Racial and Socioeconomic Disparities in CKD in the Context of Universal Healthcare Provided by the Military Health System

Abstract Rationale & Objective Health-impeding social determinants of health—including reduced access to care—contribute to racial and socioeconomic disparities in chronic kidney disease (CKD). The Military Health System (MHS) provides an opportunity to assess a large, diverse population for CKD disparities in the context of universal healthcare. Study design Cross sectional Setting & Participants MHS beneficiaries aged 18 to 64 receiving care between October 1, 2015 and September 30, 2018. Predictors race, sponsor's rank (a proxy for socioeconomic status and social class), median household income by sponsor's zip code, and marital status Outcome CKD prevalence, defined by ICD-10 codes and/or validated, laboratory value-based electronic phenotype. Analytical Approach Multivariable logistic regression compared CKD prevalence by predictors, controlling separately for confounders (age, sex, active duty status, sponsor's service branch, and depression) and mediators (hypertension, diabetes, HIV and BMI). Results Of 3,330,893 beneficiaries, 105,504 (3.2%) had CKD. In confounder-adjusted models, CKD prevalence was higher in Black vs white beneficiaries (OR = 1.67, 95% confidence interval [CI]: 1.64 - 1.70), but lower in single vs married beneficiaries (OR = 0.77, 95% CI: 0.76 – 0.79). Prevalence of CKD was increased among those with lower military rank and among those with lower median household income in a nearly dose response fashion (p Limitations Cross-sectional design prevents causal inferences. We may have underestimated CKD prevalence, given lack of data for labs conducted outside the MHS and use of a specific CKD definition. The transient nature of the MHS population may limit accuracy of zip code level median household income data. Conclusions Racial and socioeconomic CKD disparities exist in the MHS despite universal healthcare coverage. The existence of CKD disparities by rank and median household income suggest social risks may contribute to both racial and socioeconomic disparities despite access to universal healthcare coverage.