Treatment persistence with adalimumab, etanercept, or infliximab in combination with methotrexate and the effects on health care costs in patients with rheumatoid arthritis

Background: Anti-tumor necrosis factor (TNF) biologic agents are effective in treating rheumatoid arthritis (RA). Information on patient persistence with biologic anti-TNF therapies is limited, and the effects of persistence on the costs of therapy are unknown.Objectives: The aims of this study were to compare treatment persistence with adalimumab, etanercept, or infliximab in combination withmethotrexate (MTX) and evaluate the effects of persistence on overall health care costs.Methods: This retrospective study used data from the PharMetrics managed care administrative claims database. Data from patients with RA who received combination treatment with an anti-TNF agent plus MTX and had ≥24 months of continuous plan eligibility were collected. The 3 anti-TNF cohorts were adalimumab + MTX (adalimumab group), etanercept + MTX (etanercept group), and infliximab + MTX (infliximab group). Treatment persistence was defined as the number of days between the first and last anti-TNF treatment and was reported as a percentage of the 1-year period after treatment initiation. Costs were compared between patients with treatment persistence rates ≥80% or <80%. Demographics, comorbidities, disease severity, and RA-related costs were assessed using descriptive statistics. Univariate and multivariate analyses were applied to identify differences in mean persistence between the 3 cohorts.Results: Data from 1242 patients were included (77.7% female; mean age, 50.0 years). The mean persistence rate in the overall population was 74.6%, and the mean treatment time was 272.3 days. The infliximab group had a higher persistence rate compared with the etanercept and adalimumab groups (78.0% vs 72.8% and 70.8%, respectively; P < 0.005). In all patients combined, those with treatment persistence ≥80% had higher mean total health care costs compared with those with treatment persistence <80% ($19,271.52 vs $15,598.46; P < 0.001), largely due to higher pharmacy costs. However, nonpharmacy costs were lower in the ≥80% persistence cohort ($3091 vs $4601; P = 0.015).Conclusions: In this population of patients with RA, overall treatment persistence was high, with patients treated with infliximab + MTX having significantly higher persistence compared with those treated with adalimumab + MTX or etanercept + MTX. While pharmacy costs were higher in patients with ≥80% persistence, nonpharmacy costs were lower.