How does the Short Form 36 Health Questionnaire (SF-36) in Rheumatoid Arthritis (RA) Relate to RA Outcome Measures and SF-36 Population Values? A Cross-Sectional Study

Abstract:

The aim of the study was to show that the SF-36 is a practical tool for use on outpatients with RA, to examine the relationship between the SF-36 and indices of outcome in RA, and to compare the results with population norms and other disease states. Eighty-six consecutive RA patients attending the Haywood Hospital in Stoke-on-Trent and starting or changing second-line therapy were enrolled. Disease outcome was assessed using the American College of Rheumatology core set and all subjects completed the SF-36 health questionnaire. The cohort had moderately active disease (median ESR 46) and appreciable disability (median HAQ 1.875). Impairment of health status was moderate to marked by the SF-36, with significant differences from population norms and chronic disease states such as low back pain. Good correlations were observed between HAQ and physical function (r>0.75, p<10^–6) and HAQ and social function (r>0.61, p<10^–6). In contrast, SF-36 scales for physical and emotional role showed no association with activity measures. We concluded that, SF-36 is a practical tool for use in patients with RA. HAQ is associated with its physical and social function scales. Other SF-36 scales, such as physical and emotional role, are not associated with activity core set measures; this suggests different information is involved. RA has a considerable impact on health status compared to other diseases.