BACKGROUND: Administrative claims contain detailed medication, diagnosis, and procedure data, but the lack of clinical outcomes for rheumatoid arthritis (RA) historically has limited their use in comparative effectiveness research. A claims-based algorithm was developed and validated to estimate effectiveness for RA from data for adherence, dosing, and treatment modifications. OBJECTIVE: To implement the claims-based algorithm in a U.S. managed care database to estimate biologic cost per effectively treated patient. METHODS: The cohort included patients with RA aged 18-63 years in the Optum Research Database who initiated biologic treatment between January 2007 and December 2010 and were continuously enrolled 6 months before through 12 months after the first claim for the biologic (the index date). Patients were categorized as effectively treated by the claimsbased algorithm if they met all of the following 6 criteria in the 12-month post-index period: (1) a medication possession ratio ≥ 80% for subcutaneous biologics, or at least as many infusions as specified in U.S. labeling for intravenous biologics; (2) no increase in biologic dose; (3) no switch in biologics; (4) no new nonbiologic disease-modifying antirheumatic drug; (5) no new or increased oral glucocorticoid treatment; and (6) no more than 1 glucocorticoid injection. Drug costs (all biologics) and administration costs (intravenous biologics) were obtained from allowed amounts on claims. Biologic cost per effectively treated patient was defined as total 1-year biologic cost divided by the number of patients categorized by the algorithm as effectively treated with that index biologic. Sensitivity analysis was conducted to examine the total health care costs per effectively treated patient during the first year of biologic therapy. RESULTS: A total of 5,474 individuals were included in the analysis. The index biologic was categorized as effective by the algorithm for 28.9% of patients overall, including 30.6% for subcutaneous biologics and 22.1% for intravenous biologics. The index biologic was categorized as effective in the first year for 32.7% of etanercept (794/2,425), 32.3% of golimumab (40/124), 30.2% of abatacept (89/295), 27.7% of adalimumab (514/1,857), and 19.0% of infliximab (147/773) patients. Mean 1-year biologic cost per effectively treated patient, as defined in the algorithm, was lowest for etanercept ($43,935), followed by golimumab ($49,589), adalimumab ($52,752), abatacept ($62,300), and infliximab ($101,402). The rank order in the sensitivity analysis was the same, except for golimumab and etanercept. CONCLUSIONS: Using a claims-based algorithm in a large commercial claims database, etanercept was the most effective and had the lowest biologic cost per effectively treated patient with RA.