence for in-center maintenance hemodialysis. However, CRTs raise complex ethical issues. The Ottawa Statement on the Ethical Design and Conduct of Cluster Randomized Trials, published in 2012, provides 15 recommendations to address ethical issues arising within 7 domains: justifying the CRT design, research ethics committee review, identifying research participants, obtaining informed consent, gatekeepers, assessing benefits and harms, and protecting vulnerable participants. But applying the Ottawa Statement recommendations to CRTs in the hemodialysis setting is complicated by the unique features of the setting and population. Here, with the help of content experts and patient partners, we co-developed this implementation guidance document to provide research teams, research ethics committees, and other stakeholders with detailed guidance on how to apply the Ottawa Statement recommendations to CRTs in the hemodialysis setting, the result of a 4-year research project. Thus, our work demonstrates how the voices of patients, caregivers, and all stakeholders may be included in the development of research ethics guidance.

Incidence of Total Knee Arthroplasty After Arthroscopic Surgery for Knee Osteoarthritis: A Secondary Analysis of a Randomized Clinical Trial.

Importance: It is unclear whether arthroscopic resection of degenerative knee tissues among patients with osteoarthritis (OA) of the knee delays or hastens total knee arthroplasty (TKA); opposite findings have been reported. Objective: To compare the long-term incidence of TKA in patients with OA of the knee after nonoperative management with or without additional arthroscopic surgery. Design, Setting, and Participants: In this ad hoc secondary analysis of a single-center, assessor-blinded randomized clinical trial performed from January 1, 1999, to August 31, 2007, 178 patients were followed up through March 31, 2019. Participants included adults diagnosed with OA of the knee referred for potential arthroscopic surgery in a tertiary care center specializing in orthopedics in London, Ontario, Canada. All participants from the original randomized clinical trial were included. Data were analyzed from June 1, 2021, to October 20, 2022. Exposures: Arthroscopic surgery (resection or debridement of degenerative tears of the menisci, fragments of articular cartilage, or chondral flaps and osteophytes that prevented full extension) plus nonoperative management (physical therapy plus medications as required) compared with nonoperative management only (control). Main Outcomes and Measures: Total knee arthroplasty was identified by linking the randomized trial data with prospectively collected Canadian health administrative datasets where participants were followed up for a maximum of 20 years. Multivariable Cox proportional hazards regression models were used to compare the incidence of TKA between intervention groups. Results: A total of 178 of 277 eligible patients (64.3%; 112 [62.9%] female; mean [SD] age, 59.0 [10.0] years) were included. The mean (SD) body mass index was 31.0 (6.5). With a median follow-up of 13.8 (IQR, 8.4-16.8) years, 31 of 92 patients (33.7%) in the arthroscopic surgery group vs 36 of 86 (41.9%) in the control group underwent TKA (adjusted hazard ratio [HR], 0.85 [95% CI, 0.52-1.40]). Results were similar when accounting for crossovers to arthroscopic surgery (13 of 86 [15.1%]) during follow-up (HR, 0.88 [95% CI, 0.53-1.44]). Within 5 years, the cumulative incidence was 10.2% vs 9.3% in the arthroscopic surgery group and control group, respectively (time-stratified HR for 0-5 years, 1.06 [95% CI, 0.41-2.75]); within 10 years, the cumulative incidence was 23.3% vs 21.4%, respectively (time-stratified HR for 5-10 years, 1.06 [95% CI, 0.45-2.51]). Sensitivity analyses yielded consistent results. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial of arthroscopic surgery for patients with OA of the knee, a statistically significant association with delaying or hastening TKA was not identified. Approximately 80% of patients did not undergo TKA within 10 years of nonoperative management with or without additional knee arthroscopic surgery. Trial Registration: ClinicalTrials.gov Identifier: NCT00158431.

Impact of the 2021 CKD-EPI eGFR Equation on Kidney Care Referral Criteria in Ontario, Canada: A Population-based Cross-sectional Study.

Background: In some jurisdictions, individuals become eligible or recommended for referral for different types of kidney care using criteria based on their estimated glomerular filtration rate (eGFR). Historically, GFR was estimated with an equation developed in 2009, which included a Black race term. An updated, race-free equation was developed in 2021. It is unclear how adoption of the 2021 equation will influence the number of individuals meeting referral criteria to receive different types of kidney care. Objective: To develop population-based estimates on how the number of individuals meeting the eGFR-based referral criteria to receive three different types of kidney care (nephrologist consultation, care in a multi-care specialty clinic, kidney transplant evaluation) changes when the 2021 versus 2009 equation is used to calculate eGFR. Design: Population-based, cross-sectional study. Setting: Ontario, Canada's most populous province with 14.2 million residents as of 2021. Less than 5% of Ontario's residents self-identify as being of Black race. Patients: Adults with at least one outpatient serum creatinine measurement in the 2 years prior to December 31, 2021. Measurements: Referral criteria to 3 different types of kidney care: nephrologist consultation, multi-care specialty clinic, and evaluation for a kidney transplant. The eGFR thresholds used to define referral eligibility or recommendation for these kidney health services were based on guidelines from Ontario's provincial renal agency. Methods: The number of individuals meeting referral criteria for the 3 different healthcare services was compared between the 2009 and 2021 equations, restricted to individuals not yet receiving that level of care. As individual-level race data were not available, estimates were repeated, randomly assigning a Black race status to 1%, 5%, and 10% of the population. Results: We had an outpatient serum creatinine measurement available for 1 048 110 adults. Using the 2009 equation, 37 345 individuals met the criteria to be referred to a nephrologist, 10 019 met the criteria to receive care in a multi-care specialty clinic, and 10 178 met the criteria to be referred for kidney transplant evaluation. Corresponding numbers with the 2021 equation (and the percent relative to the 2009 equation) were 26 645 (71.3%), 9009 (89.9%), and 8615 (84.6%) individuals, respectively. These numbers were largely unchanged when Black race was assumed in up to 10% of the population. Limitations: Referral criteria based solely on urine albumin-to-creatinine ratio were not assessed. Self-reported race data were unavailable. Conclusions: For healthcare planning, in regions where a minority of the population is Black, a substantial number of individuals may no longer meet referral criteria for different types of kidney healthcare following adoption of the new 2021 eGFR equation.

Contexte: Dans certaines régions, les individus sont dirigés vers différents types de soins rénaux, ou y deviennent admissibles, selon des critères fondés sur le débit de filtration glomérulaire estimé (DFGe). Historiquement, le DFG était estimé avec une équation développée en 2009 comportant un terme qui tenait compte du fait d'être une personne de race noire. Une nouvelle équation sans mention de la race a été développée en 2021. Il est difficile de savoir comment l'adoption de l'équation de 2021 influencera le nombre de personnes qui répondront aux critères pour recevoir divers types de soins rénaux. Objectifs: Établir des estimations populationnelles de la variation du nombre de personnes qui répondent aux critères d'orientation fondés sur le DFGe pour recevoir trois différents types de soins rénaux (consultation avec un néphrologue, soins dans une clinique multidisciplinaire spécialisée, évaluation pour une transplantation rénale) selon que le DFGe est calculé avec l'équation de 2021 ou de 2009. Conception: Étude populationnelle transversale rétrospective. Cadre: L'Ontario, la province la plus peuplée du Canada avec 14,2 millions d'habitants en 2021. Moins de 5 % des résidents de l'Ontario s'identifient comme étant de race noire. Sujets: Des adultes avec au moins une mesure de la créatinine sérique en ambulatoire au cours des deux ans précédant le 31 décembre 2021. Mesures: Les critères d'orientation vers trois différents types de soins rénaux : consultation avec un néphrologue, soins en clinique multidisciplinaire spécialisée et évaluation pour une transplantation rénale. Les seuils de DFGe utilisés pour définir l'admissibilité à ­ ou l'orientation vers ­ ces services de santé rénale étaient fondés sur les lignes directrices de l'agence provinciale de soins rénaux de l'Ontario. Méthodologie: On a comparé les nombres d'individus répondant aux critères d'orientation pour les trois différents services de santé, calculés avec les équations de 2009 et de 2021, en se limitant aux personnes qui ne recevaient pas encore de tels soins. Les données individuelles sur la race n'étant pas disponibles, les estimations ont été répétées en attribuant aléatoirement un statut de race noire à 1 %, à 5 % et à 10 % de la population étudiée. Résultats: Une mesure de la créatinine sérique en ambulatoire était disponible pour un total de 1 048 110 adultes. Avec l'équation de 2009, 37 345 personnes répondaient aux critères pour être dirigées vers un néphrologue, 10 019 répondaient aux critères pour recevoir des soins dans une clinique multidisciplinaire spécialisée et 10 178 répondaient aux critères pour être évaluées pour une transplantation rénale. Avec l'équation de 2021, ces mêmes nombres de personnes (pourcentage par rapport à l'équation de 2009) étaient respectivement 26 645 (71,3 %), 9 009 (89,9 %) et 8 615 (84,6 %). Des chiffres qui sont demeurés majoritairement inchangés même en assumant une proportion de jusqu'à 10 % de personnes de race noire dans la population. Limites: Les critères d'orientation fondés uniquement sur le rapport albumine/créatinine urinaire n'ont pas été évalués. Les données autodéclarées sur la race n'étaient pas disponibles. Conclusion: Pour la planification des soins de santé, dans les régions où une minorité de la population est noire, un nombre important de personnes pourraient ne plus répondre aux critères d'orientation vers différents types de soins rénaux après l'adoption de l'équation de 2021 pour le calcul du DFGe.

Effectiveness of a Fourth COVID-19 mRNA Vaccine Dose Against the Omicron Variant in Solid Organ Transplant Recipients.

BACKGROUND: The effectiveness of booster doses of COVID-19 vaccines in solid organ transplant recipients is unclear. We conducted a population-based matched cohort study using linked administrative healthcare databases from Ontario, Canada to estimate the marginal vaccine effectiveness of a fourth versus third dose of the BNT162b2 and mRNA-1273 vaccines against clinically important outcomes (ie, hospitalization or death) and infection during the era of the Omicron variant. METHODS: We matched 3120 solid organ transplant recipients with a third COVID-19 vaccine dose (reference) to 3120 recipients with a fourth dose. Recipients were matched on the third dose date (±7 d). We used a multivariable Cox proportional hazards model to estimate the marginal vaccine effectiveness with outcomes occurring between December 21, 2021 and April 30, 2022. RESULTS: The cumulative incidence of COVID-19-related hospitalization or death was 2.8% (95% confidence interval [CI], 2.0-3.7) in the third dose group compared with 1.1% (95% CI, 0.59-1.8) in the fourth dose group after 84 d of follow-up (P < 0.001). The adjusted marginal vaccine effectiveness was 70% (95% CI, 47-83) against clinically important outcomes and 39% (95% CI, 21-52) against SARS-CoV-2 infection. CONCLUSIONS: Compared with a third dose, a fourth dose of the COVID-19 vaccine was associated with improved protection against hospitalization, death, and SARS-CoV-2 infection during the Omicron era. Results highlight the importance of a booster COVID-19 vaccine dose in solid organ transplant recipients.

Effect of a Novel Multicomponent Intervention to Improve Patient Access to Kidney Transplant and Living Kidney Donation: The EnAKT LKD Cluster Randomized Clinical Trial.

Importance: Patients with advanced chronic kidney disease (CKD) have the best chance for a longer and healthier life if they receive a kidney transplant. However, many barriers prevent patients from receiving a transplant. Objectives: To evaluate the effect of a multicomponent intervention designed to target several barriers that prevent eligible patients from completing key steps toward receiving a kidney transplant. Design, Setting, and Participants: This pragmatic, 2-arm, parallel-group, open-label, registry-based, superiority, cluster randomized clinical trial included all 26 CKD programs in Ontario, Canada, from November 1, 2017, to December 31, 2021. These programs provide care for patients with advanced CKD (patients approaching the need for dialysis or receiving maintenance dialysis). Interventions: Using stratified, covariate-constrained randomization, allocation of the CKD programs at a 1:1 ratio was used to compare the multicomponent intervention vs usual care for 4.2 years. The intervention had 4 main components, (1) administrative support to establish local quality improvement teams; (2) transplant educational resources; (3) an initiative for transplant recipients and living donors to share stories and experiences; and (4) program-level performance reports and oversight by administrative leaders. Main Outcomes and Measures: The primary outcome was the rate of steps completed toward receiving a kidney transplant. Each patient could complete up to 4 steps: step 1, referred to a transplant center for evaluation; step 2, had a potential living donor contact a transplant center for evaluation; step 3, added to the deceased donor waitlist; and step 4, received a transplant from a living or deceased donor. Results: The 26 CKD programs (13 intervention, 13 usual care) during the trial period included 20 375 potentially transplant-eligible patients with advanced CKD (intervention group [n = 9780 patients], usual-care group [n = 10 595 patients]). Despite evidence of intervention uptake, the step completion rate did not significantly differ between the intervention vs usual-care groups: 5334 vs 5638 steps; 24.8 vs 24.1 steps per 100 patient-years; adjusted hazard ratio, 1.00 (95% CI, 0.87-1.15). Conclusions and Relevance: This novel multicomponent intervention did not significantly increase the rate of completed steps toward receiving a kidney transplant. Improving access to transplantation remains a global priority that requires substantial effort. Trial Registration: ClinicalTrials.gov Identifier: NCT03329521.

Variation in Kidney Transplant Referral Across Chronic Kidney Disease Programs in Ontario, Canada.

Background: Eligible patients with kidney failure should have equal access to kidney transplantation. Transplant referral is the first crucial step toward receiving a kidney transplant; however, studies suggest substantial variation in the rate of kidney transplant referral across regions. The province of Ontario, Canada, has a public, single-payer health care system with 27 regional chronic kidney disease (CKD) programs. The probability of being referred for kidney transplant may not be equal across CKD programs. Objective: To determine whether there is variability in kidney transplant referral rates across Ontario's CKD programs. Design: Population-based cohort study using linked administrative health care databases from January 1, 2013, to November 1, 2016. Setting: Twenty-seven regional CKD programs in the province of Ontario, Canada. Patients: Patients approaching the need for dialysis (advanced CKD) and patients receiving maintenance dialysis (maximum follow-up: November 1, 2017). Measurements: Kidney transplant referral. Methods: We calculated the 1-year unadjusted cumulative probability of kidney transplant referral for Ontario's 27 CKD programs using the complement of Kaplan-Meier estimator. We calculated standardized referral ratios (SRRs) for each CKD program, using expected referrals from a 2-staged Cox proportional hazards model, adjusting for patient characteristics in the first stage. Standardized referral ratios with a value less than 1 were below the provincial average (maximum possible follow-up of 4 years 10 months). In an additional analysis, we grouped CKD programs according to 5 geographic regions. Results: Among 8641 patients with advanced CKD, the 1-year cumulative probability of kidney transplant referral ranged from 0.9% (95% confidence interval [CI]: 0.2%-3.7%) to 21.0% (95% CI: 17.5%-25.2%) across the 27 CKD programs. The adjusted SRR ranged from 0.2 (95% CI: 0.1-0.4) to 4.2 (95% CI: 2.1-7.5). Among 6852 patients receiving maintenance dialysis, the 1-year cumulative probability of transplant referral ranged from 6.4% (95% CI: 4.0%-10.2%) to 34.5% (95% CI: 29.5%-40.1%) across CKD programs. The adjusted SRR ranged from 0.2 (95% CI: 0.1-0.3) to 1.8 (95% CI: 1.6-2.1). When we grouped CKD programs according to geographic region, we found that patients residing in Northern regions had a substantially lower 1-year cumulative probability of transplant referral. Limitations: Our cumulative probability estimates only captured referrals within the first year of advanced CKD or maintenance dialysis initiation. Conclusions: There is marked variability in the probability of kidney transplant referral across CKD programs operating in a publicly funded health care system.

Contexte: Les patients atteints d'insuffisance rénale qui y sont admissibles devraient bénéficier d'un accès égal à la transplantation rénale. L'aiguillage vers un programme de transplantation est la première étape essentielle pour recevoir une greffe de rein. Des études suggèrent cependant qu'il existe des variations substantielles dans les taux d'aiguillage vers une greffe de rein selon les régions. La province de l'Ontario, au Canada, dispose d'un système public de santé à payeur unique comptant 27 programmes régionaux d'insuffisance rénale chronique (IRC). La probabilité d'être aiguillé vers une transplantation rénale n'est pas forcément la même dans tous les programmes d'IRC. Objectif: Déterminer s'il existe une variabilité dans les programmes d'IRC de l'Ontario en ce qui concerne les taux d'aiguillage vers une greffe de rein. Conception: Étude de cohorte représentative d'une population réalisée en Ontario (Canada) entre le 1er janvier 2013 et le 1er novembre 2016 à partir des données administratives en santé. Cadre: Les 27 programmes régionaux d'IRC de la province de l'Ontario (Canada). Sujets: Des patients approchant le besoin de dialyse (IRC de stade avancé) et des patients recevant des traitements de dialyse d'entretien (suivi maximum jusqu'au 1er novembre 2017). Mesures: L'aiguillage vers une greffe de rein. Méthodologie: Nous avons calculé la probabilité cumulative non ajustée d'être aiguillé à l'intérieur d'un an vers une transplantation rénale dans chacun des 27 programmes d'IRC de l'Ontario en utilisant le complément de l'estimateur Kaplan-Meier. Nous avons calculé les ratios d'aiguillage normalisés (SRR­Standardized Reference Ratios) des programmes d'IRC en utilisant les taux d'aiguillge attendus à partir d'un modèle de risques proportionnels de Cox en deux étapes, avec correction en fonction des caractéristiques du patient dans la première étape. Les ratios d'aiguillage normalisés d'une valeur inférieure à 1 étaient inférieurs à la moyenne provinciale (suivi maximum possible de 4 ans et 10 mois). Dans une analyse supplémentaire, nous avons regroupé les programmes d'IRC selon cinq régions géographiques. Résultats: Parmi les 8 641 patients atteints d'IRC de stade avancé, la probabilité cumulative d'aiguillage en un an pour une transplantation rénale variait de 0,9 % (IC 95 %: 0,2-3,7 %) à 21,0 % (IC 95 %: 17,5-25,2 %) pour l'ensemble des 27 programmes d'IRC. Le SRR corrigé variait de 0,2 (IC à 95 %: 0,1-0,4) à 4,2 (IC 95 %: 2,1-7,5). Parmi les 6 852 patients qui recevaient une dialyse d'entretien, la probabilité cumulative d'aiguillage en un an vers la transplantation variait de 6,4 % (IC 95 %: 4,0-10,2 %) à 34,5 % (IC 95 %: 29,5-40,1 %) pour l'ensemble des programmes d'IRC. Le SRR corrigé variait de 0,2 (IC 95 %: 0,1-0,3) à 1,8 (IC 95 %: 1,6-2,1). En regroupant les programmes d'IRC en fonction de la région géographique, nous avons constaté que les patients résidant dans les régions du Nord avaient une probabilité cumulative nettement plus faible d'être aiguillés vers la transplantation en un an. Limites: Nos estimations de la probabilité cumulative n'ont permis de saisir que les aiguillages au cours de la première année d'IRC de stade avancé ou de l'amorce d'une dialyse d'entretien. Conclusion: Il existe une variabilité marquée dans la probabilité d'être aiguillé vers une transplantation rénale dans les programmes d'IRC opérant dans un système de santé financé par l'État.

Health Services Use and Outcomes for Hospital Admissions With a Major Cardiovascular Event Recorded in Health Care Administrative Data in Patients Receiving Maintenance Hemodialysis: A Retrospective Cohort Study.

Background: Administrative data are used in studies of hemodialysis care to report cardiovascular-related hospitalizations. Showing recorded events are associated with significant health care resource use and poor outcomes would confirm that administrative data algorithms identify clinically meaningful events. Objective: The objective of this study was to describe the 30-day health service use and outcomes when a hospital admission with myocardial infarction, congestive heart failure, or ischemic stroke is recorded in administrative databases. Design: This is a retrospective review of linked administrative data. Patients and Setting: Patients receiving maintenance in-center hemodialysis in Ontario, Canada, between April 1, 2013, and March 31, 2017, were included. Measurements: Records from linked health care databases at ICES in Ontario, Canada were considered. We identified hospital admission with the most responsible diagnosis recorded as myocardial infarction, congestive heart failure, or ischemic stroke. We then assessed the frequency of common tests, procedures, consultations, post-discharge outpatient drug prescriptions, and outcomes within 30 days following the hospital admission. Methods: We used descriptive statistics to summarize results using counts and percentages for categorical variables and means with standard deviations or medians with quartile ranges for continuous variables. Results: There were 14 368 patients who received maintenance hemodialysis between April 1, 2013, and March 31, 2017. The number of events per 1000 person-years was 33.5 for hospital admissions with myocardial infarction, 34.2 for congestive heart failure, and 12.9 for ischemic stroke. The median (25th, 75th percentile) duration of hospital stay was 5 (3-10) days for myocardial infarction, 4 (2-8) days for congestive heart failure, and 9 (4-18) days for ischemic stroke. The chance of death within 30 days was 21% for myocardial infarction, 11% for congestive heart failure, and 19% for ischemic stroke. Limitations: Events, procedures, and tests recorded in administrative data can be misclassified compared with medical charts. Conclusions: In patients receiving maintenance hemodialysis, hospital admissions of major cardiovascular events routinely recorded in health administrative databases are associated with significant use of health service resources and poor health outcomes.

Contexte: Les données administratives sont utilisées pour signaler les hospitalisations liées aux maladies cardiovasculaires dans les études portant sur les soins en hémodialyse. Montrer que les événements signalés sont associés à une utilisation importante des ressources en santé et à une évolution défavorable confirmerait que les algorithmes de données administratives identifient les événements cliniquement significatifs. Objectif: Décrire les interventions et l'évolution de l'état de santé sur une période de 30 jours lorsqu'une hospitalisation pour infarctus du myocarde, insuffisance cardiaque congestive ou accident vasculaire cérébral (AVC) ischémique est enregistrée dans les bases de données administratives. Type d'étude: Revue rétrospective de bases de données administratives couplées. Sujets et cadre de l'étude: Patients sous hémodialyse chronique en milieu hospitalier en Ontario (Canada) entre le 1er avril 2013 et le 31 mars 2017. Mesures: Les dossiers provenant des bases de données couplées de l'ICES en Ontario (Canada). Nous avons répertorié les hospitalisations dont le diagnostic principal enregistré était un infarctus du myocarde, une insuffisance cardiaque congestive ou un AVC ischémique. Nous avons ensuite évalué la fréquence des examens, des procédures, des consultations, des ordonnances de médicaments en consultation externe après la sortie de l'hôpital et des résultats dans les 30 jours suivant l'hospitalisation. Méthodologie: Nous avons utilisé des statistiques descriptives pour résumer les résultats. Des décomptes et pourcentages ont été utilisés pour les variables catégoriques; des moyennes avec écarts-types ou des médianes avec des intervalles de quartiles ont été utilisées pour les variables continues. Résultats: En tout, il y avait 14 368 patients sous hémodialyse chronique entre le 1er avril 2013 et le 31 mars 2017. Le nombre d'événements par 1 000 années-personnes était de 33,5 pour les hospitalisations avec infarctus du myocarde, de 34,2 avec insuffisance cardiaque congestive et de 12,9 pour AVC ischémique. La durée médiane (25e, 75e percentile) de l'hospitalisation était de 5 (3 à 10) jours pour l'infarctus du myocarde, de 4 (2 à 8) jours pour l'insuffisance cardiaque congestive et de 9 (4 à 18) jours pour l'AVC ischémique. Le risque de décès dans les 30 jours était de 21 % pour l'infarctus du myocarde, de 11 % pour l'insuffisance cardiaque congestive et de 19 % pour l'AVC ischémique. Limites: Les événements, les procédures et les examens enregistrés dans les bases de données administratives peuvent être sujets à des erreurs de classification par rapport aux dossiers médicaux. Conclusion: Chez les patients sous hémodialyse chronique, les hospitalisations enregistrées dans les bases de données administratives à la suite d'événements cardiovasculaires majeurs sont associées à une utilisation importante des ressources en santé et à une évolution défavorable de l'état de santé.

Association of Primary Versus Rotating Nephrologist Model of Care in Hemodialysis Programs with Patient Outcomes.

SIGNIFICANCE STATEMENT: Nephrologist staffing models for patients receiving hemodialysis vary widely. Patients may be cared for continuously by a single primary nephrologist or by a group of nephrologists on a rotating basis. It remains unclear whether these differing care models influence clinical outcomes. In this population-based cohort study of more than 14,000 incident patients on maintenance hemodialysis from Ontario, Canada, we found no difference in mortality, kidney transplantation, home dialysis initiation, hospitalizations, or emergency department visits when care was provided by a single primary nephrologist or a rotating group of nephrologists. These results suggest that primary nephrologist models do not necessarily improve objective clinical outcomes, providing reassurance to patients, providers, and administrators that both models are acceptable options.

Effectiveness of Three Doses of mRNA COVID-19 Vaccines in the Hemodialysis Population during the Omicron Period.

BACKGROUND: Coronavirus disease 2019 (COVID-19) vaccine effectiveness studies in the hemodialysis population have demonstrated that two doses of mRNA COVID-19 vaccines are effective against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe complications when Alpha and Delta were predominant variants of concern. Vaccine effectiveness after a third dose versus two doses for preventing SARS-CoV-2 infection and severe COVID-19 in the hemodialysis population against Omicron is not known. METHODS: We conducted a retrospective cohort study in Ontario, Canada, between December 1, 2021, and February 28, 2022, in the maintenance hemodialysis population who had received two versus three doses of mRNA COVID-19 vaccines. COVID-19 vaccination, SARS-CoV-2 infection, and related hospitalization and death were determined from provincial databases. The primary outcome was the first RT-PCR confirmed SARS-CoV-2 infection, and the secondary outcome was a SARS-CoV-2-related severe outcome, defined as either hospitalization or death. RESULTS: A total of 8457 individuals receiving in-center hemodialysis were included. At study initiation, 2334 (28%) individuals received three doses, which increased to 7468 (88%) individuals by the end of the study period. The adjusted hazard ratios (aHR) for SARS-CoV-2 infection (aHR, 0.58; 95% confidence interval [CI], 0.50 to 0.67) and severe outcomes (hospitalization or death) (aHR, 0.40; 95% CI, 0.28 to 0.56) were lower after three versus two doses of mRNA vaccine. Prior infection, independent of vaccine status, was associated with a lower risk of reinfection, with an aHR of 0.44 (95% CI, 0.27 to 0.73). CONCLUSIONS: Three-dose mRNA COVID-19 vaccination was associated with lower incidence of SARS-CoV-2 infection and severe SARS-CoV-2-related outcomes during the Omicron period compared with two doses.

Pre-Pregnancy eGFR and the Risk of Adverse Maternal and Fetal Outcomes: A Population-Based Study.

SIGNIFICANCE STATEMENT: Pregnancies in women with CKD carry greater risk than pregnancies in the general population. The small number of women in prior studies has limited estimates of this risk, especially among those with advanced CKD. We report the results of a population-based cohort study in Ontario, Canada, that assessed more than 500,000 pregnancies, including 600 with a baseline eGFR < 60 ml/min per 1.73 m 2 . The investigation demonstrates increases in risk of different adverse maternal and fetal outcomes with lower eGFR and further risk elevation with baseline proteinuria. BACKGROUND: CKD is a risk factor for pregnancy complications, but estimates for adverse outcomes come largely from single-center studies with few women with moderate or advanced stage CKD. METHODS: To investigate the association between maternal baseline eGFR and risk of adverse pregnancy outcomes, we conducted a retrospective, population-based cohort study of women (not on dialysis or having had a kidney transplant) in Ontario, Canada, who delivered between 2007 and 2019. The study included 565,907 pregnancies among 462,053 women. Administrative health databases captured hospital births, outpatient laboratory testing, and pregnancy complications. We analyzed pregnancies with serum creatinine measured within 2 years of conception up to 30 days after conception and assessed the impact of urine protein where available. RESULTS: The risk of major maternal morbidity, preterm delivery, and low birthweight increased monotonically across declining eGFR categories, with risk increase most notable as eGFR dropped below 60 ml/min per 1.73 m 2 . A total of 56 (40%) of the 133 pregnancies with an eGFR <45 ml/min per 1.73 m 2 resulted in delivery under 37 weeks, compared with 10% of pregnancies when eGFR exceeded 90 ml/min per 1.73 m 2 . Greater proteinuria significantly increased risk within each eGFR category. Maternal and neonatal deaths were rare regardless of baseline eGFR (<0.3% of all pregnancies). Only 7% of women with an eGFR <45 ml/min per 1.73 m 2 received dialysis during or immediately after pregnancy. CONCLUSIONS: We observed higher rates of adverse pregnancy outcomes in women with low eGFR with concurrent proteinuria. These results can help inform health care policy, preconception counseling, and pregnancy follow-up in women with CKD.

Magnesium and Fracture Risk in the General Population and Patients Receiving Dialysis: A Narrative Review.

Purpose of Review: Magnesium is an essential mineral for bone metabolism, but little is known about how magnesium intake alters fracture risk. We conducted a narrative review to better understand how magnesium intake, through supplementation, diet, or altering the concentration of dialysate magnesium, affects mineral bone disease and the risk of fracture in individuals across the spectrum of kidney disease. Sources of Information: Peer-reviewed clinical trials and observational studies. Methods: We searched for relevant articles in MEDLINE and EMBASE databases. The methodologic quality of clinical trials was assessed using a modified version of the Downs and Black criteria checklist. Key Findings: The role of magnesium intake in fracture prevention is unclear in both the general population and in patients receiving maintenance dialysis. In those with normal kidney function, 2 meta-analyses showed higher bone mineral density in those with higher dietary magnesium, whereas 1 systematic review showed no effect on fracture risk. In patients receiving maintenance hemodialysis or peritoneal dialysis, a higher concentration of dialysate magnesium is associated with a lower concentration of parathyroid hormone, but little is known about other bone-related outcomes. In 2 observational studies of patients receiving hemodialysis, a higher concentration of serum magnesium was associated with a lower risk of hip fracture. Limitations: This narrative review included only articles written in English. Observed effects of magnesium intake in the general population may not be applicable to those with chronic kidney disease particularly in those receiving dialysis.

Justification: Le magnésium est un minéral essentiel pour le métabolisme osseux, mais on en sait peu sur la façon dont un apport en magnésium modifie le risque de fracture. Nous avons procédé à un examen narratif afin de mieux comprendre comment les maladies liées à la densité minérale osseuse et le risque de fracture sont affectés par un apport en magnésium (supplémentation, régime alimentaire ou modification de la concentration de dialysat de magnésium) chez les personnes atteintes d'insuffisance rénale. Sources: Essais cliniques et études observationnelles examinés par des pairs. Méthodologie: Nous avons répertorié les articles pertinents dans les bases de données MEDLINE et EMBASE. Une version modifiée des critères de contrôle de la qualité des études de Downs et Black a servi à évaluer la qualité méthodologique des essais cliniques retenus. Principaux résultats: Le rôle d'un apport en magnésium dans la prévention des fractures n'est pas clair, tant dans la population générale que chez les patients sous dialyse d'entretien. Chez les personnes ayant une fonction rénale normale, deux méta-analyses ont montré que les personnes dont le régime alimentaire est riche en magnésium présentent une densité minérale osseuse plus élevée; alors qu'une revue systématique n'a montré aucun effet sur le risque de fracture. Chez les patients sous hémodialyse d'entretien ou dialyse péritonéale, une concentration plus élevée de dialysat de magnésium est associée à une plus faible concentration d'hormone parathyroïdienne, mais on en sait peu sur les autres effets liés aux os. Dans deux études observationnelles portant sur des patients sous hémodialyse, une concentration plus élevée de magnésium sérique a été associée à un risque plus faible de fracture de la hanche. Limites: Cet examen narratif ne comprend que des articles rédigés en anglais. Il est possible que les effets d'un apport en magnésium observés dans la population générale ne puissent s'appliquer aux personnes atteintes d'une néphropathie chronique, en particulier aux personnes sous dialyse.

Association of an Acute Kidney Injury Follow-up Clinic With Patient Outcomes and Care Processes: A Cohort Study.

RATIONALE & OBJECTIVE: To determine whether attendance at an acute kidney injury (AKI) follow-up clinic is associated with reduced major adverse kidney events. STUDY DESIGN: Propensity-matched cohort study. SETTING & PARTICIPANTS: Patients hospitalized with AKI in Ontario, Canada, from February 1, 2013, through September 30, 2017, at a single clinical center, who were not receiving dialysis when discharged. EXPOSURE: Standardized assessment by a nephrologist. OUTCOMES: Time to a major adverse kidney event, defined as death, initiation of maintenance dialysis, or incident/progressive chronic kidney disease. ANALYTICAL APPROACH: Propensity scores were used to match each patient who attended an AKI follow-up clinic to 4 patients who received standard care. Cox proportional hazards models were fit to assess the association between the care within an AKI follow-up clinic and outcomes. To avoid immortal time bias, we randomly assigned index dates to the comparator group. RESULTS: We matched 164 patients from the AKI follow-up clinic to 656 patients who received standard care. During a mean follow-up of 2.2±1.3 (SD) years, care in the AKI follow-up clinic was not associated with a reduction in major adverse kidney events relative to standard care (22.1 vs 24.7 events per 100 patient-years; HR, 0.91 [95% CI, 0.75-1.11]). The AKI follow-up clinic was associated with a lower risk of all-cause mortality (HR, 0.71 [95% CI, 0.55-0.91]). Patients aged at least 66 years who attended the AKI follow-up clinic were more likely to receive ß-blockers (HR, 1.34 [95% CI, 1.02-1.77]) and statins (HR, 1.35 [95% CI, 1.05-1.74]), but not angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (HR, 1.21 [95% CI, 0.94-1.56]). LIMITATIONS: Single-center study and residual confounding. CONCLUSIONS: Specialized postdischarge follow-up for AKI survivors was not associated with a lower risk of major adverse kidney events but was associated with a lower risk of death and increased prescriptions for some cardioprotective medications.

Incidence of cardiovascular disease and mortality in childhood solid organ transplant recipients: a population-based study.

BACKGROUND: With improved survival among children after transplantation, our understanding of the risk for developing other comorbidities is improving, yet little is known about the long-term risk of cardiovascular events and mortality after solid organ transplantation. METHODS: In a cohort study using health administrative data, we compared cardiovascular events in children (n = 615) with liver, lung, kidney, small bowel, or multi-organ transplant at the Hospital for Sick Children, Toronto, Canada, with asthmatic children (n = 481,697) between 1996 and 2014. Outcomes included non-fatal cardiovascular events, cardiovascular death, all-cause mortality, and a composite of non-fatal and fatal cardiovascular events. Time-stratified Cox proportional hazards models were used. RESULTS: Among 615 children, 317 (52%) were recipients of kidneys, 253 (41%) of livers, and the remaining 45 (7%) had lung, small bowel, or multi-organ transplants. Median follow-up was 12.1 [7.2, 16.7] years. Non-fatal incident cardiovascular events were 34 times higher among solid organ transplant recipients than non-transplanted children (incidence rate ratio (IRR) 34.4, 95% CI: 25.5, 46.4). Among transplant recipients, the cumulative incidence of non-fatal and fatal cardiovascular events was 2.3% and 13.0%, 5 and 15 years after transplantation, respectively. CONCLUSIONS: Increased rate of cardiovascular events in children after transplantation highlights the need for surveillance during transition into adulthood and beyond. A higher resolution version of the Graphical abstract is available as Supplementary information.

Enhance Access to Kidney Transplantation and Living Kidney Donation (EnAKT LKD): Statistical Analysis Plan of a Registry-Based, Cluster-Randomized Clinical Trial.

Background: Enhance Access to Kidney Transplantation and Living Kidney Donation (EnAKT LKD) is a quality improvement intervention designed to enhance access to kidney transplantation and living kidney donation. We conducted a cluster-randomized clinical trial to evaluate the effect of the intervention versus usual care on completing key steps toward receiving a kidney transplant. Objective: To prespecify the statistical analysis plan for the EnAKT LKD trial. Design: The EnAKT LKD trial is a pragmatic, 2-arm, parallel-group, registry-based, open-label, cluster-randomized, superiority, clinical trial. Randomization was performed at the level of the chronic kidney disease (CKD) programs (the "clusters"). Setting: Twenty-six CKD programs in Ontario, Canada. Participants: More than 10 000 patients with advanced CKD (ie, patients approaching the need for dialysis or receiving maintenance dialysis) with no recorded contraindication to receiving a kidney transplant. Methods: The trial data (including patient characteristics and outcomes) will be obtained from linked administrative health care databases (the "registry"). Stratified covariate-constrained randomization was used to allocate the 26 CKD programs (1:1) to provide the intervention or usual care from November 1, 2017, to December 31, 2021 (4.17 years). CKD programs in the intervention arm received the following: (1) support for local quality improvement teams and administrative needs; (2) tailored education and resources for staff, patients, and living kidney donor candidates; (3) support from kidney transplant recipients and living kidney donors; and (4) program-level performance reports and oversight by program leaders. Outcomes: The primary outcome is completing key steps toward receiving a kidney transplant, where up to 4 unique steps per patient will be considered: (1) patient referred to a transplant center for evaluation, (2) a potential living kidney donor begins their evaluation at a transplant center to donate a kidney to the patient, (3) patient added to the deceased donor transplant waitlist, and (4) patient receives a kidney transplant from a living or deceased donor. Analysis plan: Using an intent-to-treat approach, the primary outcome will be analyzed using a patient-level constrained multistate model adjusting for the clustering in CKD programs. Trial Status: The EnAKT LKD trial period is November 1, 2017, to December 31, 2021. We expect to analyze and report the results once the data for the trial period is available in linked administrative health care databases. Trial Registration: The EnAKT LKD trial is registered with the U.S. National Institute of Health at clincaltrials.gov (NCT03329521 available at https://clinicaltrials.gov/ct2/show/NCT03329521). Statistical Analytic Plan: Version 1.0 August 26, 2022.

Contexte: EnAKT LKD est une intervention d'amélioration de la qualité visant à améliorer l'accès à la transplantation rénale et au don vivant de rein. Nous avons mené un essai clinique randomisé par grappes afin d'évaluer l'effet de l'intervention, par rapport aux soins habituels, sur le taux d'étapes clés réalisées dans le processus de réception d'une greffe de rein. Objectif: Exposer les grandes lignes du plan d'analyse statistique de l'essai EAKT LKD. Conception: EAKT LKD est un essai clinique pragmatique ouvert, à deux bras, en groupes parallèles, basé sur un registre, et randomisé en grappes. La randomisation a été réalisée au niveau des programmes d'insuffisance rénale chronique (IRC) (les « grappes ¼). Cadre: 26 programmes d'IRC en Ontario (Canada). Sujets: Plus de 10 000 patients atteints d'IRC de stade avancé (des patients approchant le besoin de dialyse ou recevant une hémodialyse d'entretien) sans contre-indication documentée à la greffe rénale. Méthodologie: Les données de l'essai (y compris les caractéristiques et les résultats des patients) seront obtenues à partir de bases de données administratives en santé (le « registre ¼). La randomisation stratifiée avec contraintes de covariables a servi à répartir les 26 programmes d'IRC (1:1) selon qu'ils allaient fournir l'intervention ou les soins habituels entre le 1er novembre 2017 et le 31 décembre 2021 (4,17 ans). Les programmes d'IRC du bras d'intervention ont eu droit au soutien suivant: (1) des équipes locales d'amélioration de la qualité et du soutien administratif; (2) de l'information et des ressources sur mesure pour le personnel, les patients et les donneurs vivants; (3) du soutien de la part de receveurs et de donneurs vivants; et (4) des rapports sur le rendement au niveau du programme et une surveillance assurée par les chefs de programme. Résultats: Le principal critère d'évaluation est le taux d'étapes clés accomplies vers la réception d'une greffe de rein, où jusqu'à quatre étapes uniques par patient seront comptabilisées: (1) le patient est aiguillé vers un centre de transplantation pour évaluation; (2) un possible donneur vivant de rein contacte un centre de transplantation pour un receveur en particulier et amorce son évaluation; (3) le patient est ajouté à la liste d'attente pour une transplantation d'un donneur décédé, et (4) le patient reçoit une greffe de rein d'un donneur vivant ou décédé. Plan d'analyse: Selon une approche fondée sur l'intention de traiter, le critère d'évaluation principal sera analysé au niveau du patient en utilisant un modèle multiétats contraint, corrigé dans les programmes d'IRC en fonction du regroupement. Statut de l'essai: L'essai EnAKT LKD s'est tenu du 1er novembre 2017 au 31 décembre 2021. Nous analyserons les résultats et en rendrons compte dès que les données seront disponibles dans les bases de données administratives couplées du système de santé.

Machine learning algorithms to identify cluster randomized trials from MEDLINE and EMBASE.

BACKGROUND: Cluster randomized trials (CRTs) are becoming an increasingly important design. However, authors of CRTs do not always adhere to requirements to explicitly identify the design as cluster randomized in titles and abstracts, making retrieval from bibliographic databases difficult. Machine learning algorithms may improve their identification and retrieval. Therefore, we aimed to develop machine learning algorithms that accurately determine whether a bibliographic citation is a CRT report. METHODS: We trained, internally validated, and externally validated two convolutional neural networks and one support vector machine (SVM) algorithm to predict whether a citation is a CRT report or not. We exclusively used the information in an article citation, including the title, abstract, keywords, and subject headings. The algorithms' output was a probability from 0 to 1. We assessed algorithm performance using the area under the receiver operating characteristic (AUC) curves. Each algorithm's performance was evaluated individually and together as an ensemble. We randomly selected 5000 from 87,633 citations to train and internally validate our algorithms. Of the 5000 selected citations, 589 (12%) were confirmed CRT reports. We then externally validated our algorithms on an independent set of 1916 randomized trial citations, with 665 (35%) confirmed CRT reports. RESULTS: In internal validation, the ensemble algorithm discriminated best for identifying CRT reports with an AUC of 98.6% (95% confidence interval: 97.8%, 99.4%), sensitivity of 97.7% (94.3%, 100%), and specificity of 85.0% (81.8%, 88.1%). In external validation, the ensemble algorithm had an AUC of 97.8% (97.0%, 98.5%), sensitivity of 97.6% (96.4%, 98.6%), and specificity of 78.2% (75.9%, 80.4%)). All three individual algorithms performed well, but less so than the ensemble. CONCLUSIONS: We successfully developed high-performance algorithms that identified whether a citation was a CRT report with high sensitivity and moderately high specificity. We provide open-source software to facilitate the use of our algorithms in practice.

Using Administrative Health Care Databases to Identify Patients With End-Stage Kidney Disease With No Recorded Contraindication to Receiving a Kidney Transplant.

Background: Administrative health care databases can be efficiently analyzed to describe the degree to which patients with end-stage kidney disease (ESKD) have access to kidney transplantation. Measures of access to transplantation are better represented when restricting to only those patients eligible to receive a kidney transplant. The way administrative data can be used to assess kidney transplant eligibility in the absence of clinical data has not been well described. Objective: To demonstrate a method that uses administrative health care databases to identify patients with ESKD who have no recorded contraindication to receiving a kidney transplant. Design and setting: Population-based cohort study using linked administrative health care databases in Ontario, Canada. Patients: Adult patients with ESKD approaching the need for dialysis (predialysis) or receiving maintenance dialysis between January 1, 2013 and March 31, 2015 in Ontario, Canada. Measurements: Recipient of a kidney-only or kidney-pancreas transplant. Methods: We assessed more than 80 baseline characteristics, including demographic information, comorbidities, kidney-specific characteristics, and referral and listing criteria for kidney transplantation. We compared these characteristics between patients who did and did not receive a kidney transplant. Results: We included 23 642 patients with ESKD (11 195 who were predialysis and 12 447 receiving maintenance dialysis). Over a median follow-up of 3.2 years (25th, 75th percentile: 1.3, 5.6), 3215 (13.6%) received a kidney-only or kidney-pancreas transplant. Of the studied characteristics available in administrative databases, >97% of patients with one or more of these characteristics did not receive a kidney transplant during follow-up: ESKD-modified Charlson Comorbidity Index score ≥7 (a higher score represents greater comorbidity), home oxygen use, age above 75 years, dementia, living in a long-term care facility, receiving at least one physician house call in the past year, and a combination of select malignancies (ie, lung, lymphoma, cervical, colorectal, liver, active multiple myeloma, and bladder cancer). Using these combined criteria reduced the total number of patients from 23 642 to 12 539 with no recorded contraindications to transplant (a 47% reduction), while the proportion who received a kidney transplant changed from 13.6% (denominator of 23 642) to 24.9% (denominator of 12 539). Limitations: Administrative databases are unable to capture all the complexities of determining transplant eligibility. Conclusion: We identified several criteria available within administrative health care databases that can be used to identify patients with ESKD who have no recorded contraindications to kidney transplant. These criteria could be applied when reporting measures of access to kidney transplantation that require knowledge of transplant eligibility.

Contexte: Les bases de données administratives en santé peuvent être analysées efficacement pour décrire le degré d'accès des patients atteints d'insuffisance rénale terminale (IRT) à une transplantation. Les mesures de l'accès à la transplantation sont mieux représentées lorsqu'on se limite aux patients admissibles pour recevoir une greffe rénale. On manque toutefois d'information sur la façon dont les données administratives peuvent être utilisées, en l'absence de données cliniques, pour évaluer l'admissibilité à une greffe rénale. Objectif: Démontrer une méthode utilisant les bases de données administratives en santé pour identifier les patients atteints d'IRT sans contre-indication à une greffe rénale. Type d'étude: Étude de cohorte représentative d'une population réalisée en Ontario (Canada) à partir des données administratives en santé. Sujets: Des patients ontariens (Canada) atteints d'IRT qui approchaient le besoin de dialyse (prédialyse) ou qui recevaient des traitements de dialyse d'entretien entre le 1er janvier 2013 et le 31 mars 2015. Mesures: Les receveurs d'une greffe de rein seulement ou de rein-pancréas. Méthodologie: Nous avons évalué plus de 80 caractéristiques initiales, notamment les données démographiques et les comorbidités des patients, et les caractéristiques particulières du rein; en plus des critères d'aiguillage et d'inscription pour une greffe rénale. Ces caractéristiques ont été comparées entre les patients greffés et ceux qui n'avaient pas reçu une greffe. Résultats: Nous avons inclus 23 642 patients atteints d'IRT (11 195 en prédialyse et 12 447 sous dialyse d'entretien). Pendant un suivi médian de 3,2 ans (25e percentile: 1,3 an; 75e percentile: 5,6 ans), 3 215 patients (13,6 %) ont reçu une greffe (rein seulement ou rein-pancréas). Plus de 97 % des patients présentant une ou plusieurs des caractéristiques suivantes, disponibles dans les bases de données, n'avaient pas reçu de greffe rénale pendant le suivi: avoir un score d'au moins 7 à l'indice de Charlson ajusté pour l'IRT (un score élevé représente une plus grande comorbidité), consommer de l'oxygène à domicile, avoir plus de 75 ans, souffrir de démence, vivre dans un établissement de soins de longue durée, avoir reçu au moins un appel du médecin au cours de la dernière année et présenter une combinaison de certaines tumeurs malignes (poumons, lymphome, col de l'utérus, colon, rectum, foie, vessie et myélome multiple actif). L'utilisation de ces critères combinés a réduit le nombre total de patients sans contre-indications à la transplantation de 23 642 à 12 539 (réduction de 47 %), faisant ainsi passer la proportion de patients ayant reçu une transplantation rénale de 13,6 % (dénominateur de 23 642) à 24,9 % (dénominateur de 12 539). Limites: Les bases de données administratives ne sont pas en mesure de saisir toutes les complexités liées à la détermination de l'admissibilité à une transplantation. Conclusion: Nous avons répertorié plusieurs critères disponibles dans les bases de données administratives en santé qui permettent d'identifier les patients atteints d'IRT sans contre-indications à la transplantation rénale. Ces critères pourraient être appliqués lors de la communication de mesures de l'accès à la transplantation rénale qui exigent de connaître l'admissibilité du patient à une transplantation.

Initiation Dose of Allopurinol and the Risk of Severe Cutaneous Reactions in Older Adults With CKD: A Population-Based Cohort Study.

RATIONALE & OBJECTIVE: Allopurinol should be started at lower doses in patients with chronic kidney disease (CKD) to avoid adverse effects. We examined the risk of severe cutaneous reactions in older adults with CKD who were newly prescribed allopurinol at varied doses. STUDY DESIGN: Population-based cohort study using linked health care databases. SETTING & PARTICIPANTS: Patients in Ontario, Canada (2008-2019) aged ≥66 years, with an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2, and who were new users of allopurinol. EXPOSURE: A new prescription for allopurinol >100 mg/d versus a dose ≤100 mg/d. OUTCOME: The primary outcome was a hospital visit with a severe cutaneous reaction within 180 days of starting allopurinol. Secondary outcomes included all-cause hospitalization and all-cause mortality. ANALYTICAL APPROACH: The exposure and referent groups were balanced on indicators of baseline health using inverse probability of treatment weighting on the propensity score. Weighted risk ratios (RR) were obtained using modified Poisson regression and weighted risk differences (RD) using binomial regression. RESULTS: Of 47,315 patients (median age, 76 years; median eGFR, 45 mL/min/1.73 m2), 55% started allopurinol at >100 mg/d. Starting allopurinol at >100 versus ≤100 mg/d was associated with an increased risk of a severe cutaneous reaction: number of events (weighted), 103 of 25,802 (0.40%) versus 46 of 25,816 (0.18%), respectively (weighted RR, 2.25 [95% CI, 1.50-3.37]; weighted RD, 0.22% [95% CI, 0.12%-0.32%]. Starting allopurinol at >100 versus ≤100 mg/d was associated with an increased risk of all-cause hospitalization but not with all-cause mortality. LIMITATIONS: This study was underpowered to detect risk differences in the association of allopurinol dose with outcomes across eGFR categories (ie, 45-59, 30-44, and <30 mL/min/1.73 m2). CONCLUSIONS: Older patients with CKD who started allopurinol at >100 mg/d versus ≤100 mg/d were twice as likely to visit a hospital with a severe cutaneous reaction in the next 180 days.

Fracture Risk of Sodium-Glucose Cotransporter-2 Inhibitors in Chronic Kidney Disease.

BACKGROUND AND OBJECTIVES: Sodium-glucose cotransporter-2 (SGLT2) inhibitors have been associated with a higher risk of skeletal fractures in some randomized, placebo-controlled trials. Secondary hyperparathyroidism and increased bone turnover (also common in CKD) may contribute to the observed fracture risk. We aimed to determine if SGLT2 inhibitor use associates with a higher risk of fractures compared with dipeptidyl peptidase-4 (DPP-4) inhibitors, which have no known association with fracture risk. We hypothesized that this risk, if present, would be greatest in patients with lower eGFR. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a population-based cohort study in Ontario, Canada between 2015 and 2019 using linked provincial administrative data to compare the incidence of fracture between new users of SGLT2 inhibitors and DPP-4 inhibitors. We used inverse probability of treatment weighting on the basis of propensity scores to balance the two groups of older adults (≥66 years of age) on indicators of baseline health. We compared the 180- and 365-day cumulative incidence rates of fracture between groups. Prespecified subgroup analyses were conducted by eGFR category (≥90, 60 to <90, 45 to <60, and 30 to <45 ml/min per 1.73 m2). Weighted hazard ratios were obtained using Cox proportional hazard regression. RESULTS: After weighting, we identified a total of 38,994 new users of a SGLT2 inhibitor and 37,449 new users of a DPP-4 inhibitor and observed a total of 342 fractures at 180 days and 689 fractures at 365 days. The weighted 180- and 365-day risks of a fragility fracture did not significantly differ between new users of a SGLT2 inhibitor versus a DPP-4 inhibitor: weighted hazard ratio, 0.95 (95% confidence interval, 0.79 to 1.13) and weighted hazard ratio, 0.88 (95% confidence interval, 0.88 to 1.00), respectively. There was no observed interaction between fracture risk and eGFR category (P=0.53). CONCLUSIONS: In this cohort study of older adults, starting a SGLT2 inhibitor versus DPP-4 inhibitor was not associated with a higher risk of skeletal fracture, regardless of eGFR.