To evaluate the construct validity of the SF-6D among a sample of Brazilian patients with rheumatoid arthritis.
This was a validation and cross-cultural adaptation study. Preference evaluation instruments were applied: SF-6D, EQ-5D, VAS, TTO and SG. Clinical and sociodemographic parameters were obtained. Descriptive statistics, correlation coefficients and ANOVA were used to analyze the results.
200 patients were evaluated, among whom the non-completion rates were 0.5% for VAS, 1.5% for TTO and 6.5% for SG. The preferences derived from the SF-6D presented the strongest correlations with EQ-5D and HAQ, followed by VAS, TTO and SG, in decreasing order. The correlations with clinical and sociodemographic parameters were, in most cases, small. The preferences obtained with the SF-6D could discriminate patients with different HAQ levels.
The SF-6D is a valid method for measuring preferences in patients with rheumatoid arthritis in a Brazilian context.