Diabetes-Related Complications and Costs in Medicare Beneficiaries with Comorbid Rheumatoid Arthritis and Diabetes Treated with Abatacept Versus Other Targeted DMARDs

Introduction Targeted DMARD (tDMARD) use in patients with rheumatoid arthritis (RA) and type 2 diabetes mellitus (T2DM) may increase whole-body insulin sensitivity. Evidence comparing the T2DM-related clinical and economic impact of abatacept versus other tDMARDs is limited. This study compared differences in T2DM-related healthcare resource utilization (HCRU) and costs in patients with RA and T2DM. Methods This retrospective study used 100% Medicare Fee-for-Service claims (parts A/B/D) to identify patients ≥ 65 age, diagnosed with RA and T2DM, and were either TNFi-experienced (switched from a TNFi to another tDMARD) or tDMARD-naïve, initiating their first tDMARD (abatacept, TNFi, or non-TNFi) between 2010 and 2017. Abatacept users were propensity-score (PS) matched to TNFi and other non-TNFi users separately on baseline demographics, comorbidities, medications, T2DM-related HCRU, and costs. Post-index follow-up: until discontinuation of index treatment, disenrollment, death, or end of study period, whichever occurred first. T2DM-related complications and HCRU were assessed. Costs were normalized to per-patient-per-month (PPPM) and inflated to 2019 US$. Results The TNFi-experienced group included 2169 abatacept/TNFi and 2118 abatacept/other non-TNFi PS-matched pairs; the tDMARD-naïve group included 2667 abatacept/TNFi and 2247 abatacept/other non-TNFi PS-matched pairs. For TNFi-experienced patients, T2DM-related complication rates for inpatient settings PPPM trended lower for abatacept than TNFi (21 vs. 24, p = 0.046) and other non-TNFi groups (21 vs. 26; p < 0.0001). T2DM-related total costs PPPM for TNFi-experienced patients demonstrated lower trends for abatacept than TNFi ($489 vs. $594, p = 0.016) and other non-TNFi users ($493 vs. $606, p = 0.012). Conclusions Medicare beneficiaries with RA and T2DM who switch to/initiate abatacept as their first tDMARD have directionally lower rates and costs of T2DM-related complications compared with patients switching to/initiating other tDMARDs. Abatacept treatment may help reduce clinical and economic burdens associated with T2DM in patients with RA.