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.

Background: In 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.

Methods: In 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.

Results: For 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.

Conclusions: In 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 Registration: ClinicalTrials.gov, NCT00848354.