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.