Clinical and Military Outcomes of Kidney Diseases Diagnosed in Active Duty Service Members

Abstract

Introduction Renal biopsy is a valuable tool for determining diagnosis, management, and prognosis of intrinsic kidney diseases. Indications for biopsy depend on the clinical presentation. Within the military, renal biopsies also enable medical review boards to make military service fitness assessments after diagnosis of a kidney disease. There are no recent studies evaluating kidney disease diagnoses and clinical outcomes after renal biopsy at military treatment facilities. Additionally, no studies have examined overall healthcare and military career outcomes following renal biopsy. Materials and Methods We retrospectively reviewed all native renal biopsies performed on active duty beneficiaries at the Walter Reed National Military Medical Center from 2005 to 2020. We determined the prevalence of those who progressed to end-stage kidney disease (ESKD), kidney transplantation, doubling of serum creatinine, nephrotic-range proteinuria (NRP; proteinuria >3.5 g/day), medical evaluation board (MEB) outcomes, and death. The Armed Forces Health Longitudinal Technology Application and the Joint Legacy Viewer electronic medical record systems were used to access clinical and laboratory data at the time of biopsy and subsequent outcomes. Death data were collected using the Defense Suicide Prevention Office database. Results There were 169 patients in the cohort, with a mean follow-up of 7.3 years. Mean age was 32 years; 79% male; 48% white; and 37% black. Sixty-seven percentage of them were junior or senior enlisted. The most common indication for renal biopsy was concomitant hematuria and proteinuria (31%). The most common histologic diagnoses were immunoglobulin A (IgA) nephropathy (23%), followed by focal segmental glomerulosclerosis (FSGS; 17%) and lupus nephritis (12%). Eleven percentage of them progressed to ESKD, of whom 87% received a kidney transplant (10% overall). Thirty percentage of the patients progressed to NRP and 5% died. Forty-seven percentage of our patients underwent MEB after diagnosis, and of these, 84% were not retained for further military service. Although IgA nephropathy was the most commonly diagnosed condition, FSGS and lupus nephritis diagnoses were significantly more likely to result in MEB. Conclusions and Implications Immunoglobulin A nephropathy was the most frequent histologic diagnosis in active duty service members undergoing renal biopsy between 2005 and 2020. Despite being largely young and previously healthy, 11% progressed to ESKD and 5% died. A confirmed histologic diagnosis was associated with separation from the service and the end of military careers for 84% of the patients in the cohort who underwent MEB.