Prevalence of Renal Impairment in a US Commercially Insured Rheumatoid Arthritis Population: A Retrospective Analysis

Introduction Global prevalence estimates for chronic kidney disease (CKD) in rheumatoid arthritis (RA) vary. This study assessed real-world prevalence estimates of renal impairment, based on estimated glomerular filtration rate (eGFR), among commercially insured patients with RA in the United States (US). Methods In this retrospective cohort study, we used administrative claims data from the HealthCore Integrated Research Database (HIRD®) between January 2013 and December 2018. Adult patients with ≥ 2 claims for RA and ≥ 2 serum creatinine (SCr) measurements ≥ 90 days apart on or after the index date were included. eGFR was calculated per the Modification of Diet in Renal Disease equation. Prevalence of eGFR-based renal impairment was estimated for the overall RA population and for two subgroups: patients on advanced therapies (biologic disease-modifying antirheumatic drugs/tofacitinib) and patients stratified based on health plan types. Results Among 128,062 patients with ≥ 2 RA claims, 42,173 had qualifying SCr measurements, 16,197 were on advanced RA therapies, and 4911 had Medicare Advantage or Supplemental plus Part D coverage. For the overall population and the subgroup on advanced therapies, mild renal impairment was observed in 52% and 51%, moderate renal impairment in 9% and 7%, and severe renal impairment in 0.5% and 0.3% of patients, respectively. Moderate and severe renal impairment was more prevalent in the Medicare Advantage/Supplemental plus Part D population compared to the commercial coverage population. Conclusions Approximately 7–10% of commercially insured adult patients in the US with RA had moderate or severe renal impairment. Assessment of renal function is an important consideration for safe treatment.