Defining pre-emptive living kidney donor transplantation as a quality indicator.

Quality indicators in kidney transplants are needed to identify care gaps and improve access to transplants. We used linked administrative health care databases to examine multiple ways of defining pre-emptive living donor kidney transplants, including different patient cohorts and censoring definitions. We included adults from Ontario, Canada with advanced chronic kidney disease between January 1, 2013, to December 31, 2018. We created 4 unique incident patient cohorts, varying the eligibility by the risk of progression to kidney failure and whether individuals had a recorded contraindication to kidney transplant (eg, home oxygen use). We explored the effect of 4 censoring event definitions. Across the 4 cohorts, size varied substantially from 20 663 to 9598 patients, with the largest reduction (a 43% reduction) occurring when we excluded patients with ≥1 recorded contraindication to kidney transplantation. The incidence rate (per 100 person-years) of pre-emptive living donor kidney transplant varied across cohorts from 1.02 (95% CI: 0.91-1.14) for our most inclusive cohort to 2.21 (95% CI: 1.96-2.49) for the most restrictive cohort. Our methods can serve as a framework for developing other quality indicators in kidney transplantation and monitoring and improving access to pre-emptive living donor kidney transplants in health care systems.

Vaccine Effectiveness Against SARS-CoV-2 Infection and Severe Outcomes in the Maintenance Dialysis Population in Ontario, Canada.

BACKGROUND: Vaccination studies in the hemodialysis population have demonstrated decreased antibody response compared with healthy controls, but vaccine effectiveness for preventing SARS-CoV-2 infection and severe disease is undetermined. METHODS: We conducted a retrospective cohort study in the province of Ontario, Canada, between December 21, 2020, and June 30, 2021. Receipt of vaccine, SARS-CoV-2 infection, and related severe outcomes (hospitalization or death) were determined from provincial health administrative data. Receipt of one and two doses of vaccine were modeled in a time-varying cause-specific Cox proportional hazards model, adjusting for baseline characteristics, background community infection rates, and censoring for non-COVID death, recovered kidney function, transfer out of province, solid organ transplant, and withdrawal from dialysis. RESULTS: Among 13,759 individuals receiving maintenance dialysis, 2403 (17%) were unvaccinated and 11,356 (83%) had received at least one dose by June 30, 2021. Vaccine types were BNT162b2 (n=8455, 74%) and mRNA-1273 (n=2901, 26%); median time between the first and second dose was 36 days (IQR 28-51). The adjusted hazard ratio (HR) for SARS-CoV-2 infection and severe outcomes for one dose compared with unvaccinated was 0.59 (95% CI, 0.46 to 0.76) and 0.54 (95% CI, 0.37 to 0.77), respectively, and for two doses compared with unvaccinated was 0.31 (95% CI, 0.22 to 0.42) and 0.17 (95% CI, 0.1 to 0.3), respectively. There were no significant differences in vaccine effectiveness among age groups, dialysis modality, or vaccine type. CONCLUSIONS: COVID-19 vaccination is effective in the dialysis population to prevent SARS-CoV-2 infection and severe outcomes, despite concerns about suboptimal antibody responses.

Effectiveness of first, second, and third COVID-19 vaccine doses in solid organ transplant recipients: A population-based cohort study from Canada.

Limited data exists on the effectiveness of a third COVID-19 vaccine dose in solid organ transplant recipients. We conducted a population-based cohort study using linked healthcare databases from Ontario, Canada to answer this question. We included solid organ transplant recipients (n = 12,842) as of December 14, 2020, with follow-up until November 28, 2021. We used an extended Cox proportional hazards model with vaccination status, including BNT162b2, mRNA-1273, and ChAdOx1 vaccines, modeled as a time-dependent exposure. Individuals started in the unvaccinated category (reference) and could contribute person-time to first, second, and third doses. Over a median follow-up of 349 days, 12.7% (n = 1632) remained unvaccinated, 54.1% (n = 6953) received 3 doses, and 488 (3.8%) tested positive for SARS-CoV-2 (of which 260 [53.3%] had a clinically important outcome [i.e., hospitalization or death]). Adjusted vaccine effectiveness against infection was 31% (95% CI: 2, 51%), 46% (95% CI: 21, 63%), and 72% (95% CI: 43, 86%) for one, two, and three doses. Vaccine effectiveness against clinically important outcomes was 38% (95% CI: 4, 61%), 54% (95% CI: 23, 73%), and 67% (95% CI: 11, 87%). Vaccine effectiveness in solid organ transplant recipients is lower than the general population, however, vaccine effectiveness improved following a third dose.

Promoting deceased organ and tissue donation registration in family physician waiting rooms (RegisterNow-1): a pragmatic stepped-wedge, cluster randomized controlled registry trial.

BACKGROUND: The shortage of available organs for life-saving transplants persists worldwide. While a majority support donating their organs or tissue when they die, many have not registered their wish to do so. When registered, next of kin are much more likely to follow-through with the decision to donate. In many countries, most people visit their family physician office each year and this setting is a promising, yet underused, site where more people could register for deceased organ donation. Our primary aim was to evaluate the effectiveness of an intervention to promote organ donation registration in family physician's offices. METHODS: We developed an intervention to address barriers and enablers to organ donation registration that involved physician office reception staff inviting patients to register on a tablet in the waiting room while they waited for their appointment. We conducted a cross-sectional stepped-wedge cluster randomized controlled registry trial to evaluate the intervention. We recruited six family physician offices in Canada. All offices began with usual care and then every two weeks, one office (randomly assigned) started the intervention until all offices delivered the intervention. The primary outcome was registration for deceased organ donation in the provincial organ registration registry, assessed within the 7 days of the physician visit. At the end of the trial, we also conducted interviews with clinic staff to assess any barriers and enablers to delivering the intervention. RESULTS: The trial involved 24,616 patient visits by 13,562 unique patients: 12,484 visits in the intervention period and 12,132 in the control period. There was no statistically significant difference in the percentage of patients registered for deceased organ donation in the intervention versus control period (48.0% vs 46.2%; absolute difference after accounting for the secular trend: 0.12%; 95% CI: - 2.30, 2.54; p=0.92). Interviews with clinic staff indicated location of the tablet within a waiting room, patient rapport, existing registration, confidence and motivation to deliver the intervention and competing priorities as barriers and enablers to delivery. CONCLUSIONS: Our intervention did not increase donor registration. Nonetheless, family physician offices may still remain a promising setting to develop and evaluate better interventions to increase organ donation registration. TRIAL REGISTRATION: NCT03213171.

Opioid prescribing practices in chronic kidney disease: a population-based cohort study.

BACKGROUND: Chronic pain is common, and its management is complex in patients with chronic kidney disease (CKD), but limited data are available on opioid prescribing. We examined opioid prescribing for non-cancer and non-end-of-life care in patients with CKD. METHODS: This was a population-based retrospective cohort study using administrative databases in Ontario, Canada which included adults with CKD defined by an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 from 1 November 2012 to 31 December 2018 and estimated the proportion of opioid prescriptions (type, duration, dose, potentially inappropriate prescribing, etc.) within 1 year of cohort entry. Prescriptions had to precede dialysis, kidney transplant or death. RESULTS: We included 680 445 adults with CKD, and 198 063 (29.1%) were prescribed opioids. Codeine (14.9%) and hydromorphone (7.2%) were the most common opioids. Among opioid users, 24.3% had repeated or long-term use, 26.1% were prescribed high doses and 56.8% were new users. Opioid users were more likely to be female, had cardiac disease or a mental health diagnosis, and had more healthcare visits. The proportions for potentially inappropriate prescribing indicators varied (e.g. 50.1% with eGFR <30 were prescribed codeine, and 20.6% of opioid users were concurrently prescribed benzodiazepines, while 7.2% with eGFR <30 mL/min/1.73 m2 were prescribed morphine, and 7.0% were received more than one opioid concurrently). Opioid prescriptions declined with time (2013 cohort: 31.1% versus 2018 cohort: 24.5%; p <0.0001), as did indicators of potentially inappropriate prescribing. CONCLUSIONS: Opioid use was common in patients with CKD. While opioid prescriptions and potentially inappropriate prescribing have declined in recent years, interventions to improve pain management without the use of opioids and education on safer prescribing practices are needed.

Pre-transplant maintenance dialysis duration and outcomes after kidney transplantation: A multicenter population-based cohort study.

The association between pre-transplant dialysis duration and post-transplant outcomes may vary by the population and endpoints studied. We conducted a population-based cohort study using linked healthcare databases from Ontario, Canada including kidney transplant recipients (n = 4461) from 2004 to 2014. Our primary outcome was total graft failure (i.e., death, return to dialysis, or pre-emptive re-transplant). Secondary outcomes included death-censored graft failure, death with graft function, mortality, hospitalization for cardiovascular events, hospitalization for infection, and hospital readmission. We presented results by pre-transplant dialysis duration (pre-emptive transplant, and .01-1.43, 1.44-2.64, 2.65-4.25, 4.26-6.45, and 6.46-36.5 years, for quintiles 1-5). After adjusting for clinical characteristics, pre-emptive transplantation was associated with a lower rate of total graft failure (adjusted hazard ratio [aHR] .68, 95% CI: .46, .99), while quintile 4 was associated with a higher rate (aHR 1.31, 95% CI: 1.01, 1.71), when compared to quintile 1. There was no significant relationship between dialysis duration and death-censored graft failure, cardiovascular events, or hospital readmission. For death with graft function and mortality, quintiles 3-5 had a significantly higher aHR compared to quintile 1, while for infection, quintiles 2-5 had a higher aHR. Longer time on dialysis was associated with an increased rate of several adverse post-transplant outcomes.

Partnering with Patients to Enhance Access to Kidney Transplantation and Living Kidney Donation.

Kidney transplantation gives many patients with kidney failure a longer and healthier life. Unfortunately, some transplant-eligible patients will never receive one. In this paper, we describe how patients and researchers collaborated on new strategies and programs to enhance access to kidney transplantation and living kidney donation. These efforts led to the creation of the Transplant Ambassador Program (TAP). TAP is a patient-led program that helps connect patients who have kidney failure to individuals who have successfully received a kidney transplant or donated a kidney. We also detail barriers, facilitators and lessons learned from engaging patients in research.

Interventions for increasing solid organ donor registration.

BACKGROUND: A solution for increasing the number of available organs for transplantation is to encourage more individuals to register a commitment for deceased organ donation. However, the percentage of the population registered for organ donation remains low in many countries. OBJECTIVES: To evaluate the benefits and harms of various interventions used to increase deceased organ donor registration. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 11 August 2020 through contact with an Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: We included all randomised controlled trials (RCTs), cluster RCTs and quasi-RCTs of interventions to promote deceased organ donor registration. We included studies if they measured self-reported or verified donor registration, intention to donate, intention to register a decision or number of individuals signing donor cards as outcomes. DATA COLLECTION AND ANALYSIS: Two authors independently assessed retrieved studies and extracted data from included studies. We assessed studies for risk of bias. We obtained summary estimates of effect using a random-effects model and expressed results as risk ratios (RR) (95% confidence intervals; CI) for dichotomous outcomes and mean difference (MD; 95% CI) or standardised mean difference (SMD; 95% CI) for continuous outcomes. In multi-arm trials, data were pooled to create single pair-wise comparisons. Analyses were stratified by specific intervention setting where available. MAIN RESULTS: Our search strategy identified 46 studies (47 primary articles, including one abstract) comprising 24 parallel RCTs, 19 cluster RCTs and 3 quasi-RCTs. Sample sizes ranged from 138 to 1,085,292 (median = 514). A total of 16 studies measured registration behaviour, 27 measured intention to register/donate and three studies measured both registration behaviour and intention to register. Interventions were delivered in a variety of different settings: schools (14 studies), driver's motor vehicle (DMV) centres (5), mail-outs (4), primary care centres (3), workplaces (1), community settings (7) and general public (12). Interventions were highly varied in terms of their content and included strategies such as educational sessions and videos, leveraging peer leaders, staff training, message framing, and priming. Most studies were rated as having high or unclear risk of bias for random sequence generation and allocation concealment and low risk for the remainder of the domains. Data from 34/46 studies (74%) were available for meta-analysis. Low certainty evidence showed organ donation registration interventions had a small overall effect on improving registration behaviour (16 studies, 1,294,065 participants: RR 1.30, 95% CI 1.19 to 1.43, I2 = 84%), intention to register/donate (dichotomous) (10 studies, 10,838 participants: RR 1.21, 95% CI 1.03 to 1.42, I2 = 91%) and intention to register/donate (continuous) (9 studies, 3572 participants: SMD 0.23, 95% CI 0.11 to 0.36, I2 = 67%). Classroom-based interventions delivered in a lecture format by individuals from the transplant community may be effective at increasing intention to register/donate (3 studies, 675 participants: RR 1.33, 95% CI 1.15 to 1.55, I² = 0%). Community interventions targeting specific ethnic groups were generally effective at increasing registration rates (k = 5, n = 4186; RR 2.14, 95% CI 1.35 to 3.40, I² = 85%), although heterogeneity was high. In particular, interventions delivered in the community by trained peer-leaders appear to be effective (3 studies, 3819 participant: RR 2.09, 95% CI 1.08 to 4.06, I² = 87%), although again, the data lacked robustness. There was some evidence that framing messages (e.g. anticipated regret) and priming individuals (e.g. reciprocity) in a certain way may increase intention to register/donate, however, few studies measured this effect on actual registration. Overall, the studies varied significantly in terms of design, setting, content and delivery. Selection bias was evident and a quarter of the studies could not be included in the meta-analysis due to incomplete outcome data reporting. No adverse events were reported. AUTHORS' CONCLUSIONS: In our review, we identified a variety of approaches used to increase organ donor registration including school-based educational sessions and videos, leveraging peer leaders in the community, DMV staff training, targeted messaging and priming. The variability in outcome measures used and incompleteness in reporting meant that most data could not be combined for analysis. When data were combined, overall effect sizes were small in favour of intervention groups over controls, however, there was significant variability in the data. There was some evidence that leveraging peer-leaders in the community to deliver organ donation education may improve registration rates and classroom-based education from credible individuals (i.e. members of the transplant community) may improve intention to register/donate, however, there is no clear evidence favouring any particular approach. There was mixed evidence for simple, low-intensity interventions utilising message framing and priming. However, it is likely that interest in these strategies will persist due to their reach and scalability. Further research is therefore required to adequately address the question of the most effective interventions for increasing deceased organ donor registration.

Incidence and outcomes of invasive fungal infection among solid organ transplant recipients: A population-based cohort study.

BACKGROUND: Invasive fungal infection (IFI) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. The long-term probability of post-transplant IFI is poorly understood. METHODS: We conducted a population-based cohort study using linked administrative healthcare databases from Ontario, Canada, to determine the incidence rate; 1-, 5-, and 10-year cumulative probabilities of IFI; and post-IFI all-cause mortality in SOT recipients from 2002 to 2016. We also determined post-IFI, death-censored renal allograft failure. RESULTS: We included 9326 SOT recipients (median follow-up: 5.35 years). Overall, the incidence of IFI was 8.3 per 1000 person-years. The 1-year cumulative probability of IFI was 7.4% for lung, 5.4% for heart, 1.8% for liver, 1.2% for kidney-pancreas, and 1.1% for kidney-only allograft recipients. Lung transplant recipients had the highest incidence rate and 10-year probability of IFI: 43.0 per 1000 person-years and 26.4%, respectively. The 1-year all-cause mortality rate after IFI was 34.3%. IFI significantly increased the risk of mortality in SOT recipients over the entire follow-up period (hazard ratio: 6.50, 95% CI: 5.69-7.42). The 1-year probability of death-censored renal allograft failure after IFI was 9.8%. CONCLUSION: Long-term cumulative probability of IFI varies widely among SOT recipients. Lung transplantation was associated with the highest incidence of IFI with considerable 1-year all-cause mortality.

Risk of radiation-associated intracranial malignancy after stereotactic radiosurgery: a retrospective, multicentre, cohort study.

BACKGROUND: A major concern of patients who have stereotactic radiosurgery is the long-term risk of having a secondary intracranial malignancy or, in the case of patients with benign tumours treated with the technique, the risk of malignant transformation. The incidence of stereotactic radiosurgery-associated intracranial malignancy remains unknown; therefore, our aim was to estimate it in a population-based study to assess the long-term safety of this technique. METHODS: We did a population-based, multicentre, cohort study at five international radiosurgery centres (Na Homolce Hospital, Prague, Czech Republic [n=2655 patients]; Ruber International Hospital, Madrid, Spain [n=1080], University of Pittsburgh Medical Center, Pittsburgh, PA, USA [n=1027]; University of Virginia, Charlottesville, VA, USA [n=80]; and NYU Langone Health System, New York, NY, USA [n=63]). Eligible patients were of any age, and had Gamma Knife radiosurgery for arteriovenous malformation, trigeminal neuralgia, or benign intracranial tumours, which included vestibular or other benign schwannomas, WHO grade 1 meningiomas, pituitary adenomas, and haemangioblastoma. Patients were excluded if they had previously had radiotherapy or did not have a minimum follow-up time of 5 years. The primary objective of the study was to estimate the incidence of stereotactic radiosurgery-associated intracranial malignancy, including malignant transformation of a benign lesion or development of radiation-associated secondary intracranial cancer, defined as within the 2 Gy isodose line. Estimates of age-adjusted incidence of primary CNS malignancies in the USA and European countries were retrieved from the Central Brain Tumor Registry of the United States (CBTRUS) and the International Agency for Research on Cancer (IARC) Global Cancer statistics. FINDINGS: Of 14 168 patients who had Gamma Knife stereotactic radiosurgery between Aug 14, 1987, and Dec 31, 2011, in the five contributing centres, 4905 patients were eligible for the analysis (had a minimum follow-up of 5 years and no history of previous radiation therapy). Diagnostic entities included vestibular schwannomas (1011 [20·6%] of 4905 patients), meningiomas (1490 [30·4%]), arteriovenous malformations (1089 [22·2%]), trigeminal neuralgia (565 [11·5%]), pituitary adenomas (641 [13·1%]), haemangioblastoma (29 [0·6%]), and other schwannomas (80 [1·6%]). With a median follow-up of 8·1 years (IQR 6·0-10·6), two (0·0006%) of 3251 patients with benign tumours were diagnosed with suspected malignant transformation and one (0·0002%) of 4905 patients was considered a case of radiosurgery-associated intracranial malignancy, resulting in an incidence of 6·87 per 100 000 patient-years (95% CI 1·15-22·71) for malignant transformation and 2·26 per 100 000 patient-years (0·11-11·17) for radiosurgery-associated intracranial malignancy. Two (0·0004%) of 4905 patients developed intracranial malignancies, which were judged unrelated to the radiation field. Overall incidence of radiosurgery-associated malignancy was 6·80 per 100 000 patients-years (95% CI 1·73-18·50), or a cumulative incidence of 0·00045% over 10 years (95% CI 0·00-0·0034). The overall incidence of 6·8 per 100 000, which includes institutions from Europe and the USA, after stereotactic radiosurgery was found to be similar to the risk of developing a malignant CNS tumour in the general population of the USA and some European countries as estimated by the CBTRUS and IARC data, respectively. INTERPRETATION: These data show that the estimated risk of an intracranial secondary malignancy or malignant transformation of a benign tumour in patients treated with stereotactic radiosurgery remains low at long-term follow-up, and is similar to the risk of the general population to have a primary CNS tumour. Although prospective cohort studies with longer follow-up are warranted to support the results of this study, the available evidence suggests the long-term safety of stereotactic radiosurgery and could support physicians counselling patients on Gamma Knife stereotactic radiosurgery. FUNDING: None.

Mortality in Incident Maintenance Dialysis Patients Versus Incident Solid Organ Cancer Patients: A Population-Based Cohort.

RATIONALE & OBJECTIVE: The mortality rate is high among dialysis patients, but how this compares with other diseases such as cancer is poorly understood. We compared the survival of maintenance dialysis patients with that for patients with common cancers to enhance the understanding of the burden of end-stage kidney disease. STUDY DESIGN: Population-based cohort study. SETTING & PARTICIPANTS: 33,500 incident maintenance dialysis patients in Ontario, Canada, and 532,452 incident patients with cancer (women: breast, colorectal, lung, or pancreas; men: prostate, colorectal, lung, or pancreas) from 1997 to 2015 using administrative health care databases. EXPOSURE: Incident kidney failure treated with maintenance dialysis versus incident diagnoses of cancer. OUTCOME: All-cause mortality. ANALYTICAL APPROACH: Kaplan-Meier product limit estimator was used to describe the survival of subgroups of study participants. Extended Cox regression with a Heaviside function was used to compare survival between patients with incident kidney failure treated with maintenance dialysis and individual diagnoses of various incident cancers. RESULTS: In men, dialysis had worse unadjusted 5-year survival (50.8%; 95% CI, 50.1%-51.6%) compared with prostate (83.3%; 95% CI, 83.1%-83.5%) and colorectal (56.1%; 95% CI, 55.7%-56.5%) cancer, but better survival than lung (14.0%; 95% CI, 13.7%-14.3%) and pancreas (9.1%; 95% CI, 8.5%-9.7%) cancer. In women, dialysis had worse unadjusted 5-year survival (49.8%; 95% CI, 48.9%-50.7%) compared with breast (82.1%; 95% CI, 81.9%-82.4%) and colorectal (56.8%; 95% CI, 56.3%-57.2%) cancer, but better survival than lung (19.7%; 95% CI, 19.4%-20.1%) and pancreas (9.4%; 95% CI, 8.9%-10.0%) cancer. After adjusting for clinical characteristics, similar results were found except when examining men and women with lung and pancreas cancer, for which dialysis patients had a higher rate of death 4 or more years after diagnosis. Women and men 70 years and older with incident kidney failure treated with maintenance dialysis had unadjusted 10-year survival probabilities that were comparable to pancreas and lung cancer. LIMITATIONS: Cancer stage could be obtained for only a subpopulation. CONCLUSIONS: Survival in incident dialysis patients was lower than in patients with several different solid-organ cancers. These results highlight the need to develop interventions to improve survival on dialysis therapy and can be used to aid advance care planning for elderly patients beginning treatment with maintenance dialysis.

Venous Thromboembolism and the Risk of Death and Graft Loss in Kidney Transplant Recipients.

BACKGROUND: The implications of venous thromboembolism (VTE) for morbidity and mortality in kidney transplant recipients are not well described. METHODS: We conducted a retrospective study using linked healthcare databases in Ontario, Canada to determine the risk and complications of VTE in kidney transplant recipients from 2003 to 2013. We compared the incidence rate of VTE in recipients (n = 4,343) and a matched (1:4) sample of the general population (n = 17,372). For recipients with evidence of a VTE posttransplant, we compared adverse clinical outcomes (death, graft loss) to matched (1:2) recipients without evidence of a VTE posttransplant. RESULTS: During a median follow-up of 5.2 years, 388 (8.9%) recipients developed a VTE compared to 254 (1.5%) in the matched general population (16.3 vs. 2.4 events per 1,000 person-years; hazard ratio [HR] 7.1, 95% CI 6.0-8.4; p < 0.0001). Recipients who experienced a posttransplant VTE had a higher risk of death (28.5 vs. 11.2%; HR 4.1, 95% CI 2.9-5.8; p < 0.0001) and death-censored graft loss (13.1 vs. 7.5%; HR 2.3, 95% CI 1.4-3.6; p = 0.0006) compared to matched recipients who did not experience a posttransplant VTE. CONCLUSIONS: Kidney transplant recipients have a sevenfold higher risk of VTE compared to the general population with VTE conferring an increased risk of death and graft loss.

Epidemiology of Fracture in Adults from Ontario, Canada, with Chronic Kidney Disease: An Examination of Fracture Burden Using Administrative Health Data.

Fractures are associated with morbidity and mortality. Individuals with chronic kidney disease (CKD) experience bone mineral metabolism changes, which increases fracture risk. Researchers have quantified the epidemiology of fractures in adults with CKD using administrative health databases from Ontario, Canada, held at the Institute for Clinical Evaluative Sciences. Results demonstrated that many individuals with non-transplant CKD sustain fractures, with the risk increasing as kidney function declines. However, fracture risk in kidney transplant recipients was lower than previously described, which suggests recipients may not be a high-risk fracture group. There is a need to test fracture prevention interventions in the CKD population.

Risk of major hemorrhage after kidney transplantation.

BACKGROUND: Major hemorrhagic events are associated with significant morbidity and mortality. We examined the three-year cumulative incidence of hospitalization with major nontraumatic hemorrhage after kidney transplantation. METHODS: We performed a retrospective cohort study using healthcare administrative data of all adult-incident kidney-only transplantation recipients in Ontario, Canada from 1994 to 2009. We calculated the three-year cumulative incidence, event rate, and incident rate ratio of hospitalization with major hemorrhage, its subtypes and those undergoing a hemorrhage-related procedure. RESULTS were stratified by patient age and donor type and compared to a random and propensity-score matched sample from the general population. RESULTS: Among 4,958 kidney transplant recipients, the three-year cumulative incidence of hospitalization with nontraumatic major hemorrhage was 3.5% (95% confidence interval [CI] 3.0-4.1%, 12.7 events per 1,000 patient-years) compared to 0.4% (95% CI 0.4-0.5%) in the general population (RR = 8.2, 95% CI 6.9-9.7). The crude risk of hemorrhage was 3-9-fold higher in all subtypes (upper/lower gastrointestinal, intra-cranial) and 15-fold higher for gastrointestinal endoscopic procedures compared to the random sample from the general population. After propensity score matching, the relative risk for major hemorrhage and its subtypes attenuated but remained elevated. The cumulative incidence of hemorrhage was higher for older individuals and those with a deceased donor kidney. CONCLUSION: Kidney transplantation recipients have a higher risk of hospitalization with hemorrhage compared to the general population, with about 1 in 30 recipients experiencing a major hemorrhage in the three years following transplant.

Calcium channel blocker-clarithromycin drug interaction did not increase the risk of nonvertebral fracture: a population-based study.

BACKGROUND: Calcium channel blocker (CCB) use in elderly patients lowers blood pressure and can increase the risk of falls and fractures. These drugs are metabolized by the cytochrome P450 3A4 (CYP3A4) enzyme, and blood concentrations of these drugs may rise to harmful levels when CYP3A4 activity is inhibited. Clarithromycin is an inhibitor of CYP3A4, whereas azithromycin is not. OBJECTIVE: In older patients taking a CCB, we investigated whether coprescription of clarithromycin, compared with azithromycin, was associated with a higher risk of fracture. METHODS: This was a population-level retrospective cohort study in Ontario, Canada, from 2003 to 2012 of older adults (mean age = 76 years) newly prescribed clarithromycin (n = 96 226) or azithromycin (n = 94 083) while taking a CCB (amlodipine, nifedipine, felodipine, verapamil, diltiazem). The outcome assessed within 30 days of a new coprescription was a nonvertebral fracture. RESULTS: There were no differences in measured baseline characteristics between the clarithromycin and azithromycin groups. Amlodipine was the most commonly prescribed CCB (more than 50% of patients). Coprescribing clarithromycin, versus azithromycin, was not associated with a higher 30-day risk of nonvertebral fracture (124 patients of 96 226 taking clarithromycin [0.13%] vs 98 patients of 94 083 taking azithromycin [0.10%]; odds ratio = 1.23 [95% CI = 0.94-1.60]; P = 0.134). CONCLUSIONS: Among older adults taking a CCB, concurrent use of clarithromycin, compared with azithromycin, was not associated with a statistically significantly greater 30-day risk of nonvertebral fracture.

The three-year incidence of fracture in chronic kidney disease.

Knowing a person's fracture risk according to their kidney function, gender, and age may influence clinical management and decision-making. Using healthcare databases from Ontario, Canada, we conducted a cohort study of 679,114 adults of 40 years and over (mean age 62 years) stratified at cohort entry by estimated glomerular filtration rate ((eGFR) 60 and over, 45-59, 30-44, 15-29, and under 15 ml/min per 1.73 m(2)), gender, and age (40-65 and over 65 years). The primary outcome was the 3-year cumulative incidence of fracture (proportion of adults who fractured (hip, forearm, pelvis, or proximal humerus) at least once within 3-years of follow-up). Additional analyses examined the fracture incidence per 1000 person-years, hip fracture alone, stratification by prior fracture, stratification by eGFR and proteinuria, and 3-year cumulative incidence of falls with hospitalization. The 3-year cumulative incidence of fracture significantly increased in a graded manner in adults with a lower eGFR for both genders and both age groups. The 3-year cumulative incidence of fracture in women over 65 years of age across the 5 eGFR groups were 4.3%, 5.8%, 6.5%, 7.8%, and 9.6%, respectively. Corresponding estimates for men over 65 years were 1.6%, 2.0%, 2.7%, 3.8%, and 5.0%, respectively. Similar graded relationships were found for falls with hospitalization and additional analyses. Thus, many adults with chronic kidney disease will fall and fracture. Results can be used for prognostication and guidance of sample size requirements for fracture prevention trials.

Bone health in living kidney donors.

PURPOSE OF REVIEW: Living kidney donors may experience changes in bone mineral metabolism, which adversely affect the skeletal system. In this review, we summarize the literature assessing the relationship between living kidney donation, changes in bone mineral metabolism, and skeletal fracture. RECENT FINDINGS: Living kidney donor nephrectomy may lower the concentration of 1,25-dihydroxyvitamin D and phosphate and raise the concentration of parathyroid hormone, with no appreciable effect on the concentration of calcium. There is conflicting evidence on whether the concentration of fibroblast growth factor 23 rises after kidney donation. Whether these changes in bone mineral metabolism alter skeletal fracture risk in living kidney donors is an open question. To date, a single study of over 2000 living kidney donors (median age 43 years) matched to a segment of the general population selected for good health has found that after a median follow-up of 6.6 years (maximum 17.7 years), the rate of fragility (osteoporotic) fractures is no higher in donors compared to nondonors. SUMMARY: Living kidney donors experience changes in bone mineral metabolism. Long-term studies are needed to determine whether an association between living kidney donation and fracture exists.

Comparison of COVID-19 Hospitalization and Death Between Solid Organ Transplant Recipients and the General Population in Canada, 2020-2022.

Background: Solid organ transplant recipients have a high risk of severe outcomes from SARS-CoV-2 infection. A comprehensive understanding of the impact of the COVID-19 pandemic across multiple waves in the solid organ transplant population and how this compares to the general population is limited. We conducted a population-based cohort study using linked administrative healthcare databases from Ontario, Canada to answer this question. Methods: We included 15 306 solid organ transplant recipients and 12 160 904 individuals from the general population. Our primary outcome was the rate (per 100 person-years) of severe COVID-19 (ie, hospitalization or death with a positive SARS-CoV-2 test) occurring between January 25, 2020, and November 30, 2022. Results: Compared with the general population, solid organ transplant recipients had almost a 6 times higher rate of severe COVID-19 (20.39 versus 3.44 per 100 person-years), with almost 5.5 times as high a rate of death alone (4.19 versus 0.77 per 100 person-years). Transplant recipients with severe COVID-19 were substantially younger (60.1 versus 66.5 y) and had more comorbidities. The rate of severe COVID-19 declined over time in the solid organ transplant population, with an incidence rate of 41.25 per 100 person-years in the first wave (January 25, 2020, to August 31, 2020) and 18.41 in the seventh wave (June 19, 2022, to November 30, 2022, Omicron era). Conclusions: Solid organ transplant recipients remain at high risk of severe outcomes when they are infected with SARS-CoV-2. Resources and strategies to mitigate the impact of SARS-CoV-2 exposure are needed in this vulnerable patient population.

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.