Self-reports and clinician-measured physical function among patients with low back pain: A comparison

Objective: To determine the relationships among self-reported activity limitation and clinician-measured functional performance tests. Design: Case series survey. Setting: A referral-based orthopedic spine clinic in Houston, TX. Patients: Eighty-three patients (48 women, 35 men) with low back pain (LBP). Interventions: The Roland-Morris Disability Questionnaire (RMDQ) and a physical performance test (PPT) battery. Main Outcome Measures: Self-reported activity limitation (eg, walking, bending, getting out of chair, putting on sock, doing heavy jobs) was assessed by the RMDQ. Clinician-measured functional performance was assessed with the PPT, a battery comprised 6 tests: Lumbar flexion range of motion, a 50-foot walk at fastest speed, a 5-minute walk, 5 repetitions of sit-to-stand, 10 repetitions of trunk flexion, and loaded reach task (patients reached forward while holding a weight weighing 5% of their body weight). Results: Pearson's product-moment correlations between total RMDQ score and each of the performance tests ranged from .29 to .41. Point biserial correlations between individual RMDQ items and their corresponding performance tests were slightly lower, ranging from .20 to .33. Conclusion: There were moderate correlations between self-reported activity limitation and corresponding clinician-measured performance tests. The unique perspective each method provides appears to be useful for a comprehensive understanding of physical function in patients with LBP.