Comparison of infection-related hospitalization risk and costs in tumor necrosis factor inhibitor-experienced patients with rheumatoid arthritis (RA) treated with abatacept or other targeted disease-modifying anti-rheumatic drugs (tDMARDs).

Background: Evidence on the cost and risk of infection-related hospitalizations associated with targeted disease-modifying anti-rheumatic drugs (tDMARDs) in patients with RA previously treated with a tumor necrosis factor inhibitor (TNFi) is limited. This study compared the risk and cost of infection-related hospitalizations in commercially insured TNFi-experienced RA patients receiving abatacept, TNFi, or another non-TNFi.
Methods: A retrospective observational study was conducted using 2 large insurance claims databases (1 January 2009-30 June 2017). Adult TNFi-experienced RA patients initiating a subsequent tDMARD (initiation date of tDMARD = index date) with 12 months of continuous enrollment pre-index date, and who had ≥1 inpatient or ≥2 outpatient medical RA claims on 2 different dates were included. Abatacept was compared to TNFis (adalimumab, certolizumab pegol, etanercept, golimumab, and infliximab) and other non-TNFis (tocilizumab, rituximab, and tofacitinib). Cox proportional hazards models estimated the adjusted risk for infection-related hospitalization; costs were calculated on a per-member-per-month (PMPM) and per-patient-per-month (PPPM) basis using generalized linear models.
Results: More patients in the abatacept cohort had an infection-related hospitalization at baseline (4.5%) vs TNFis (2.0%, p < .0001) and other non-TNFis (3.6%, p = .2619). However, during follow-up abatacept patients had fewer infection-related hospitalizations (abatacept: 2.8%, TNFi: 3.7% and other non-TNFis: 5.2%; p < .05). Regression results indicated that compared to patients on abatacept, patients receiving a TNFi [HR: 1.6 (95% CI: 1.1, 2.2)] and other non-TNFis [HR: 1.9 (95% CI: 1.3, 2.8)] had a significantly higher risk of infection-related hospitalization. Abatacept PMPM costs were lowest ($0.25 vs $0.39 and $0.43 for TNFi and other non-TNFi respectively). Mean PPPM (95% CI) cost in the follow-up was lower for abatacept compared to TNFi ($73 vs. $115; p = .042), and other non-TNFi ($73 vs. $125; p = .039).Conclusions: There were significantly lower infection-related hospitalizations and associated costs in TNF-experienced RA patients treated with abatacept than TNFis and other non-TNFis.