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 McGill Pain Questionnaire Version-2 (SF-MPQ-2) is a multidimensional outcome measure designed to capture, evaluate and discriminate pain from neuropathic and non-neuropathic sources. A recent systematic review found insufficient psychometric data with respect to musculoskeletal (MSK) health conditions. This study aimed to describe the reproducibility (test–retest 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 MSK sources completed the SF-MPQ-2: at baseline (n = 195), and a subset did so again after 3–7 days (n = 48), if their response to the Global Rating of Change (GROC) scale remained unchanged. Cronbach alpha (α) and intraclass correlation coefficient (ICC(2,1)), and their related 95% CI were calculated. Standard error of measurement (SEM), group and individual minimal detectable change (MDC90), and Bland–Altman (BA) plots were used to assess agreement. RESULTS: Cronbach 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 scale (0.95) and continuous subscale (0.92) scores; 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 = 0.13–0.19). While the best agreement coefficients were seen on the total scale (SEM = 0.5; MDC(90individual) = 1.2 and MDC(90group) = 0.3), they were acceptable for the SF-MPQ-2 subscales (SEM: range 0.7–1; MDC(90individual): range 1.7–2.3; MDC(90group): range 0.4–0.5). CONCLUSION: Good reproducibility supports the SF-MPQ-2 domains for augmented or independent use in MSK-related shoulder pain assessment, with the total scale displaying the best reproducibility coefficients. Additional research on the validity and responsiveness of the SF-MPQ-2 is still required in this population.