Clinical Improvements as Predictors of Improvements in Patient-Reported Outcomes: Post Hoc Analysis of a Randomized, Open-Label Study of Etanercept in Latin American Patients with Rheumatoid Arthritis.

Abstract

BackgroundIn rheumatoid arthritis (RA), little is known about clinical responses to treatment as predictors of patient-reported outcome (PRO) changes. In this post hoc analysis, we examined the relationship between clinical outcomes at week 12 and PRO changes at week 24 in patients with RA.MethodsIn an open-label study, Latin American patients with moderate-to-severe RA and an inadequate response to methotrexate (MTX) were randomized to receive etanercept 50 mg/week plus MTX (ETN+MTX; n=281) or an additional conventional disease-modifying anti-rheumatic drug (DMARD) plus MTX (DMARD+MTX; n=142) for 24 weeks. The PROs included Health Assessment Questionnaire Disability Index (HAQ-DI), 36-item Short Form (SF-36), Physician and Patient Global Assessment scores (PGA, PtGA), Physician and Patient Satisfaction, and an activity impairment assessment. PRO changes at week 24 were calculated by week-12 improvements using the American College of Rheumatology criteria (ACR <20, ≥20 to <50, ≥50 to <70, and ≥70) and the 28-joint Disease Activity Scores (DAS28 ≥3.2, ≥2.6 to <3.2, and <2.6). Observed-cases data were analyzed using an ANCOVA model with linear contrast, adjusted for baseline PRO and ACR/DAS28 values.ResultsFor both ETN+MTX- and DMARD+MTX-treated patients, there was a significant linear trend between week-12 changes in ACR and DAS28 responses and week-24 changes in HAQ-DI (P<0.001 for all), with numerical improvements generally favoring ETN+MTX. Similar relationships were observed for SF-36, PGA, PtGA, Physician Satisfaction, Patient Satisfaction, and activity impairment.ConclusionsIn patients with RA, clinical response after 12 weeks of treatment with ETN+MTX or DMARD+MTX could be a predictor of week-24 response for several PROs.Trial registrationClinicalTrials.gov, NCT00848354.