A Roland Morris Disability Questionnaire Target Value to Distinguish between Functional and Dysfunctional States in People with Low Back Pain

PURPOSE To estimate a threshold Roland Morris Disability Questionnaire (RMQ) value that could be used to classify patients with low back pain (LBP) as functional or dysfunctional. METHODS In this secondary analysis of data from a study that estimated clinically important RMQ change scores, participants were adults with LBP attending one of three physical therapy clinics. Diagnostic test methodology and a reference standard of goals met were applied to estimate a threshold RMQ value that best distinguished between participants with a functional status and those whose status was dysfunctional. RESULTS Of 143 participants, 104 (73%) met their goals. An RMQ threshold value of 4/24 best distinguished between those who met their goals and those who did not. Sensitivity and specificity for a threshold score of 4 were 94% (95% CI, 88-98) and 69% (95% CI, 52-83), respectively. CONCLUSIONS A threshold value of 4 RMQ points provided a reasonably accurate classification of patients. Further research is necessary to cross-validate this estimate and to examine the stability of the estimated value in people with diverse functional demands.