Retrospective study of the costs of care during the first year of therapy with etanercept or infliximab among patients aged ≥65 years with rheumatoid arthritis

Abstract

The aim of this work was to retrospectively examine the costs of therapy with etanercept and infliximab, among patients aged > or = 65 years with rheumatoid arthritis (RA), from a health-care system perspective. Data from 2 large, automated US health-care claims databases (Constella COMPASS and Ingenix LabRx) were pooled for the analyses. Each database is comprised of paid facility, professional service, and retail (ie, outpatient) pharmacy claims from participating health plans. Using the 2 databases, all RA patients aged > =65 years were identified who began therapy with etanercept or infliximab between July 1, 1999 (Constella COMPASS), or January 1, 2001 (Ingenix LabRx), and December 31, 2002. Costs of RA-related care (including study drugs, selected medications, and outpatient encounters for RA) and non-RA-related care (all other medications and services) for patients in the 2 treatment groups were assessed, in US dollars, over a 1-year period after therapy initiation. A total of 280 RA patients aged > or = 65 years initiated therapy with etanercept (n = 99) or infliximab (n = 181) and met all other selection criteria. Etanercept patients were younger than infliximab patients (mean [SD] age, 70.5 [4.6] vs 71.8 [4.6] years; P = 0.04), were less likely to be enrolled in a managed care organization (76.7% vs 87.8%; P < 0.01), and had fewer pretreatment rheumatologist visits (mean [SD], 1.3 [2.3] vs 2.2 [3.8]; P = 0.04). Other characteristics, including pretreatment levels of other types of health-care utilization, were generally similar. Mean (95% CI) total cost of RA-related care was lower for etanercept patients in both databases (US 12,159 dollars [US 10,795 dollars-US 13,380 dollars] for etanercept vs US 22,347 dollars [US 20,808 dollars-US 23,912 dollars] for infliximab in one, and US 14,297 [US 12,238 dollars-US 16,326 dollars] for etanercept vs US 22,154 dollars [US 19,688 dollars-US 24,703 dollars] for infliximab in the other), primarily due to lower costs of anti-tumor necrosis factor therapy (US 10,015 dollars [US 8754 dollars-US 11,224 dollars] for etanercept vs US 18,611 dollars [US 17,169 dollars-US 20,023 dollars] for infliximab in one database; US 11,917 dollars [US 10,128 dollars-US 13,480 dollars] for etanercept vs US 16,759 dollars [US 14,551 dollars-US 19,062 dollars] for infliximab in the other). Mean (95% CI) costs of non-RA-related care were similar among etanercept and infliximab patients in both databases (US 13,100 dollars [US 8956 dollars-US 18,377 dollars] for etanercept vs US 11,789 dollars [US 8326 dollars-US 16,001 dollars] for infliximab in one, and US 16,665 dollars [US 10,329 dollars-US 25,690 dollars] for etanercept vs US 13,959 dollars [US 10,216 dollars-US 18,168 dollars] for infliximab in the other). These results suggest that costs of RA-related care during the first year of therapy may be lower among RA patients aged > or =65 years receiving etanercept versus infliximab, a difference attributable primarily to lower costs of drug acquisition.