Dose adjustment over time of etanercept and infliximab in patients with rheumatoid arthritis.

Dose escalation of biologics in patients with rheumatoid arthritis may affect the cost of care. Longitudinal claims data from a large U.S. health plan were analyzed retrospectively. A total of 4,426 health plan members had a medication claim for either etanercept (N = 690; mean age, 48.4 yr; 72% female) or infliximab (N = 424; mean age, 54.3 yr; 73% female) during the selection period. The study revealed that the mean dosage in patients receiving infliximab for rheumatoid arthritis symptoms increased by 29% from first to last dose. The mean weekly dosage for etanercept remained stable. Etanercept was associated with a significantly lower hazard of dose increase relative to infliximab. The estimated annual costs of infliximab and its administration varied by 31%, whereas the estimated costs of etanercept remained stable over time. This increased dose of infliximab may translate into increased costs for a payer over time.