The reliability and validity of the Turkish version of the graded chronic pain scale in patients with chronic low back pain

Purpose To translate and cross-culturally adapt the Turkish version of the Graded Chronic Pain Scale-Revised (GCPS-R) and to evaluate its reliability and validity. Methods The prospective and cross-sectional study was performed with 102 low back pain patients (67 women, 35 men). Patients were asked to complete the GCPS-R twice, one week apart. Visual Analog Scale (VAS), Roland Morris Disability Questionnaire (RMDQ), Short Form-36 (SF-36), Fear Avoidance Beliefs Questionnaire (FABQ) were filled only in the first evaluation. Test-retest reliability was analyzed with intraclass correlation coefficient (ICC). Internal consistency was measured using Cronbach's alpha. The minimal detectable change (MDC95) was calculated based on the standard error of measurement (SEM95). The construct validity was analyzed using the Pearson correlation coefficient. Exploratory factor analysis was calculated to explore the factor structure of GCPS-R. Results The mean age of the patients was 45.2 +/- 13.1 years. The internal consistency was acceptable, and test-retest reliability was excellent (alpha = 0.933, ICC = 0.972). SEM95 and MDC95 for the total score were 2.07 and 5.73, respectively. VAS measured for both rest and activity were strongly correlated with GCPS-R (r > 0.50). The correlation between the total score of GCPS-R and RMDQ was excellent (r = 0.677, p < 0.001). SF-36's; physical function, role physical, bodily pain and social function subscores were strongly correlated with GCPS-R (r > 0.50). There was moderate correlation between GCPS-R and the physical activity subscore of the FABQ (r = 0.494, p < 0.001). GCPS-R had a single factor structure as expected. Conclusion The Turkish version of GCPS-R is a valid and reliable questionnaire in patients with chronic low back pain. Level of Evidence II (Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding).