To describe the dosing of etanercept and infliximab for the treatment of rheumatoid arthritis (RA).
Adult patients with a diagnosis of RA who were treated with either etanercept or infliximab between 1999 and 2002 were selected from 16 rheumatology practices in the western and southeastern United States. Patients with a terminal illness or those receiving a tumor necrosis factor (TNF)-alpha inhibitor for an indication other than RA were excluded. Data were collected through a review of the patient medical records. Data collected on each patient included demographics, concurrent disease-modifying antirheumatic drug therapy, TNF-alpha inhibitor dose, frequency, duration of TNF-alpha inhibitor therapy, and discontinuation of TNF-alpha inhibitor therapy.
A total of 244 patients were included in the evaluation (etanercept only [n=128; 52%], infliximab only [n=89; 36%], both [n=27; 11%]). The mean age of these patients was 55.1+/-13.3 years, 54.9+/-13.5 years, and 52.8+/-14.0 years, respectively; the mean duration of RA was 13.3 +/- 8.8 years, 13.4+/-8.0 years, and 14.0 +/- 9.9 years, respectively. Female patients constituted 70% of the sample. Health maintenance organization insurance was the most common form of medical insurance (45.8%), followed by Medicare (22.3%). The mean duration of follow-up for etanercept and infliximab treatment was 29.3+/-14.1 months and 14.8+/-6.9 months, respectively. Among patients who were still receiving therapy at the time of review, the mean initial and last etanercept doses were 25.0 mg versus 25.8 mg (P=0.16); the mean initial and last infliximab doses were 3.38 mg/kg versus 4.51 mg/kg (P<0.001).
The dosing of etanercept and infliximab therapy was consistent with the approved labeling of both medications.