Minimum clinically important changes in disability in a prospective case series with chronic thoracic and lumbar spinal pain

Abstract

Objective: Values for the minimum clinically important change (MCIC) are not available for the PatientSpecific Functional Scale (PSFS) for the thoracic spine. MCIC values for the Roland–Morris Disability Questionnaire (RMDQ) are available but vary depending on the intervention and the method of calculation. This study provides new estimates of the MCIC of these two disability measures based on global impression of change (GIC) responses and correlates changes in the disability measures with GIC responses. Methods: The study comprised a consecutive case series of 143 participants with chronic spinal pain recruited over 2 years from an urban private practice in Canada. They were treated with dextrose prolotherapy injections and followed for a year. We calculated the MCICs by comparing mean change scores with GIC ratings using the within-patient method and the sensitivity–specificity approach. Results: The MCICs calculated by the within-patient method and the sensitivity–specificity approach for the PSFS in the thoracic region were 2.9 (95% confidence interval (CI) 2.2, 3.5) and 2, respectively. MCICs for the RMDQ in the lumbar region were 5.0 (95% CI 3.4, 6.7), and 5, respectively. Correlations between the GIC for function and the PSFS were 0.57 (P < 0.0001) and between the GIC for function and the RMDQ were 0.46 (P < 0.0001). Discussion: The MCICs for the PSFS for the thoracic spine were similar to previous estimates for neck pain with radiculopathy. The MCICs for the RMDQ were similar to previous estimates. These values may be of use to researchers in designing and analysing clinical trials and to clinicians in estimating the likelihood of patients’ responses to treatment of back pain.