RESUMO
PURPOSE: To explore the evidence of the internal structure validity of the Roland-Morris Disability Questionnaire in older adults with low back pain. METHODS: This was a cross-sectional study of psychometric testing involving 528 older adults with low back pain. Internal structure validity was explored by exploratory factor analysis and semi-confirmatory factor analysis. Reliability was verified using Kuder-Richardson Formula 20, Cronbach's alpha, and McDonald's omega. Replicability was observed by the generalized H index. RESULTS: Roland-Morris Disability Questionnaire displayed two factors that assess "functional capacity" and "mobility". Eight items were excluded for presenting cross-loading (2 and 10), inadequate loading factors and communalities (18, 24, 13, and 12), or did not relate to the latent construct (15 and 22). Semi-confirmatory factor analysis indicated that the questionnaire had a good fitness model [X2 = 153.698 (p = 0.00001); RMSEA = 0.037; RMSR = 0.06; WRMR = 0.04; NNFI = 0.987; GFI = 0.979; AGFI = 0.971]. Reliability was acceptable (KR-20 = 0.79; Cronbach's alpha = 0.86; McDonald's Omega = 0.85), but replicability was poor in both factors (G-H factor 1 = 0.816-0.655; G-H factor 2 = 0.889-0.775). CONCLUSIONS: The most appropriate version of the Roland-Morris Disability Questionnaire to apply to older adults with low back pain has 16 items and assesses functional capacity and mobility. IMPLICATIONS FOR REHABILITATIONThe RMDQ-16 is the most appropriate version of the RMDQ to use in older adults with LBP;The RMDQ-16 is bidimensional and assesses "functional capacity" and "mobility";The poor replicability of the RMDQ-16 indicates that it will probably not be stable across studies, but it can be useful in a clinical setting.
