Cost of care for patients with rheumatoid arthritis receiving TNF-antagonist therapy using claims data.

OBJECTIVE: To compare the cost of care for rheumatoid arthritis (RA) patients treated with adalimumab, infliximab, and etanercept.

RESEARCH DESIGN AND METHODS: RA patients were identified from a privately insured database. Three mutually exclusive treatment cohorts were formed based on the date of first tumor necrosis factor (TNF) antagonist treatment (index date) after January 1, 2003. Baseline characteristics were assessed in the 3-month pretreatment period. Healthcare (i.e., medical service and prescription medications) utilization and cost were assessed for the following 12 months. RA-related medical cost included the total cost for medical service associated with RA diagnosis. RA-related healthcare cost included RA-related medical and drug cost. Uneven distribution of baseline characteristics were adjusted with the propensity score method. Cost was compared between treatment cohorts.

RESULTS: Twelve-month TNF-antagonist therapy cost ($12 853 vs. 17 299, p = 0.002), total RA-related drug cost ($13 794 vs. 17 647, p = 0.006), total RA-related medical cost ($971 vs. 2920, p < 0.001), total RA-related healthcare cost ($14 764 vs. 20 566, p = 0.002), and total drug cost ($16 210 vs. 19 769, p = 0.028) were significantly less for adalimumab (n = 217) than infliximab (n = 234). Twelve-month healthcare cost for adalimumab was comparable to etanercept (n = 546).

CONCLUSIONS: Annual healthcare cost for adalimumab patients was significantly less than for infliximab patients and was comparable to etanercept patients. This analysis is subject to the usual limitation of claims data analyses in that few clinical details are available and causal inference conclusions are limited.