Biologic Cost per Effectively Treated Rheumatoid Arthritis Patient in a Large Managed Care Population: A Retrospective Cohort Study

Abstract

**Background:** Until recently, the lack of clinical outcomes information for rheumatoid arthritis (RA) in administrative claims databases limited their use in comparative effectiveness research. A validated claims-based algorithm has been developed to estimate the effectiveness of biologics for RA, allowing for estimation of cost and effectiveness in the same database. **Objectives:** To implement a validated claims-based effectiveness algorithm in a US managed care claims database to compute the 1-year biologic cost per effectively treated patient among first-line biologics approved for moderate-to-severe RA (abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, and infliximab). **Methods:** This retrospective cohort study used administrative claims data for individuals in the HealthCore Integrated Research Database (HIRDSM). The first claim for a first-line biologic between July 1, 2009, and January 31, 2013, after 6 months of continuous enrollment, was defined as the index event and date. Patients were aged 18-63 years on the index date and had at least one claim for RA in the 6-month pre- index period. Biologic costs included plan and patient paid amounts on claims for the biologic drug and administration. The algorithm defined effectiveness during the 12-month post-index period as achieving all six of the following: high adherence (medication possession ratio ≥80% or infusions consistent with the product label); no increase in biologic dose or decrease in dosing interval; no new biologic; no new nonbiologic disease-modifying antirheumatic drug; no new or increased oral glucocorticoid use; and ≤1 glucocorticoid injection. Cost per effectively treated patient was calculated as the total biologic cost (drug and administration) divided by the number of patients categorized by the algorithm as effectively treated. **Results:** The cohort comprised 4844 patients (mean age 48.6 years, 76.4% female). Average first-year biologic cost ranged from $14 795 (golimumab) to $19 520 (abatacept). Average first-year biologic cost per effectively treated patient was significantly lower for etanercept ($50 217) than for golimumab ($56 427, p<0.001) adalimumab ($56 879, p<0.001), abatacept ($68 062, p<0.001), certolizumab pegol ($76 427, p<0.001), and infliximab ($95 126, p<0.001). **Conclusions:** In this application of a validated claims-based algorithm to a large managed care population, etanercept had the lowest 1-year biologic cost per effectively treated patient among first-line biologics.