Supplementary Material for: Disparities in Chronic Kidney Disease Progression by Medicare Advantage Enrollees

Introduction: The prevalence of chronic kidney disease (CKD) in Medicare beneficiaries has quadrupled in the past 2 decades, but little is known about risk factors affecting the progression of CKD. This study aims to understand the progression in Medicare Advantage enrollees and whether it differs by provider recognition of CKD, race and ethnicity, or geographic location. In a large cohort of Medicare Advantage (MA) enrollees, we examined whether CKD progression, up to 5 years after study entry, differed by demographic and clinical factors and identified additional risk factors of CKD progression. Methods: In a cohort of 1,002,388 MA enrollees with CKD stages 1–4 based on 2013–2018 labs, progression was estimated using a mixed-effects model that adjusted for demographics, geographic location, comorbidity, urine albumin-to-creatinine ratio, clinical recognition via diagnosed CKD, and time-fixed effects. Race and ethnicity, geographic location, and clinical recognition of CKD were interacted with time in 3 separate regression models. Results: Mean (median) follow-up was 3.1 (3.0) years. Black and Hispanic MA enrollees had greater kidney function at study entry than other beneficiaries, but their kidney function declined faster. MA enrollees with clinically recognized CKD had estimated glomerular filtration rate levels that were 18.6 units (95% confidence interval [CI]: 18.5–18.7) lower than levels of unrecognized patients, but kidney function declined more slowly in enrollees with clinical recognition. There were no differences in CKD progression by geography. After removal of the race coefficient from the eGFR equation in a sensitivity analysis, kidney function was much lower in all years among Black MA enrollees, but patterns of progression remained the same. Discussion/Conclusions: These results suggest that patients with clinically recognized CKD and racial and ethnic minorities merit closer surveillance and management to reduce their risk of faster progression.