Refining a Claims-based Algorithm to Estimate Biologic Medication Effectiveness and Cost per Effectively Treated Patient with Rheumatoid Arthritis.

Background: Claims data generally lack information on clinical outcomes. However, a validated claims-based algorithm for estimating the effectiveness of biologic agents in treating rheumatoid arthritis (RA) was recently developed and applied to various databases.

Objectives: The objectives of the study were to implement a claims-based algorithm in a large nationwide database to estimate medication effectiveness and cost for patients with RA using biologic disease-modifying antirheumatic drugs (DMARDs) and to assess the effect of eliminating one criterion from the algorithm on results.

Methods: The DMARD groups included patients initiated on etanercept, adalimumab, abatacept, or infliximab. Patients were categorized as effectively treated if they met these six criteria: a medication possession ratio of 80% or greater; no escalation in biologic dose; no switch in biologics; no new nonbiologic DMARD; no new or increased oral glucocorticoid treatment; and no more than one glucocorticoid injection. In a follow-up analysis, the dose-escalation criterion was removed because an increase in dose for infliximab may be appropriate. Average costs for RA-related medications were calculated for each DMARD patient group and divided by the number of patients who met all six effectiveness criteria.

Results: A total of 1196 individuals were included in the analysis. Using the algorithm, the index biologic was categorized as effective for 25.4% of patients overall: 30.3% (102/337) of etanercept, 27.6% (104/377) of adalimumab, 32.7% (37/113) of abatacept, and 16.5% (61/369) of infliximab patients. Total costs for RA medication costs per effectively treated patient ranged from more than $80,000 for infliximab to ~$43,000-$46,000 for the other three groups. Removing the no dose-escalation criterion drastically reduced the cost per effectively treated patient in the infliximab group (to ~$42,000).

Conclusions: Using the original six-criteria claims-based algorithm in a large claims database, infliximab was the least-effective biologic agent and had the highest medication cost per effectively treated patient. However, when a follow-up analysis removed the dose-escalation exclusion criterion, the four groups had similar effectiveness and medication costs per effectively treated patient with RA.