Clinical improvement as reflected in measures of function and health- related quality of life following treatment with leflunomide compared with methotrexate in patients with rheumatoid arthritis: Sensitivity and relative efficiency to detect a treatment effect in a twelve-month, placebo-controlled trial

Objective. To examine correlations between clinical improvement as defined by the American College of Rheumatology (ACR) responder analysis and clinical improvement as determined by 4 function and/or health-related quality of life measures, and to estimate the sensitivity and relative efficiency of these measures compared with changes in the tender joint count in patients with rheumatoid arthritis (RA). Methods. A 52-week, multicenter, double-blind controlled trial was conducted to compare treatment with leflunomide (n = 182), methotrexate (n = 180), or placebo (n = 118) in patients with active RA. ACR response rates and improvement in scores on the Health Assessment Questionnaire (HAQ), Problem Elicitation Technique (PET), and medical outcomes survey short form 36 (SF-36) were compared in 438 of the patients. Results. In comparing leflunomide with placebo, the patient global assessment, HAQ disability index, and SF-36 bodily pain scale were most responsive to treatment group differences. The modified HAQ (M-HAQ), PET top 5, SF-36 physical component score, physician global assessment, pain intensity scale, and SF-36 physical functioning scale were more responsive to treatment group differences than was the tender joint count. In comparing methotrexate with placebo, the patient and physician global assessments were most responsive. These 2 measures, as well as the pain intensity scale and the C-reactive protein level, were more responsive to treatment group differences than was the tender joint count, while the SF-36 mental health component score was least responsive. A close correlation between changes in the M-HAQ and HAQ scores indicated that the M-HAQ was similarly responsive to change over time. Improvements in the PET, SF-36 physical component score, bodily pain, and physical functioning scales correlated with the ACR responder status. Conclusion. Both disease-specific and generic measures of function and health-related quality of life detect improvements in RA patients. Using both types of measures for evaluating therapies will identify discernible changes that are important to patients, and will facilitate comparison across different disease states.