Concurrent validity of the brazilian version of SRS-22r with Br-SF-36

Background: An important parameter in cross-cultural adaptations, and concurrent validity are the relationships between the performance of an instrument of interest and the performance of a similar instrument with known validity. Objective: To determine the concurrent validity of the Brazilian version of the revised questionnaire of the Scoliosis Research Society (Br-SRS-22r) and the Brazilian version of the Short-Form-36 questionnaire (SF-36). Methods: Fifty-four patients with idiopathic scoliosis were selected. The mean age was 19.9 yrs. (+/- 7.7) and the mean Cobb angle of curvature was 31.6 degrees (+/- 20.5 degrees), ranging from 10 degrees to 92 degrees. The results from each questionnaire were converted into scores and, in the statistical analyses, the relationships between the concurrent domains were analyzed using Spearman's correlation coefficient. Results: The best correlations were found between the function and pain domains: function in the Br-SRS-22r and physical function in the Br-SF-36 (r=0.83); pain in the Br-SRS-22r and pain in the Br-SF-36 (r=0.86). However, the domains of self-image and satisfaction with treatment with the Br-SRS-22r showed moderate and poor correlations with their corresponding domains in the Br-SF-36. There were moderate correlations between the questionnaires, with the best correlations showing greater similarity in the evaluated parameters between the respective instruments. Unlike the function and pain domains, the mental health domains did not have a good correlations, possibly because of difficulties in interpreting of the questions in the Br-SF-36. For the self-image and satisfaction domains, the correlations were moderate and poor because these topics were not specifically covered by the SF-36. Conclusions: The Brazilian version of the SRS-22r demonstrated moderate concurrent validity results in relation to the Br-SF-36, and this version adapted for the Brazilian culture was deemed valid.