Prevalence and Characteristics of CKD in the US Military Health System: A Retrospective Cohort Study

Rationale & Objective: The US Military Health System (MHS) is a global health care network with a diverse population that is more representative of the US population than other study cohorts and with fewer disparities in health care access. We aimed to examine the prevalence of chronic kidney disease (CKD) in the MHS and within demographic subpopulations. Study Design: Multiple cross-sectional analyses of demographic and claims-based data extracted from the MHS Data Repository, 1 for each fiscal year from 2006-2015. Setting & Population: Multicenter health care network including active-duty military, retirees, and dependents. The average yearly sample size was 3,285,348 individuals. Exposures: Age, sex, race, active-duty status, and active-duty rank (a surrogate for socioeconomic status). Outcome: CKD, defined as the presence of matching International Classification of Diseases, Ninth Revision , codes on either 1 or more inpatient or 2 or more outpatient encounters. Analytical Approach: t test for continuous variables and chi 2 test for categorical variables; multi -variable logistic regression for odds ratios. Results: For 2015, the mean (standard deviation) age was 38 (16). Crude CKD prevalence was 2.9%. Age-adjusted prevalence was 4.9% overall-1.9% active-duty and 5.4% non-active-duty individuals. ORs for CKD were calculated with multiple imputations to account for missing data on race. After adjustment, the ORs for CKD (all P < 0.001) were 1.63 (95% CI, 1.62-1.6 4) for an age greater than 40 years, 1.16 (95% CI, 1.15-1.17) for Black race, 1.15 (95% CI, 1.14-1.16) for senior enlisted rank, 0.94 (95% CI, 0.93-0.95) for women, and 0.50 (95% CI, 0.4 9-0.51) for active-duty status. Limitations: Retrospective study based on Inter-national Classification of Diseases, Ninth Revision , coding. Conclusions: Within the MHS, older age, Black race, and senior enlisted rank were associated with a higher risk of CKD, whereas female sex and active-duty status were associated with a lower risk.