Cross-cultural adaptation and psychometric testing of the Arabic version of the Modified Low Back Pain Disability Questionnaire

BACKGROUND: The Modified Low Back Pain Disability Questionnaire (MLBPDQ) is used for evaluating the functional disability in patients with low back pain (LBP). However, the measurement characteristics of the MLBPDQ among Arab patients are unknown. In this study, we aimed to translate and cross-culturally adapt the MLBPDQ into Arabic and evaluate its psychometric properties. METHODS: An Arabic version of the MLBPDQ was developed through forward translation, translation synthesis, and backward translation. Sixty-eight patients (55 males and 13 females) with a mean age 37.01 ± 7.57 years were recruited to assess its psychometric properties. Reliability was evaluated using internal consistency (Cronbach’s α), test retest reliability (utilizing intraclass correlation coefficient [ICC]), standard error of measurement (SEM), minimal detectable change at 95% confidence level (MDC(95%)), and 95% limits of agreement (LOA). The construct validity was investigated by correlating the new translation with four other measures of LBP (using Spearman’s rho). Finally, receiver operating characteristic curve was constructed to compute the sensitivity, using the area under the curve (AUC), and the minimum important change (MIC). An alpha level of 0.05 was set for statistical tests and all the psychometric values were tested against a priori hypotheses. RESULTS: The culturally aligned MLBPDQ showed good internal consistency (Cronbach’s α = 0.85). The ICC, SEM, MDC(95%), and LOA between baseline and two days later were 0.98, 1.60, 4.43, and -4.23 to 7.70, respectively, while the values between baseline and 14 days later were 0.94, 2.77, 7.67, and -6.59 to 13.53, respectively. The scale also demonstrated moderate to excellent correlation (rho = 0.54–0.86) with the other four questionnaires. The AUC value of the Arabic-MLBPDQ was 0.68, and the MIC was 3 points. CONCLUSION: The Arabic version of the MLBPDQ demonstrates adequate psychometric properties and can be used to assess disability level in patients with LBP in Arabic-speaking communities.