Kidney Failure Attributed to Immunoglobulin A Nephropathy: A USRDS Retrospective Cohort Study of Epidemiology, Treatment Modalities, and Economic Burden

Abstract

Rationale & ObjectiveThis study describes the epidemiology, characteristics, and outcomes of patients with immunoglobulin A nephropathy (IgAN)-attributed kidney failure in the US Renal Data System (USRDS) during 2008-2018, including healthcare resource utilization and costs among patients with Medicare-linked data. Study DesignRetrospective cohort study Setting & PopulationPatients with IgAN-attributed kidney failure in the USRDS OutcomesPrevalence/incidence, clinical/demographic characteristics, time to kidney transplant; healthcare resource utilization and costs Analytical ApproachPatients with IgAN as primary cause of kidney failure (IgAN cohort) were followed from USRDS registration (index date) until data end/death. Prevalence/incidence were calculated per 1,000,000 US persons. Demographic and clinical characteristics at index and treatment modality during follow-up were summarized. Time from index to kidney transplant was assessed using Kaplan-Meier and competing risk analyses. Healthcare resource utilization and healthcare costs were reported among patients with 1 year Medicare Part A+B coverage post-index, including or excluding those who died (Medicare Coverage and 1-year Medicare Coverage subgroups, respectively). ResultsThe IgAN cohort, Medicare Coverage, and 1-year Medicare Coverage subgroups included 10,101, 1,696, and 1,510 patients, respectively. Mean annual period prevalence and incidence of IgAN-attributed kidney failure were 39.3 and 2.9 per 1,000,000 US persons, respectively. Initial treatment was in-center hemodialysis (63.1%) or kidney transplant (15.1%). Year 1 and 5 kidney transplant rates were 5% and 17%, respectively, accounting for competing risk of death. In the Medicare Coverage and 1-year Medicare Coverage subgroups, 74.4% and 72.3%, respectively, required inpatient admission, 67.3% and 64.4% visited the emergency room, and mean total healthcare costs were $6,293 (SD: $6,934) and $5,284 ($3,455) per-patient-per-month in the year post-index. LimitationsDrug costs may be underestimated as Medicare-Part D coverage was not required; kidney acquisition costs were unavailable. ConclusionsIgAN-attributed kidney failure is associated with substantial clinical and economic burdens. Novel therapies for IgAN that delay kidney failure are needed.