Association of Low Glomerular Filtration Rate With Adverse Outcomes at Older Age in a Large Population With Routinely Measured Cystatin C.

BACKGROUND: The commonly accepted threshold of glomerular filtration rate (GFR) to define chronic kidney disease (CKD) is less than 60 mL/min/1.73 m2. This threshold is based partly on associations between estimated GFR (eGFR) and the frequency of adverse outcomes. The association is weaker in older adults, which has created disagreement about the appropriateness of the threshold for these persons. In addition, the studies measuring these associations included relatively few outcomes and estimated GFR on the basis of creatinine level (eGFRcr), which may be less accurate in older adults. OBJECTIVE: To evaluate associations in older adults between eGFRcr versus eGFR based on creatinine and cystatin C levels (eGFRcr-cys) and 8 outcomes. DESIGN: Population-based cohort study. SETTING: Stockholm, Sweden, 2010 to 2019. PARTICIPANTS: 82 154 participants aged 65 years or older with outpatient creatinine and cystatin C testing. MEASUREMENTS: Hazard ratios for all-cause mortality, cardiovascular mortality, and kidney failure with replacement therapy (KFRT); incidence rate ratios for recurrent hospitalizations, infection, myocardial infarction or stroke, heart failure, and acute kidney injury. RESULTS: The associations between eGFRcr-cys and outcomes were monotonic, but most associations for eGFRcr were U-shaped. In addition, eGFRcr-cys was more strongly associated with outcomes than eGFRcr. For example, the adjusted hazard ratios for 60 versus 80 mL/min/1.73 m2 for all-cause mortality were 1.2 (95% CI, 1.1 to 1.3) for eGFRcr-cys and 1.0 (CI, 0.9 to 1.0) for eGFRcr, and for KFRT they were 2.6 (CI, 1.2 to 5.8) and 1.4 (CI, 0.7 to 2.8), respectively. Similar findings were observed in subgroups, including those with a urinary albumin-creatinine ratio below 30 mg/g. LIMITATION: No GFR measurements. CONCLUSION: Compared with low eGFRcr in older patients, low eGFRcr-cys was more strongly associated with adverse outcomes and the associations were more uniform. PRIMARY FUNDING SOURCE: Swedish Research Council, National Institutes of Health, and Dutch Kidney Foundation.

A population-based cohort defined risk of hyperkalemia after initiating SGLT-2 inhibitors, GLP1 receptor agonists or DPP-4 inhibitors to patients with chronic kidney disease and type 2 diabetes.

Hyperkalemia is a common adverse event in patients with chronic kidney disease (CKD) and type 2 diabetes and limits the use of guideline-recommended therapies such as renin-angiotensin system inhibitors. Here, we evaluated the comparative effects of sodium-glucose cotransporter-2 inhibitors (SGLT-2i), glucagon-like peptide-1 receptor agonists (GLP-1RA) and dipeptidyl peptidase-4 inhibitors (DPP-4i) on the risk of hyperkalemia. We conducted a population-based active-comparator, new-user cohort study using claims data from Medicare and two large United States commercial insurance databases (April 2013-April 2022). People with CKD stages 3-4 and type 2 diabetes who newly initiated SGLT-2i vs. DPP-4i (141671 patients), GLP-1RA vs. DPP-4i (159545 patients) and SGLT-2i vs. GLP-1RA (93033 patients) were included. The primary outcome was hyperkalemia diagnosed in inpatient or outpatient settings. Secondary outcomes included hyperkalemia diagnosed in inpatient or emergency department setting, and serum potassium levels of 5.5 mmol/L or more. Pooled hazard ratios and rate differences were estimated after propensity score matching to adjust for over 140 potential confounders. Initiation of SGLT-2i was associated with a lower risk of hyperkalemia compared with DPP-4i (hazard ratio 0.74; 95% confidence interval 0.68-0.80) and contrasted to GLP-1RA (0.92; 0.86-0.99). Compared with DPP-4i, GLP-1RA were also associated with a lower risk of hyperkalemia (0.80; 0.75-0.86). Corresponding absolute rate differences/1000 person-years were -24.8 (95% confidence interval -31.8 to -17.7), -5.0 (-10.9 to 0.8), and -17.7 (-23.4 to -12.1), respectively. Similar findings were observed for the secondary outcomes, among subgroups, and across single agents within the SGLT-2i and GLP-1RA classes. Thus, SGLT-2i and GLP-1RA are associated with a lower risk of hyperkalemia than DPP-4i in patients with CKD and type 2 diabetes, further supporting the use of these drugs in this population.

Comparative Safety and Effectiveness of Warfarin or Rivaroxaban Versus Apixaban in Patients With Advanced CKD and Atrial Fibrillation: Nationwide US Cohort Study.

RATIONALE & OBJECTIVE: Head-to-head data comparing the effectiveness and safety of oral anticoagulants in patients with atrial fibrillation (AF) and advanced chronic kidney disease (CKD) are lacking. We compared the safety and effectiveness of warfarin or rivaroxaban versus apixaban in patients with AF and non-dialysis-dependent CKD stage 4/5. STUDY DESIGN: Propensity score-matched cohort study. SETTING & PARTICIPANTS: 2 nationwide US claims databases, Medicare and Optum's deidentified Clinformatics Data Mart Database, were searched for the interval from January 1, 2013, through March 31, 2022, for patients with nonvalvular AF and CKD stage 4/5 who initiated warfarin versus apixaban (matched cohort, n=12,488) and rivaroxaban versus apixaban (matched cohort, n = 5,720). EXPOSURES: Warfarin, rivaroxaban, or apixaban. OUTCOMES: Primary outcomes included major bleeding and ischemic stroke. Secondary outcomes included all-cause mortality, major gastrointestinal bleeding, and intracranial bleeding. ANALYTICAL APPROACH: Cox regression was used to estimate HRs, and 1:1 propensity-score matching was used to adjust for 80 potential confounders. RESULTS: Compared with apixaban, warfarin initiation was associated with a higher rate of major bleeding (HR, 1.85; 95% CI, 1.59-2.15), including major gastrointestinal bleeding (1.86; 1.53-2.25) and intracranial bleeding (2.15; 1.42-3.25). Compared with apixaban, rivaroxaban was also associated with a higher rate of major bleeding (1.69; 1.33-2.15). All-cause mortality was similar for warfarin (1.08; 0.98-1.18) and rivaroxaban (0.94; 0.81-1.10) versus apixaban. Furthermore, no statistically significant differences for ischemic stroke were observed for warfarin (1.14; 0.83-1.57) or rivaroxaban (0.71; 0.40-1.24) versus apixaban, but the CIs were wide. Similar results were observed for warfarin versus apixaban in the positive control cohort of patients with CKD stage 3, consistent with randomized trial findings. LIMITATIONS: Few ischemic stroke events, potential residual confounding. CONCLUSIONS: In patients with AF and advanced CKD, rivaroxaban and warfarin were associated with higher rates of major bleeding compared with apixaban, suggesting a superior safety profile for apixaban in this high-risk population. PLAIN-LANGUAGE SUMMARY: Different anticoagulants have been shown to reduce the risk of stroke in patients with atrial fibrillation, such as warfarin and direct oral anticoagulants like apixaban and rivaroxaban. Unfortunately, the large-scale randomized trials that compared direct anticoagulants versus warfarin excluded patients with advanced chronic kidney disease. Therefore, the comparative safety and effectiveness of warfarin, apixaban, and rivaroxaban are uncertain in this population. In this study, we used administrative claims data from the United States to answer this question. We found that warfarin and rivaroxaban were associated with increased risks of major bleeding compared with apixaban. There were few stroke events, with no major differences among the 3 drugs in the risk of stroke. In conclusion, this study suggests that apixaban has a better safety profile than warfarin and rivaroxaban.

Accuracy of GFR estimating equations based on creatinine, cystatin C or both in routine care.

BACKGROUND: New equations to estimate glomerular filtration rate based on creatinine (eGFRcr), cystatin C (eGFRcys) or both (eGFRcr-cys) have been developed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and the European Kidney Function Consortium (EKFC). There is a need to evaluate the performance of these equations in diverse European settings to inform implementation decisions, especially among people with key comorbid conditions. METHODS: We performed a cross-sectional study including 6174 adults referred for single-point plasma clearance of iohexol in Stockholm, Sweden, with 9579 concurrent measurements of creatinine and cystatin C. We assessed the performance of the CKD-EPI 2009/2012/2021, EKFC 2021/2023, revised Lund-Malmö (RLM) 2011 and Caucasian, Asian, Pediatric and Adult (CAPA) 2014 equations against measured GFR (mGFR). RESULTS: Mean age was 56 years, median mGFR was 62 mL/min/1.73 m2 and 40% were female. Comorbid conditions were common: cardiovascular disease (30%), liver disease (28%), diabetes (26%) and cancer (26%). All eGFRcr-cys equations had small bias and P30 (the percentage of estimated values within 30% of mGFR) close to 90%, and performed better than eGFRcr or eGFRcys equations. Among eGFRcr equations, CKD-EPI 2009 and CKD-EPI 2021 showed larger bias and lower P30 than EKFC 2021 and RLM. There were no meaningful differences in performance across eGFRcys equations. Findings were consistent across comorbid conditions, and eGFRcr-cys equations showed good performance in patients with liver disease, cancer and heart failure. CONCLUSIONS: In conclusion, eGFRcr-cys equations performed best, with minimal variation among equations in this Swedish cohort. The lower performance of CKD-EPI eGFRcr equations compared with EKFC and RLM may reflect differences in population characteristics and mGFR methods. Implementing eGFRcr equations will require a trade-off between accuracy and uniformity across regions.

Target Trial Emulation to Improve Causal Inference from Observational Data: What, Why, and How?

ABSTRACT: Target trial emulation has drastically improved the quality of observational studies investigating the effects of interventions. Its ability to prevent avoidable biases that have plagued many observational analyses has contributed to its recent popularity. This review explains what target trial emulation is, why it should be the standard approach for causal observational studies that investigate interventions, and how to do a target trial emulation analysis. We discuss the merits of target trial emulation compared with often used, but biased analyses, as well as potential caveats, and provide clinicians and researchers with the tools to better interpret results from observational studies investigating the effects of interventions.

Accuracy of GFR Estimating Equations in Patients with Discordances between Creatinine and Cystatin C-Based Estimations.

SIGNIFICANCE STATEMENT: Large discordances between eGFR on the basis of creatinine (eGFR cr ) or cystatin C (eGFR cys ) are common in clinical practice. However, which GFR estimating equation (eGFR cr , eGFR cys , or eGFR cr-cys ) is most accurate in these settings is not known. In this real-world study of 9404 concurrent measurements of creatinine, cystatin C, and iohexol clearance, all three equations performed similarly when eGFR cr and eGFR cys were similar (45% of cases). However, with large discordances (55% of cases), eGFR cr-cys was much more accurate than either alone. These findings were consistent among individuals with cardiovascular disease, heart failure, diabetes mellitus, liver disease, and cancer who have been underrepresented in research cohorts. Thus, when eGFR cr and eGFR cys are largely discordant in clinical practice, eGFR cr-cys is more accurate than eGFR cr or eGFR cys . BACKGROUND: Cystatin C is recommended as a confirmatory test to eGFR when more precise estimates are needed for clinical decision making. Although eGFR on the basis of both creatinine and cystatin (eGFR cr-cys ) is the most accurate estimate in research studies, it is uncertain whether this is true in real-world settings, particularly when there are large discordances between eGFR based on creatinine (eGFR cr ) and that based on cystatin C (eGFR cys ). METHODS: We included 6185 adults referred for measured GFR (mGFR) using plasma clearance of iohexol in Stockholm, Sweden, who had 9404 concurrent measurements of creatinine, cystatin C, and iohexol clearance. The performance of eGFR cr , eGFR cys , and eGFR cr-cys was assessed against mGFR with median bias, P30 , and correct classification of GFR categories. We stratified analyses within three categories: eGFR cys at least 20% lower than eGFR cr (eGFR cys eGFR cr ). RESULTS: eGFR cr and eGFR cys were similar in 4226 (45%) samples, and among these samples all three estimating equations performed similarly. By contrast, eGFR cr-cys was much more accurate in cases of discordance. For example, when eGFR cys eGFR cr (8% of samples), the median biases were -4.5, 8.4, and 1.4 ml/min per 1.73m 2 . The findings were consistent among individuals with cardiovascular disease, heart failure, diabetes mellitus, liver disease, and cancer. CONCLUSIONS: When eGFR cr and eGFR cys are highly discordant in clinical practice, eGFR cr-cys is more accurate than either eGFR cr or eGFR cys .

Sodium-glucose cotransporter 2 inhibitors vs. sitagliptin in heart failure and type 2 diabetes: an observational cohort study.

AIMS: The effectiveness of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in patients with heart failure (HF) in routine clinical practice is not extensively studied. This study aimed to evaluate the comparative effectiveness of SGLT2i vs. sitagliptin in older adults with HF and type 2 diabetes and to investigate whether there were any differences between agents within the SGLT2i class or for reduced and preserved ejection fraction. METHODS AND RESULTS: Using Medicare claims data (April 2013 to December 2019), 16 253 SGLT2i initiators vs. 43 352 initiators of sitagliptin aged ≥65 years with type 2 diabetes and HF were included. The primary outcome was a composite of all-cause mortality, hospitalization for HF or urgent visit requiring intravenous diuretics; secondary outcomes included its individual components. Propensity score fine stratification weighted Cox regression was used to adjust for 100 pre-exposure characteristics. Mean age was 74 years; 49.8% were women. Initiation of SGLT2i vs. sitagliptin was associated with a lower risk of the primary composite outcome [adjusted hazard ratio (HR) 0.72; 95% confidence interval 0.67-0.77]. The adjusted HRs were 0.70 (0.63-0.78) for all-cause mortality, 0.64 (0.58-0.70) for hospitalization for HF, and 0.77 (0.69-0.86) for urgent visit requiring intravenous diuretics. Similar associations with the primary composite outcome were observed for all three agents within the SGLT2i class, for reduced and preserved ejection fraction, and subgroups based on demographics, comorbidities, and other HF treatments. Bias-calibrated HRs for the primary endpoint using negative and positive control outcomes ranged between 0.81 and 0.89, suggesting that the observed benefit could not be fully explained by residual confounding. CONCLUSION: In routine US clinical practice, SGLT2i demonstrated robust clinical effectiveness in older adults with HF and type 2 diabetes compared with sitagliptin, with no evidence of heterogeneity across the SGLT2i class or across ejection fraction.

Finerenone in chronic kidney disease and type 2 diabetes: the known and the unknown.

The novel nonsteroidal mineralocorticoid receptor antagonist finerenone has been shown to reduce the risk of kidney and cardiovascular outcomes in patients with type 2 diabetes and chronic kidney disease. In this issue of Kidney International, Bakris et al. present new data on the kidney efficacy of finerenone across subgroups of estimated glomerular filtration rate and urinary albumin-to-creatinine ratio, as well as safety data. We attempt to place these results in context by discussing the benefits and risks of finerenone, as well as the generalizability of the study findings to routine care settings.

A nationwide cohort study comparing the effectiveness of diuretics and calcium channel blockers on top of renin-angiotensin system inhibitors on chronic kidney disease progression and mortality.

It is unknown whether initiating diuretics on top of renin-angiotensin system inhibitors (RASi) is superior to alternative antihypertensive agents such as calcium channel blockers (CCBs) in patients with chronic kidney disease (CKD). For this purpose, we emulated a target trial in the Swedish Renal Registry 2007-2022 that included nephrologist-referred patients with moderate-advanced CKD and treated with RASi, who initiated diuretics or CCB. Using propensity score-weighted cause-specific Cox regression, we compared risks of major adverse kidney events (MAKE; composite of kidney replacement therapy [KRT], experiencing over a 40% eGFR decline from baseline, or an eGFR under 15 ml/min per 1.73m2), major cardiovascular events (MACE; composite of cardiovascular death, myocardial infarction or stroke), and all-cause mortality. We identified 5875 patients (median age 71 years, 64% men, median eGFR 26 ml/min per 1.73m2), of whom 3165 started a diuretic and 2710 a CCB. After a median follow-up of 6.3 years, 2558 MAKE, 1178 MACE and 2299 deaths occurred. Compared to CCB, diuretic use was associated with a lower risk of MAKE (weighted hazard ratio 0.87 [95% confidence interval: 0.77-0.97]), consistent across single components (KRT: 0.77 [0.66-0.88], over 40% eGFR decline: 0.80 [0.71-0.91] and eGFR under 15ml/min/1.73m2: 0.84 [0.74-0.96]). The risks of MACE (1.14 [0.96-1.36]) and all-cause mortality (1.07 [0.94-1.23]) did not differ between therapies. Results were consistent when modeling the total time drug exposure, across sub-groups and a broad range of sensitivity analyses. Thus, our observational study suggests that in patients with advanced CKD, using a diuretic rather than a CCB on top of RASi may improve kidney outcomes without compromising cardioprotection.

Association between cholinesterase inhibitors and kidney function decline in patients with Alzheimer's dementia.

Preclinical evidence shows that activation of the cholinergic anti-inflammatory pathway (CAP) may have direct and indirect beneficial effects on the kidney. Cholinesterase inhibitors (ChEIs) are specific Alzheimer's dementia (AD) therapies that block the action of cholinesterases and activate CAP. Here, we explored a plausible effect of ChEIs on slowing kidney function decline by comparing the risk of CKD progression among patients with newly diagnosed AD that initiated ChEI or not within 90 days. Using complete information of routine serum creatinine tests, we evaluated changes in estimated glomerular filtration rate (eGFR) and defined the outcome of chronic kidney disease (CKD) progression as the composite of an eGFR decline of over 30%, initiation of dialysis/transplant or death attributed to CKD. A secondary outcome was death. Inverse probability of treatment-weighted Cox regression was used to estimate hazard ratios. Among 11, 898 patients, 6,803 started on ChEIs and 5,095 did not. Mean age was 80 years (64% women) and the mean eGFR was 68 ml/min/1.73m2. During a median 3.0 years of follow-up, and compared to non-use, ChEI use was associated with 18% lower risk of CKD progression (1,231 events, adjusted hazard ratio 0.82; 95% confidence interval 0.71-0.96) and a 21% lower risk of death (0.79; 0.72-0.86). Results were consistent across subgroups, ChEI subclasses and after accounting for competing risks. Thus, in patients with AD undergoing routine care, use of ChEI (vs no-use) was associated with lower risk of CKD progression.

Defining measures of kidney function in observational studies using routine health care data: methodological and reporting considerations.

The availability of electronic health records and access to a large number of routine measurements of serum creatinine and urinary albumin enhance the possibilities for epidemiologic research in kidney disease. However, the frequency of health care use and laboratory testing is determined by health status and indication, imposing certain challenges when identifying patients with kidney injury or disease, when using markers of kidney function as covariates, or when evaluating kidney outcomes. Depending on the specific research question, this may influence the interpretation, generalizability, and/or validity of study results. This review illustrates the heterogeneity of working definitions of kidney disease in the scientific literature and discusses advantages and limitations of the most commonly used approaches using 3 examples. We summarize ways to identify and overcome possible biases and conclude by proposing a framework for reporting definitions of exposures and outcomes in studies of kidney disease using routinely collected health care data.

Long-term Visit-to-Visit Variability in Hemoglobin A1c and Kidney-Related Outcomes in Persons With Diabetes.

RATIONALE & OBJECTIVE: To characterize associations between long-term visit-to-visit variability of hemoglobin A1c (HbA1c) and risk of adverse kidney outcomes in patients with diabetes. STUDY DESIGN: Observational study. SETTING & PARTICIPANTS: 93,598 adults with diabetes undergoing routine care in Stockholm, Sweden. EXPOSURES AND PREDICTORS: Categories of baseline and time-varying HbA1c variability score (HVS, the percentage of total HbA1c measures that vary by>0.5% [5.5mmol/mol] during a 3-year window): 0-20%, 21%-40%, 41%-60%, 61%-80%, and 81%-100%, with 0-20% as the reference group. OUTCOME: Chronic kidney disease (CKD) progression (composite of>50% estimated glomerular filtration rate [eGFR] decline and kidney failure), acute kidney disease (AKI by clinical diagnosis or transient creatinine elevations according to KDIGO criteria), and worsening of albuminuria. ANALYTICAL APPROACH: Multivariable Cox proportional hazards regression. RESULTS: Compared with persons showing low HbA1c variability (HVS 0-20%), any increase in variability was associated with a higher risk of adverse kidney outcomes beyond mean HbA1c. For example, for patients with a baseline HbA1c variability of 81%-100%, the adjusted HR was 1.6 (95% CI, 1.47-1.74) for CKD progression, 1.23 [1.16-1.3] for AKI, and 1.28 [1.21-1.36] for worsening of albuminuria. The results were consistent across subgroups (diabetes subtypes, baseline eGFR, or albuminuria categories), in time-varying analyses and in sensitivity analyses including time-weighted average HbA1c or alternative metrics of variability. LIMITATIONS: Observational study, limitations of claims data, lack of information on diet, body mass index, medication changes, and diabetes duration. CONCLUSIONS: Higher long-term visit-to-visit HbA1c variability is consistently associated with the risks of CKD progression, AKI, and worsening of albuminuria. PLAIN-LANGUAGE SUMMARY: The evidence for current guideline recommendations derives from clinical trials that focus on a single HbA1c as the definitive measure of efficacy of an intervention. However, long-term visit-to-visit fluctuations of HbA1c may provide additional value in the prediction of future kidney complications. We evaluated the long-term fluctuations in glycemic control in almost 100,000 persons with diabetes undergoing routine care in Stockholm, Sweden. We observed that higher long-term HbA1c fluctuation is consistently associated with the risks of chronic kidney disease progression, worsening of albuminuria and acute kidney injury. This finding supports a role for long-term glycemic variability in the development of kidney complications and illustrates the potential usefulness of this metric for risk stratification at the bedside beyond a single HbA1c test.

Cardiorenal Outcomes Among Patients With Atrial Fibrillation Treated With Oral Anticoagulants.

RATIONALE & OBJECTIVE: Direct oral anticoagulants (DOACs) have progressively replaced vitamin K antagonists (VKAs) for stroke prevention in patients with nonvalvular atrial fibrillation (AF). DOACs cause fewer bleeding complications, but their other advantages, particularly related to kidney outcomes, remain inconclusive. We studied the risks of chronic kidney disease (CKD) progression and acute kidney injury (AKI) after DOAC and VKA administration for nonvalvular AF. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Cohort study of Swedish patients enrolled in the Stockholm Creatinine Measurements (SCREAM) project with a diagnosis of nonvalvular AF during 2011-2018. EXPOSURE: Initiation of DOAC or VKA treatment. OUTCOME: Primary outcomes were CKD progression (composite of >30% estimated glomerular filtration rate [eGFR] decline and kidney failure) and AKI (by diagnosis or KDIGO-defined transient creatinine elevations). Secondary outcomes were death, major bleeding, and the composite of stroke and systemic embolism. ANALYTICAL APPROACH: Propensity score weighted Cox regression was used to balance 50 baseline confounders. Sensitivity analyses included falsification end points, subgroups, and estimation of per-protocol effects. RESULTS: We included 32,699 patients (56% initiated DOAC) who were observed for a median of 3.8 years. Their median age was 75 years, 45% were women, and 27% had an eGFR <60mL/min/1.73m2. The adjusted HRs for DOAC versus VKA were 0.87 (95% CI, 0.78-0.98) for the risk of CKD progression and 0.88 (95% CI, 0.80-0.97) for AKI. HRs were 0.77 (95% CI, 0.67-0.89) for major bleeding, 0.93 (95% CI, 0.78-1.11) for the composite of stroke and systemic embolism, and 1.04 (95% CI, 0.95-1.14) for death. The results were similar across subgroups of age, sex, and baseline eGFR when restricting to patients at high risk for thromboembolic events and when censoring follow up at treatment discontinuation or change in type of anticoagulation. LIMITATIONS: Missing information on time in therapeutic range and treatment dosages. CONCLUSIONS: Among patients with nonvalvular AF treated in routine clinical practice compared with VKA use, DOAC use was associated with a lower risk of CKD progression, AKI, and major bleeding but a similar risk of the composite of stroke, systemic embolism, or death.

Discordances Between Creatinine- and Cystatin C-Based Estimated GFR and Adverse Clinical Outcomes in Routine Clinical Practice.

RATIONALE & OBJECTIVE: Cystatin C is recommended for measuring estimated glomerular filtration rate (eGFR) when estimates based on creatinine (eGFRcr) are not thought to be accurate enough for clinical decision making. While global adoption is slow, routine cystatin C testing in Sweden has been available for over a decade, providing real-world evidence about the magnitude of differences between eGFRcys and eGFRcr and their association with clinical outcomes. STUDY DESIGN: Observational study. SETTING & PARTICIPANTS: 158,601 adults (48% women; mean age 62 years, eGFRcr 80, and eGFRcys 73mL/min/1.73/m2) undergoing testing for creatinine and cystatin C on the same day in connection with a health care encounter during 2010-2018 in Stockholm, Sweden. EXPOSURE: Percentage difference of eGFRcys minus eGFRcr (eGFRdiff). OUTCOME: Kidney failure with replacement therapy (KFRT), acute kidney injury (AKI), atherosclerotic cardiovascular disease (ASCVD), heart failure, and death. ANALYTICAL APPROACH: Multivariable Cox proportional hazards regression. RESULTS: Discordances between eGFRcr and eGFRcys were common, with eGFRcys being lower than eGFRcr (negative eGFRdiff) in most cases (65%). Patients with larger negative eGFRdiff were older, more often female, with higher eGFRcr and albuminuria, and more comorbid conditions. Compared with patients with similar eGFRcys and eGFRcr, the lowest quartile (eGFRcys > 27% lower than eGFRcr) had the higher HR of all study outcomes: AKI, 2.6 (95% CI, 2.4-2.9); KFRT, 1.4 (95% CI, 1.2-1.6); ASCVD, 1.4 (95% CI, 1.3-1.5); heart failure, 2.0 (95% CI, 1.9-2.2); and all-cause death, 2.6 (95% CI, 2.5-2.7). Conversely, patients in the highest quartile (positive eGFRdiff) were at lower risk. LIMITATIONS: Observational study, lack of information on indications for cystatin C testing. CONCLUSIONS: Cystatin C testing in routine care shows that many patients have a lower eGFRcys than eGFRcr, and these patients have a higher risk of multiple adverse outcomes. PLAIN-LANGUAGE SUMMARY: Clinicians require guidance when there are discrepancies between the estimated glomerular filtration rate based on creatinine (eGFRcr) and based on cystatin C (eGFRcys) in the same individual. Routine cystatin C testing in Sweden for over a decade permits exploration of how common and large these discrepancies are, and their associations with adverse clinical outcomes. In this observational study, we found that discordances between eGFRcys and eGFRcr are common, and 1 in 4 patients tested had an eGFRcys > 28% lower than their eGFRcr. We also show that an eGFRcys that is lower than the eGFRcr consistently identifies patients at higher risk of adverse outcomes, including cardiovascular events, kidney replacement therapy, acute kidney injury, and death.

Risk of Acute Kidney Injury Among Older Adults With Heart Failure and With Reduced Ejection Fraction Treated With Angiotensin-Neprilysin Inhibitor vs Renin-Angiotensin System Inhibitor in Routine Clinical Care.

BACKGROUND: The acute hemodynamic effects of sacubitril/valsartan, an angiotensin receptor neprilysin inhibitor (ARNI), may result in early changes in kidney function, raising concerns about acute kidney injury (AKI), particularly in those who are naïve to renin-angiotensin system inhibitors (RASis). METHODS: We conducted a cohort study using U.S. Medicare fee-for-service claims data (2014-2017). Patients with HFrEF ≥ 65 years newly initiating ARNI or RASi, with no prior use of either drug class, were included. The primary outcome was hospitalization due to AKI as the primary discharge diagnosis, and the secondary outcome included AKI as a primary or secondary discharge diagnosis. AKI risks were described under an as-treated follow-up approach, with censoring on treatment discontinuation, switch, insurance disenrollment, death, or administrative censoring as well as an intent-to-treat approach. Propensity-score-based fine-stratification weighting was used to account for potential confounding by 81 pre-exposure characteristics. Cumulative incidence functions were used to report absolute risks, and Cox proportional hazards models were used to provide hazard ratios (HR) and 95% confidence intervals (CI). RESULTS: We included 27,166 patients with a mean (SD) age of 73 (7.3) years, and 4155 (15.3%) were initiating ARNI. After propensity score weighting, the 180-day cumulative incidence was 2.7% (2.4%-3.1%) among RASi initiators and 2.7% (2.2%-3.5%) among ARNI initiators for the primary outcome, and it was 6.5% (6.0%-7.1%) and 6.1% (5.2%-7.1%), respectively, for the secondary outcome under as-treated follow-up. HR (95% CI) comparing ARNI with RASi were 0.91 (95% CI: 0.72-1.16) for the primary outcome and 0.92 (95% CI: 0.79-1.08) for the secondary outcome. Similar results were observed in the intent-to-treat analysis. CONCLUSIONS: Among a large cohort of U.S. Medicare beneficiaries with HFrEF, ARNI treatment was not associated with higher rates of AKI than RASi treatment. These results provide reassurance for providers considering ARNI initiation in older patients who are RASi-naïve.

Removing race from the CKD-EPI equation and its impact on prognosis in a predominantly White European population.

BACKGROUND: While American nephrology societies recommend using the 2021 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (eGFR) equation without a Black race coefficient, it is unknown how this would impact disease distribution, prognosis and kidney failure risk prediction in predominantly White non-US populations. METHODS: We studied 1.6 million Stockholm adults with serum/plasma creatinine measurements between 2007 and 2019. We calculated changes in eGFR and reclassification across KDIGO GFR categories when changing from the 2009 to 2021 CKD-EPI equation; estimated associations between eGFR and the clinical outcomes kidney failure with replacement therapy (KFRT), (cardiovascular) mortality and major adverse cardiovascular events using Cox regression; and investigated prognostic accuracy (discrimination and calibration) of both equations within the Kidney Failure Risk Equation. RESULTS: Compared with the 2009 equation, the 2021 equation yielded a higher eGFR by a median [interquartile range (IQR)] of 3.9 (2.9-4.8) mL/min/1.73 m2, which was larger at older age and for men. Consequently, 9.9% of the total population and 36.2% of the population with CKD G3a-G5 was reclassified to a higher eGFR category. Reclassified individuals exhibited a lower risk of KFRT, but higher risks of all-cause/cardiovascular death and major adverse cardiovascular events, compared with non-reclassified participants of similar eGFR. eGFR by both equations strongly predicted study outcomes, with equal discrimination and calibration for the Kidney Failure Risk Equation. CONCLUSIONS: Implementing the 2021 CKD-EPI equation in predominantly White European populations would raise eGFR by a modest amount (larger at older age and in men) and shift a major proportion of CKD patients to a higher eGFR category. eGFR by both equations strongly predicted outcomes.

Sex Differences in the Recognition, Monitoring, and Management of CKD in Health Care: An Observational Cohort Study.

INTRODUCTION: Reported sex differences in the etiology, population prevalence, progression rates, and health outcomes of people with CKD may be explained by differences in health care. METHODS: We evaluated sex as the variable of interest in a health care-based study of adults (n=227,847) with at least one outpatient eGFR<60 ml/min per 1.73 m2 measurement denoting probable CKD in Stockholm from 2009 to 2017. We calculated the odds ratios for diagnosis of CKD and provision of RASi and statins at inclusion, and hazard ratios for CKD diagnosis, visiting a nephrologist, or monitoring creatinine and albuminuria during follow-up. RESULTS: We identified 227,847 subjects, of whom 126,289 were women (55%). At inclusion, women had lower odds of having received a diagnostic code for CKD and were less likely to have received RASi and statins, despite having guideline-recommended indications. In time-to-event analyses, women were less likely to have received a CKD diagnosis (HR, 0.43; 95% CI, 0.42 to 0.45) and visited a nephrologist (HR, 0.46; 95% CI, 0.43 to 0.48) regardless of disease severity, presence of albuminuria, or criteria for referral. Women were also less likely to undergo monitoring of creatinine or albuminuria, including those with diabetes or hypertension. These differences remained after adjustment for comorbidities, albuminuria, and highest educational achievement, and among subjects with confirmed CKD at retesting. Although in absolute terms all nephrology-care indicators gradually improved over time, the observed sex gap persisted. CONCLUSIONS: There were profound sex differences in the detection, recognition, monitoring, referrals, and management of CKD. The disparity was also observed in people at high risk and among those who had guideline-recommended indications. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/JASN/2022_10_11_JASN2022030373.mp3.

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.

GLP-1 receptor agonist versus DPP-4 inhibitor and kidney and cardiovascular outcomes in clinical practice in type-2 diabetes.

Whether glucagon-like peptide-1 receptor agonists (GLP1-RA) reduce detrimental kidney outcomes is uncertain. In secondary analyses, trials have shown consistent reductions in macroalbuminuria, but inconclusive results about kidney function decline. To help clarify this, we conducted a cohort study to compare kidney and cardiovascular outcomes in individuals who started GLP1-RA or dipeptidyl peptidase-4 inhibitors (DPP4i) (reduces degradation of endogenous GLP1). The primary outcome was a composite of sustained doubling of creatinine, kidney failure or kidney death. The secondary outcomes were three-point major adverse cardiovascular events (MACE) and its individual components. Propensity score weighted Cox regression was used to balance 53 confounders. A total of 19,766 individuals were included, of whom 5,699 initiated GLP1-RA, and were followed for a median 2.9 years. Mean age was 63 years, 26.2% had atherosclerotic cardiovascular disease and 16.0% had an estimated glomerular filtration rate (eGFR) under 60 ml/min/1.73m2. The adjusted hazard ratio for GLP1-RA vs. DPP4i was 0.72 (95% confidence interval 0.53-0.98) for the composite kidney outcome and 0.85 (0.73-0.99) for MACE, with absolute five-year risk reductions of 0.8% (0.1%-1.5%) and 1.6% (0.2%-2.9%), respectively. Hazard ratios were 0.79 (0.60-1.05) for cardiovascular death, 0.86 (0.68-1.09) for myocardial infarction and 0.74 (0.59-0.93) for stroke. Results were consistent within subgroups, including age, sex, eGFR and baseline metformin use. Thus, in our analysis of patients from routine clinical practice, the use of GLP1-RA was associated with a lower risk of kidney outcomes compared with DPP4i. Reductions in both kidney outcomes and MACE were similar in magnitude to those reported in large cardiovascular outcome trials.

Stopping renin-angiotensin system inhibitors after hyperkalemia and risk of adverse outcomes.

BACKGROUND: Stopping renin-angiotensin system inhibitors (RASi) after an episode of hyperkalemia is common but may involve therapeutic compromises, in that the cessation of RASi deprives patients of their beneficial cardiovascular effects. METHODS AND RESULTS: Observational study from the Stockholm Creatinine Measurements (SCREAM) project including patients initiating RASi in routine care and surviving a first-detected episode of hyperkalemia (potassium >5.0 mmol/L). We used target trial emulation techniques based on cloning, censoring and weighting to compare stopping vs. continuing RASi within 6 months after hyperkalemia. Outcomes were 3-year risks of mortality, major adverse cardiovascular events (MACE, composite of cardiovascular death, myocardial infarction and stroke hospitalization) and recurrent hyperkalemia. Of 5669 new users of RASi who developed hyperkalemia (median age 72 years, 44% women), 1425 (25%) stopped RASi therapy within 6 months. Compared with continuing RASi, stopping therapy was associated with a higher 3-year risk of death (absolute risk difference 10.8%; HR 1.49, 95% CI 1.34-1.64) and MACE (risk difference 4.7%; HR 1.29, 1.14-1.45), but a lower risk of recurrent hyperkalemia (risk difference -9.5%; HR 0.76, 0.69-0.84). Results were consistent for events following potassium of >5.0 or >5.5 mmol/L, after censoring when the treatment decision was changed, across prespecified subgroups, and after adjusting for albuminuria. CONCLUSION: These findings suggest that stopping RASi after hyperkalemia may be associated with a lower risk of recurrence of hyperkalemia, but higher risk of death and cardiovascular events.