Objective: To compare the impact of leflunomide on resource utilization and costs relative to that of etanercept and infliximab among patients with rheumatoid arthritis (RA) in a managed care setting.
Methods: Data were obtained from the PharMetrics Integrated Outcomes Database for all patients newly starting 1 of the 3 medications of interest in 1999 or 2000. Claims were compiled for 180 days prior to the first prescription for study therapy and for a minimum of 90 days thereafter. Measures of interest during follow-up included the incidence of significant interventions (eg, joint injection, synovectomy), 1-year utilization of study therapy, other RA-related medications, inpatient and outpatient services, and total costs of RA-related care. Data were adjusted for variable follow-up using survival techniques. Multivariate analyses were conducted on total costs, controlling for between-group differences in demographic, clinical, and pretreatment characteristics.
Results: A total of 4069 patients were included in the study cohort (n = 2217, 1547, and 305 for leflunomide, etanercept, and infliximab, respectively). Three quarters of the cohort were female; etanercept patients were somewhat younger than leflunomide or infliximab recipients. Severity of illness (as measured by the Charlson index) was highest among infliximab patients. The incidence of significant interventions was high in all patients, but did not differ by treatment group. Use of nonsteroidal anti-inflammatory drugs (8.1 versus 8.9 claims) and narcotic analgesics (7.8 versus 8.5) was substantially lower for leflunomide than for etanercept. Costs of RA-related care were 42% to 53% lower among leflunomide patients for biologic medications ($9618 versus $16,534 and $20,263 for etanercept and infliximab, respectively), primarily as a result of lower medication costs. Findings persisted in multivariate analyses of cost.
Conclusions: Leflunomide is associated with reduced costs of medications and other healthcare services relative to biologic medications among managed care patients with RA.