Iohexol plasma clearance measurement protocol standardization for adults: a consensus paper of the European Kidney Function Consortium.

International consensus supports the development of standardized protocols for measured glomerular filtration rate (mGFR) to facilitate the integration of mGFR testing in both clinical and research settings. To this end, the European Kidney Function Consortium convened an international group of experts with relevant experience in mGFR. The working group performed an extensive literature search to inform the development of recommendations for mGFR determination using 1-compartment plasma clearance models and iohexol as the exogenous filtration marker. Iohexol was selected as it is non-radio labeled, inexpensive, and safe, can be assayed at a central laboratory, and the other commonly used non-radio-labeled tracers have been (inulin) or are soon to be (iothalamate) discontinued. A plasma clearance model was selected over urine clearance as it requires no urine collection. A 1 compartment was preferred to 2 compartments as it requires fewer samples. The recommendations are based on published evidence complemented by expert opinion. The consensus paper covers practical advice for patients and health professionals, preparation, administration, and safety aspects of iohexol, laboratory analysis, blood sample collection and sampling times using both multiple and single-sample protocols, description of the mGFR mathematical calculations, as well as implementation strategies. Supplementary materials include patient and provider information sheets, standard operating procedures, a study protocol template, and support for mGFR calculation.

Social support and frailty progression in community-dwelling older adults.

Objectives: Despite the growing evidence regarding the influence of social factors on frailty in older adults, the effect of social support remains unclear. This study aims to assess the association between social support and frailty progression (transition and incidence) in a sample of community-dwelling older adults. Methods: Using a cohort study design, 1,059 older adults from the Berlin Initiative Study were followed up for 2.1 years. Multinomial and logistic regression analyses were performed to assess the association of social support using Oslo Social Support Scale-3 with frailty transition and incidence, respectively. Gender differences were explored using stratified analyses. Results: At baseline, frailty prevalence in the study population [mean (SD) age 84.3 (5.6) years; 55.8% women] reached 33.1% with 47.0, 29.4 and 23.6% of the participants reporting moderate, strong and poor social support, respectively. Over the follow-up period, social support was not significantly associated with the frailty transition categories in the adjusted model. Conversely, the adjusted logistic regression analysis showed that participants with poor social support had twice the odds of becoming frail compared to those with strong social support (OR 2.07; 95% CI 1.08-3.95). Gender-stratified analyses showed comparable estimates to the main analysis but were statistically non-significant. Discussion: Our study results underpin the role of social factors in frailty incidence and highlight social support as a potential target for frailty-preventing interventions in older adults. Therefore, it is important to adopt a biopsychosocial model rather than a purely biomedical model to understand and holistically improve the health of community-dwelling older adults.

Diabetic status and the performances of creatinine- and cystatin C-based eGFR equations.

BACKGROUND AND HYPOTHESIS: The estimation of glomerular filtration rate (GFR) is one main tool to detect renal disease. The most used biomarker remains serum creatinine and the European Kidney Function Consortium (EKFCcrea) equation is the most validated in Europe. More recently, cystatin C, has been proposed. We studied the performances of the EKFC equations in a large cohort of subjects according to their diabetic status. METHODS: Four cohorts from the EKFC dataset were retrospectively considered in which the diabetic status was available. GFR was measured by plasma clearances (mGFR) (iohexol or 51Cr-EDTA). The performance of the equations was assessed by calculating bias, precision (IQR) and P30 (percentage of eGFR-values within ± 30% of mGFR). RESULTS: In the whole population (n = 6 158), median [IQR] age was 61 [47;72] years, with 45.8% women. Mean mGFR was 60 [39;82] mL/min/1.73m². Compared to non-diabetic individuals (n = 5 124), diabetic patients (n = 1 034) were older, more frequently male, heavier, and had lower mGFR. The performance of the EKFCcys equation was similar to EKFCcrea, but the EKFCcrea+cys had better P30 than the single-biomarker equations. P30 values were substantially lower in diabetic patients than in non-diabetic but, according to a matched analysis, this is mainly explained by the difference in GFR levels between the two populations, not by diabetic status. CONCLUSION: We showed that equation combining creatinine and cystatin C present a better performance. If accuracy of equations seems better in non-diabetic than in diabetic individuals, it is more due to differences in GFR levels than to the diabetic status.

Effect modification of polypharmacy on incident frailty by chronic kidney disease in older adults.

BACKGROUND: Frailty and polypharmacy are common conditions in older adults, especially in those with chronic kidney disease (CKD). Therefore, we analyzed the association of polypharmacy and incident frailty and the effect modification by CKD in very old adults. METHODS: In non-frail individuals within the Berlin Initiative (cohort) Study, polypharmacy (≥ 5 medications) was assessed according to multiple definitions based on the number of regular and on demand prescription and over the counter drugs, as well as vitamins and supplements. CKD was defined as an estimated glomerular filtration rate < 60 mL/min/1.73m2 and/or an albumin-creatinine ratio ≥ 30 mg/g. Incident frailty was assessed at follow-up using Fried criteria. Logistic regression was applied to assess (1) the association of different polypharmacy definitions with incident frailty and (2) effect modification by CKD. RESULTS: In this cohort study, out of 757 non-frail participants (mean age 82.9 years, 52% female, 74% CKD), 298 (39%) participants reported polypharmacy. Over the observation period of 2.1 years, 105 became frail. Individuals with polypharmacy had 1.96 adjusted odds (95% confidence interval (CI): 1.20-3.19) of becoming frail compared to participants without polypharmacy. The effect of polypharmacy on incident frailty was modified by CKD on the additive scale (relative excess risk due to interaction: 1.56; 95% CI 0.01-3.12). CONCLUSIONS: This study demonstrates an association of polypharmacy and incident frailty and suggests strong evidence for an effect modification of CKD on polypharmacy and incident frailty. Revision of prescriptions could be a target strategy to prevent frailty occurrence, especially in older adults with CKD.

The Lack of a Standardized Definition of Chronic Dialysis Treatment in German Statutory Health Insurance Claims Data.

BACKGROUND: Chronic kidney failure (CKF) is often treated with dialysis, which is invasive and costly and carries major medical risks. The existing studies of patients with CKF requiring dialysis that are based on claims data from German statutory health insurance (SHI) carriers employ varying definitions of this entity, with unclear consequences for the resulting statistical estimates. METHODS: We carried out a cohort study on four random samples, each consisting of 62 200 persons aged 70 or above, from among the insurees of the SHI AOK Nordost, with one sample for each of the years 2012, 2014, 2016, and 2018. The prevalence, incidence, mortality, and direct health care costs of CKF requiring dialysis were estimated and compared on the basis of four different definitions from literature and a new definition developed by the authors in reference to billing data. RESULTS: The different definitions led to variation in 12-month prevalences (range: 0.33-0.61%) and 6-month incidences (0.058-0.100%). The percentage of patients with prior acute kidney injury (AKI) ranged from 27.6% to 61.8%. Among incident patients, three-month survival ranged from 70.2% to 88.1%, and six-month survival from 60.5% to 81.3%. In CKF patients without prior AKI, the survival curves differed less across definitions (80.2-91.8% at three months, 70.7-84.4% at six months). The monthly health care costs ranged from €6010 to €9606, with marked variability across definitions in the costs of inpatient and outpatient care. CONCLUSION: The lack of a standardized definition of CKF requiring dialysis in German SHI claims data leads to variability in the estimated case numbers, mortality, and health care costs. These differences are most probably in part due to the variable inclusion of inpatients who received short-term dialysis after AKI.

Diagnostic Validity of Chronic Kidney Disease in Health Claims Data Over Time: Results from a Cohort of Community-Dwelling Older Adults in Germany.

Purpose: The validity of ICD-10 diagnostic codes for chronic kidney disease (CKD) in health claims data has not been sufficiently studied in the general population and over time. Patients and Methods: We used data from the Berlin Initiative Study (BIS), a prospective longitudinal cohort of community-dwelling individuals aged ≥70 years in Berlin, Germany. With estimated glomerular filtration rate (eGFR) as reference, we assessed the diagnostic validity (sensitivity, specificity, positive [PPV], and negative predictive values [NPV]) of different claims-based ICD-10 codes for CKD stages G3-5 (eGFR <60mL/min/1.73m²: ICD-10 N18.x-N19), G3 (eGFR 30-<60mL/min/1.73m²: N18.3), and G4-5 (eGFR <30mL/min/1.73m²: N18.4-5). We analysed trends over five study visits (2009-2019). Results: We included data of 2068 participants at baseline (2009-2011) and 870 at follow-up 4 (2018-2019), of whom 784 (38.9%) and 440 (50.6%) had CKD G3-5, respectively. At baseline, sensitivity for CKD in claims data ranged from 0.25 (95%-confidence interval [CI] 0.22-0.28) to 0.51 (95%-CI 0.48-0.55) for G3-5, depending on the included ICD-10 codes, 0.20 (95%-CI 0.18-0.24) for G3, and 0.36 (95%-CI 0.25-0.49) for G4-5. Over the course of 10 years, sensitivity increased by 0.17 to 0.29 in all groups. Specificity, PPVs, and NPVs remained mostly stable over time and ranged from 0.82-0.99, 0.47-0.89, and 0.66-0.98 across all study visits, respectively. Conclusion: German claims data showed overall agreeable performance in identifying older adults with CKD, while differentiation between stages was limited. Our results suggest increasing sensitivity over time possibly attributable to improved CKD diagnosis and awareness.

[Novel equations for estimating renal function: significance for drug dose adjustment]. / Neue Formeln zur Schätzung der Nierenfunktion ­ Bedeutung für die Dosierung nierengängiger Arzneimittel.

BACKGROUND: Important therapeutic decisions depend on kidney function, which is why its correct assessment is of great importance. It also plays an important role for drug dose adjustments in patients with impaired kidney function. OBJECTIVES: In clinical practice, kidney function is almost always estimated using mathematical glomerular filtration rate (GFR) equations. To estimate GFR, the patient's age and gender as well as kidney-specific endogenous biomarkers are required. This work aims to provide an overview of the advantages and disadvantages of the biomarkers serum creatinine and cystatin C in assessing kidney function. Particularly in patients with significantly reduced or increased muscle mass, creatinine is not suitable for determining GFR, and cystatin C should be used. Currently recommended GFR estimating equations are described, illustrating for which patient groups they can be used. CURRENT DATA: A large number of high-ranking publications are available investigating the validity of GFR estimating equations and the optimal choice of endogenous biomarkers. However, there are still large gaps when it comes to drug approval studies in older patients and children. CONCLUSION: Estimated GFR (eGFR) is only a rough estimate of kidney function and should not be interpreted as an exact number. Drug dose adjustments may be necessary in patients with an eGFR of < 50 ml/min and should be verified particularly in severely impaired GFR (< 30 ml/min). There are tools available online for this purpose.

Kidney function estimators for drug dose adjustment of direct oral anticoagulants in older adults with atrial fibrillation.

Background: The Cockcroft-Gault equation (CrClC-G) is recommended for dose adjustment of direct oral anticoagulant drugs (DOACs) to kidney function. We aimed to assess whether defining DOAC dose appropriateness according to various kidney function estimators changed the associations between dose appropriateness and adverse events in older adults with atrial fibrillation (AF). Methods: Participants of the Berlin Initiative Study with AF and treated with DOACs were included. We investigated CrClC-G and estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration and European Kidney Function Consortium equations based on creatinine and/or cystatin C. Marginal structural Cox models yielded confounder-adjusted hazard ratios for the risk of mortality, thromboembolism and bleeding associated with dose status. Results: A total of 224 patients were included in the analysis (median age 87 years). Using CrClC-G, 154 (69%) had an appropriate dose of DOACs, 52 (23%) were underdosed and 18 (8%) were overdosed. During a 39-month median follow-up period, 109 (14.9/100 person-years) participants died, 25 (3.6/100 person-years) experienced thromboembolism and 60 (9.8/100 person-years) experienced bleeding. Dose status was not associated with mortality and thromboembolism, independent of the equation. Underdose status was associated with a lower risk of bleeding with all the equations compared with the appropriate dose group. In participants with discrepancies in dose status using CrClC-G and eGFR equations, the occurrence of endpoints did not differ between participants having an appropriate dose using CrClC-G or eGFR. Conclusion: In older adults with AF, the association of DOAC dose status with adverse events did not differ when using CrClC-G or eGFR. Our results suggest that eGFR equations are not inferior to CrClC-G within this context.

Regional Variation in Hemoglobin Distribution Among Individuals With CKD: the ISN International Network of CKD Cohorts.

Introduction: Despite recognized geographic and sex-based differences in hemoglobin in the general population, these factors are typically ignored in patients with chronic kidney disease (CKD) in whom a single therapeutic range for hemoglobin is recommended. We sought to compare the distribution of hemoglobin across international nondialysis CKD populations and evaluate predictors of hemoglobin. Methods: In this cross-sectional study, hemoglobin distribution was evaluated in each cohort overall and stratified by sex and estimated glomerular filtration rate (eGFR). Relationships between candidate predictors and hemoglobin were assessed from linear regression models in each cohort. Estimates were subsequently pooled in a random effects model. Results: A total of 58,613 participants from 21 adult cohorts (median eGFR range of 17-49 ml/min) and 3 pediatric cohorts (median eGFR range of 26-45 ml/min) were included with broad geographic representation. Hemoglobin values varied substantially among the cohorts, overall and within eGFR categories, with particularly low mean hemoglobin observed in women from Asian and African cohorts. Across the eGFR range, women had a lower hemoglobin compared to men, even at an eGFR of 15 ml/min (mean difference 5.3 g/l, 95% confidence interval [CI] 3.7-6.9). Lower eGFR, female sex, older age, lower body mass index, and diabetic kidney disease were all independent predictors of a lower hemoglobin value; however, this only explained a minority of variance (R2 7%-44% across cohorts). Conclusion: There are substantial regional differences in hemoglobin distribution among individuals with CKD, and the majority of variance is unexplained by demographics, eGFR, or comorbidities. These findings call for a renewed interest in improving our understanding of hemoglobin determinants in specific CKD populations.

Estimated Glomerular Filtration Rate, Albuminuria, and Adverse Outcomes: An Individual-Participant Data Meta-Analysis.

Importance: Chronic kidney disease (low estimated glomerular filtration rate [eGFR] or albuminuria) affects approximately 14% of adults in the US. Objective: To evaluate associations of lower eGFR based on creatinine alone, lower eGFR based on creatinine combined with cystatin C, and more severe albuminuria with adverse kidney outcomes, cardiovascular outcomes, and other health outcomes. Design, Setting, and Participants: Individual-participant data meta-analysis of 27 503 140 individuals from 114 global cohorts (eGFR based on creatinine alone) and 720 736 individuals from 20 cohorts (eGFR based on creatinine and cystatin C) and 9 067 753 individuals from 114 cohorts (albuminuria) from 1980 to 2021. Exposures: The Chronic Kidney Disease Epidemiology Collaboration 2021 equations for eGFR based on creatinine alone and eGFR based on creatinine and cystatin C; and albuminuria estimated as urine albumin to creatinine ratio (UACR). Main Outcomes and Measures: The risk of kidney failure requiring replacement therapy, all-cause mortality, cardiovascular mortality, acute kidney injury, any hospitalization, coronary heart disease, stroke, heart failure, atrial fibrillation, and peripheral artery disease. The analyses were performed within each cohort and summarized with random-effects meta-analyses. Results: Within the population using eGFR based on creatinine alone (mean age, 54 years [SD, 17 years]; 51% were women; mean follow-up time, 4.8 years [SD, 3.3 years]), the mean eGFR was 90 mL/min/1.73 m2 (SD, 22 mL/min/1.73 m2) and the median UACR was 11 mg/g (IQR, 8-16 mg/g). Within the population using eGFR based on creatinine and cystatin C (mean age, 59 years [SD, 12 years]; 53% were women; mean follow-up time, 10.8 years [SD, 4.1 years]), the mean eGFR was 88 mL/min/1.73 m2 (SD, 22 mL/min/1.73 m2) and the median UACR was 9 mg/g (IQR, 6-18 mg/g). Lower eGFR (whether based on creatinine alone or based on creatinine and cystatin C) and higher UACR were each significantly associated with higher risk for each of the 10 adverse outcomes, including those in the mildest categories of chronic kidney disease. For example, among people with a UACR less than 10 mg/g, an eGFR of 45 to 59 mL/min/1.73 m2 based on creatinine alone was associated with significantly higher hospitalization rates compared with an eGFR of 90 to 104 mL/min/1.73 m2 (adjusted hazard ratio, 1.3 [95% CI, 1.2-1.3]; 161 vs 79 events per 1000 person-years; excess absolute risk, 22 events per 1000 person-years [95% CI, 19-25 events per 1000 person-years]). Conclusions and Relevance: In this retrospective analysis of 114 cohorts, lower eGFR based on creatinine alone, lower eGFR based on creatinine and cystatin C, and more severe UACR were each associated with increased rates of 10 adverse outcomes, including adverse kidney outcomes, cardiovascular diseases, and hospitalizations.

Incidence of hospital-acquired acute kidney injury and trajectories of glomerular filtration rate in older adults.

BACKGROUND: In older adults, epidemiological data on incidence rates (IR) of hospital-acquired acute kidney injury (AKI) are scarce. Also, little is known about trajectories of kidney function before hospitalization with AKI. METHODS: We used data from biennial face-to-face study visits from the prospective Berlin Initiative Study (BIS) including community-dwelling participants aged 70+ with repeat estimated glomerular filtration rate (eGFR) based on serum creatinine and cystatin C. Primary outcome was first incident of hospital-acquired AKI assessed through linked insurance claims data. In a nested case-control study, kidney function decline prior to hospitalization with and without AKI was investigated using eGFR trajectories estimated with mixed-effects models adjusted for traditional cardiovascular comorbidities. RESULTS: Out of 2020 study participants (52.9% women; mean age 80.4 years) without prior AKI, 383 developed a first incident AKI, 1518 were hospitalized without AKI, and 119 were never hospitalized during a median follow-up of 8.8 years. IR per 1000 person years for hospital-acquired AKI was 26.8 (95% confidence interval (CI): 24.1-29.6); higher for men than women (33.9 (29.5-38.7) vs. 21.2 (18.1-24.6)). IR (CI) were lowest for persons aged 70-75 (13.1; 10.0-16.8) and highest for ≥ 90 years (54.6; 40.0-72.9). eGFR trajectories declined more steeply in men and women with AKI compared to men and women without AKI years before hospitalization. These differences in eGFR trajectories remained after adjustment for traditional comorbidities. CONCLUSION: AKI is a frequent in-hospital complication in individuals aged 70 + showing a striking increase of IR with age. eGFR decline was steeper in elderly patients with AKI compared to elderly patients without AKI years prior to hospitalization emphasising the need for long-term kidney function monitoring pre-admission to improve risk stratification.

Prospective mixed-methods study evaluating the potential of a voicebot (CovBot) to relieve German health authorities during the COVID-19 infodemic.

Background: During the COVID-19 pandemic, telephone hotlines of local health authorities in Germany were overloaded due to information requests by the public. Objective: Evaluating the use of a COVID-19-specific voicebot (CovBot) in local health authorities in Germany during the COVID-19 pandemic. This study investigates the performance of the CovBot by assessing a perceptible relief of staff in the hotline service. Methods: This prospective mixed-methods study enrolled local health authorities in Germany from 01 February 2021 to 11 February 2022 to deploy the CovBot, which was mainly designed to answer frequently asked questions. To capture the user perspective and acceptance, we performed semistructured interviews and online surveys with their staff, conducted an online survey among callers, and analyzed the performance metrics of the CovBot. Results: The CovBot was implemented in 20 local health authorities serving 6.1 million German citizens and processed almost 1.2 million calls during the study period. The overall assessment was that the CovBot contributed to a perceived relief of the hotline service. In a survey among callers, 79% indicated that a voicebot could not replace a human. The analyzed anonymous metadata revealed that 15% of calls hung up immediately, 32% after hearing an FAQ answer, and 51% of calls were forwarded to the local health authority offices. Conclusions: A voicebot primarily answering FAQs can provide additional support to relieve the hotline service of local health authorities in Germany during the COVID-19 pandemic. For complex concerns, a forwarding option to a human proved to be an essential functionality.

Estimated GFR Accuracy When Cystatin C- and Creatinine-Based Estimates Are Discrepant in Older Adults.

Rationale & Objective: Serum creatinine and cystatin C are used to estimate glomerular filtration rate, but creatinine-based estimated glomerular filtration rate (eGFRcr), cystatin C-based estimated glomerular filtration rate (eGFRcys), and combined creatinine- and cystatin C-based estimated glomerular filtration rate (eGFRcr-cys) are often divergent, particularly in older adults. We investigated which estimated glomerular filtration rate (eGFR) was more accurate and less biased compared with measured glomerular filtration rate (mGFR). Study Design: A diagnostic test study from the Berlin Initiative Study. Setting & Participants: The study population included 657 individuals aged 70 years or older with iohexol plasma clearance (mGFR) and serum creatinine and cystatin C measurements: 567 community-dwelling participants and 90 with a serum creatinine of ≥1.5 mg/dL. Tests Compared: We defined 3 groups on the basis of the difference eGFRcys - eGFRcr: whether < -5 mL/min/1.73 m2 (lower eGFRcys), within 5 mL/min/1.73 m2 (reference), or ≥ 5 mL/min/1.73 m2 (lower eGFRcr). eGFRcr, eGFRcys, and eGFRcr-cys were compared to mGFR to assess bias and accuracy. Outcome: Median bias (eGFR minus mGFR) with 95% CIs and accuracy (percentage of eGFR values within ±30% of mGFR). Results: The mean ± standard deviation age was 78 ± 6 years; the mean eGFRcys, eGFRcr, and eGFRcr-cys were 59 ± 23, 64 ± 20, and 61 ± 22 mL/min/1.73 m2, respectively, and the mean mGFR was 56 ± 19 mL/min. Half of the participants were in the lower eGFRcys group (n=337, 51%). Among them, the median bias for eGFRcys was the lowest (median bias, -2.7; 95% CI, -3.8 to -1.9) compared with the other eGFR equations. Conversely, in the lower eGFRcr group (n=121, 18%), the median bias for eGFRcr was the lowest compared with those for eGFRcys and eGFRcr-cys (2.9; [95% CI, 0.9-4.8] vs 13.8 [95% CI, 11.4-15.6] and 9.5 [95% CI, 7.7-11.0], respectively). Accuracy (percentage of eGFR values within ±30% of mGFR) was 93% for eGFRcr in the lower eGFRcr group and 92% for eGFRcys and 94% for eGFRcr-cys in the lower eGFRcys group. Limitations: Untested generalizability in younger populations. Conclusions: Among older adults, the lower eGFR between eGFRcys and eGFRcr was a more accurate and less biased estimate of mGFR when comparing the groups.

Association of kidney function and albuminuria with frailty worsening and death in very old adults.

BACKGROUND AND OBJECTIVES: Studies analysing the association of albuminuria and prevalent frailty in community-dwelling very old adults are scarce and lack information on incident frailty. We investigated the association of kidney function decline and increase of albuminuria with frailty worsening or death in very old adults. DESIGN: Longitudinal analyses with biennial visits of the Berlin Initiative (cohort) Study and a frailty follow-up of 2.1 years. SETTING/SUBJECTS: 1,076 participants with a mean age of 84.3 (5.6) years of whom 54% were female. METHODS: Partial proportional odds models were used to assess the association of estimated glomerular filtration rate (eGFR) decline and/or albuminuria (albumin creatinine ratio, ACR) with frailty worsening or death. RESULTS: At frailty baseline, 1,076 participants with an eGFR of 50 (13) ml/min/1.73 m2, 48% being prefrail and 31% frail were included. After median 2.1 years, 960 (90%) participants had valid information on frailty transition: 187 (17.5%) worsened and 111 (10.3%) died. In the multivariable model, the odds of frailty worsening for participants with albuminuria in combination with eGFR <60 ml/min/1.73 m2 were elevated [OR (95% CI): 2.47 (1.41-4.31)] compared to participants without albuminuria and eGFR ≥60 ml/min/1.73 m2 as there was a rapid eGFR decline of ≥3 ml/min/1.73 m2 per year [1.55 (1.04-2.33)] and albuminuria trajectories six years prior [1.53 (1.11-2.10)] to frailty baseline. The odds of death for each exposure were even higher. CONCLUSIONS: In older adults, advanced stages of CKD and albuminuria alone were associated with 2-fold odds of frailty worsening independent of death.

[Development of quality indicators for the care of patients with chronic kidney disease : Results of a structured consensus process using the Delphi technique]. / Entwicklung von Qualitätsindikatoren für die Versorgung von Patient:innen mit chronischer Nierenerkrankung : Ergebnisse einer strukturierten Konsensfindung mittels Delphi-Verfahrens.

BACKGROUND: Chronic kidney disease (CKD) is a common condition, especially in the elderly. In order to prevent progression and complications of the disease, guideline-adherent outpatient care of patients with CKD should be prioritized. Quality indicators (QIs) can be used to measure and evaluate the quality of ambulatory care for patients with CKD. QIs specifically made for evaluating CKD care in Germany are not yet available. The goal of this work was to develop QIs for the quality assessment of outpatient care for patients over the age of 70 with CKD not requiring dialysis. MATERIALS AND METHODS: QIs were operationalized from the recommendations of the German national guideline for CKD and others were proposed based on a published review of international QIs. The resulting QIs were divided into sets based on routine data (e.g., health insurance billing data) and data collection in practices (chart review). A panel of experts from various disciplines as well as a patient representative evaluated the proposed QIs in a two-stage Delphi process via online survey in October 2021 and January 2022 and a final consensus conference in March 2022. In addition, ranking lists of the most important QIs from each set were created. RESULTS: An incidence indicator and a prevalence indicator were established; these were not subject to vote. Further, 21 QIs were voted upon by the expert panel. The seven most important QIs in each set (billing data or chart review) were selected. Only one QI was rated by the expert panel as not suitable for additional use in adults under the age of 70 years. DISCUSSION: The QIs will enable the evaluation of the quality of outpatient care for patients with CKD with the long-term aim of optimizing guideline-adherent outpatient care.

Polypharmacy and the Change of Self-Rated Health in Community-Dwelling Older Adults.

Polypharmacy is associated with poorer self-rated health (SRH). However, whether polypharmacy has an impact on the SRH progression is unknown. This study investigates the association of polypharmacy with SRH change in 1428 participants of the Berlin Initiative Study aged 70 years and older over four years. Polypharmacy was defined as the intake of ≥5 medications. Descriptive statistics of SRH-change categories stratified by polypharmacy status were reported. The association of polypharmacy with being in SRH change categories was assessed using multinomial regression analysis. At baseline, mean age was 79.1 (6.1) years, 54.0% were females, and prevalence of polypharmacy was 47.1%. Participants with polypharmacy were older and had more comorbidities compared to those without polypharmacy. Over four years, five SRH-change categories were identified. After covariate adjustment, individuals with polypharmacy had higher odds of being in the stable moderate category (OR 3.55; 95% CI [2.43-5.20]), stable low category (OR 3.32; 95% CI [1.65-6.70]), decline category (OR 1.87; 95% CI [1.34-2.62]), and improvement category (OR 2.01; [1.33-3.05]) compared to being in the stable high category independent of the number of comorbidities. Reducing polypharmacy could be an impactful strategy to foster favorable SRH progression in old age.

Cystatin C-Based Equation to Estimate GFR without the Inclusion of Race and Sex.

BACKGROUND: The accuracy of estimation of kidney function with the use of routine metabolic tests, such as measurement of the serum creatinine level, has been controversial. The European Kidney Function Consortium (EKFC) developed a creatinine-based equation (EKFC eGFRcr) to estimate the glomerular filtration rate (GFR) with a rescaled serum creatinine level (i.e., the serum creatinine level is divided by the median serum creatinine level among healthy persons to control for variation related to differences in age, sex, or race). Whether a cystatin C-based EKFC equation would increase the accuracy of estimated GFR is unknown. METHODS: We used data from patients in Sweden to estimate the rescaling factor for the cystatin C level in adults. We then replaced rescaled serum creatinine in the EKFC eGFRcr equation with rescaled cystatin C, and we validated the resulting EKFC eGFRcys equation in cohorts of White patients and Black patients in Europe, the United States, and Africa, according to measured GFR, levels of serum creatinine and cystatin C, age, and sex. RESULTS: On the basis of data from 227,643 patients in Sweden, the rescaling factor for cystatin C was estimated at 0.83 for men and women younger than 50 years of age and 0.83 + 0.005 × (age - 50) for those 50 years of age or older. The EKFC eGFRcys equation was unbiased, had accuracy that was similar to that of the EKFC eGFRcr equation in both White patients and Black patients (11,231 patients from Europe, 1093 from the United States, and 508 from Africa), and was more accurate than the Chronic Kidney Disease Epidemiology Collaboration eGFRcys equation recommended by Kidney Disease: Improving Global Outcomes. The arithmetic mean of EKFC eGFRcr and EKFC eGFRcys further improved the accuracy of estimated GFR over estimates from either biomarker equation alone. CONCLUSIONS: The EKFC eGFRcys equation had the same mathematical form as the EKFC eGFRcr equation, but it had a scaling factor for cystatin C that did not differ according to race or sex. In cohorts from Europe, the United States, and Africa, this equation improved the accuracy of GFR assessment over that of commonly used equations. (Funded by the Swedish Research Council.).