Translation, cross-cultural adaptation and psychometric validation of the Thai version of the STarT Back Screening Tool in patients with non-specific low back pain

BACKGROUND: Low back pain (LBP) is a top musculoskeletal problem and a substantial cause of socioeconomic burden internationally. The STarT Back Screening Tool (SBST) is a useful screening tool to manage patients with LBP but it is unavailable in Thai. Therefore, the aims of this study were to translate and cross-culturally adapt the SBST into a Thai version (SBST-TH) and validate its psychometric properties (e.g., factor analysis, internal consistency, test-retest reliability, agreement, convergent validity and discriminative validity). METHODS: Translation and cross-cultural adaptation of the SBST into Thai version were conducted according to standard guidelines. A total of 200 participants with non-specific LBP were invited to complete the SBST, visual analogue scale for pain intensity, Roland-Morris disability questionnaire (RMDQ), fear-avoidance beliefs questionnaire, pain catastrophising scale, hospital anxiety and depression scale and the EuroQol five-dimensional questionnaire. Thirty participants completed the SBST-TH twice with an interval of 48 h to evaluate test-retest reliability. RESULTS: Factor analysis demonstrated two (physical and psychological) components for the SBST-TH (39.38% of the total variance). The Cronbach’s alpha (0.86 for total score and 0.76 for psychosocial subscore) represent satisfactory internal consistency. The acceptability of intraclass correlation coefficient was found in the total (0.73) and subscore (0.79). The areas under the curve (AUC) for the total score ranged 0.67–0.85 and 0.66–0.75 for subscore. The excellent discriminative validity was observed (AUC = 0.85, 95% confidence interval = 0.72, 0.97) between the total score of the SBST-TH and disability (RMDQ). Spearman’s correlation coefficients represented moderate to strong correlation (0.32–0.56) between the SBST-TH and all questionnaires. The findings suggest a good relationship between the SBST-TH and disability and quality of life. Owing to the results from the convergent and discriminative validity, construct validity of the SBST-TH can be supported. The minimal detectable changes of the total score and subscore were 2.04 and 1.60, respectively. Significant floor and ceiling effects were not found in the SBST-TH. CONCLUSION: The SBST-TH was successfully translated and adapted. It is a valid and reliable tool to classify Thai patients with non-specific LBP into low, moderate and high risks for chronicity. TRIAL REGISTRATION: TCTR20191009005#.