Reliability and aspects of validity of the Swedish version of self-efficacy for exercise scale for patients with chronic pain

BACKGROUND: Active, specific, and professionally led physical exercise is an effective treatment for chronic pain, and self-efficacy is correlated to positive treatment outcomes. At present, there is limited knowledge of self-efficacy for exercise in patients with chronic pain. PURPOSE: To evaluate the reliability and aspects of validity of the Swedish version of the Self-Efficacy for Exercise Scale (SEE-SV) in patients with chronic pain. METHODS: Patients with chronic pain were recruited from a specialist clinic. The Swedish version of the SEE was used. Reliability was evaluated through internal consistency, test-retest, and measurement error (standard error of measurement, SEM and smallest detectable change, SDC). Construct validity was calculated using the correlation between the SEE-SV and other well-established evaluation instruments. Content validity was evaluated both from a patient and a health-care professional perspective. RESULTS: In total, 44 patients, 31 women and 13 men (mean age 40 years), participated in the study. The SEE-SV had good test-retest reliability (intra-class correlation coefficient (ICC) = 0.95) and internal consistency (Cronbach's alpha = 0.97). Regarding measurement error, SEM was 4.9 and SDC 13.5. Moderate correlation was seen between SEE-SV and a pain-specific self-efficacy questionnaire (rs = 0.52). The majority of patients and health-care professionals considered the SEE-SV to be relevant and easy to understand. CONCLUSION: The SEE-SV showed a good internal consistency, item-to-total correlation, and test-retest reliability (ICC). A relatively high SDC indicates an individual variability of the test results. The content validity was satisfactory. Regarding the construct validity, further studies are needed.