Reproducibility: Reliability and Agreement Parameters of the Revised Short McGill Pain Questionnaire Version-2 for use in Patients with Musculoskeletal Shoulder Pain

Background: The Revised Short-Form McGill Pain Questionnaire Version-2 (SF-MPQ-2) is a multidimensional outcome measure designed to evaluate neuropathic and nonneuropathic pain. A recent systematic review found insufficient psychometric data with respect to musculoskeletal health conditions. Aims: The aim of this study was to describe the reproducibility (reliability and agreement) and internal consistency of the SF-MPQ-2 for use among patients with musculoskeletal shoulder pain. Methods: Eligible patients with shoulder pain from musculoskeletal (MSK) sources completed the SF-MPQ-2 at baseline (n = 195), and a subset did so again after 3 to 7 days (n = 48) if their response to the global rating of change scale remained unchanged. Cronbach's alpha (α) and intraclass correlation coefficient (ICC[2,1]) were calculated. Standard error of measurement (SEM), group and individual minimal detectable change (MDC90), and Bland-Altman plots were used to assess agreement. Results: Cronbach's α ranged from 0.83 to 0.95, suggesting very satisfactory internal consistency across the SF-MPQ-2 domains. Excellent ICC(2,1) scores were found in support of the total (0.95) and continuous (0.92) subscales; the remaining subscales displayed good ICC(2,1) scores (0.78-0.88). Bland-Altman analysis revealed no systematic bias between the test and retest scores (mean difference = 0.13 to 0.19). Though the best agreement coefficients were seen on the total scale (SEM = 0.5; MDC90 = 1.2, MDC90_group = 0.3), they were acceptable for the SF-MPQ-2 subscales (SEM: range, 0.7-1; MDC90: range, 1.7-2.3; MDC90_group: range, 0.4-0.5). Conclusions: The SF-MPQ-2 provides good to excellent test-retest reliability for multidimensional pain assessment among patients with musculoskeletal shoulder pain conditions.