Detecting anxiety and depression among people with limited literacy living with chronic low back pain in Nigeria: adaptation and validation of the hospital anxiety and depression scale

BACKGROUND: The Hospital Anxiety and Depression Scale (HADS) is one of the most popular measures of anxiety and depression. The original HADS is mostly used in Nigeria precluding people with limited literacy. This study aimed to cross-culturally adapt and psychometrically test the HADS for rural and urban Nigerian Igbo populations with chronic low back pain (CLBP) who have limited literacy. METHODS: The HADS was forward translated, back translated, and appraised. Face and content validity was ensured by pre-testing the translated measure among a convenience sample of twelve rural Nigerian dwellers with CLBP. Reliability utilising Cronbach’s alpha, intraclass correlation coefficient, Bland–Altman plots and minimal detectable change were investigated amongst a convenience sample of 50 people living with CLBP in rural and urban Nigerian communities. Construct validity testing involving correlations between Igbo-HADS and Roland Morris Disability Questionnaire measuring self-reported back pain-specific disability, World Health Organisation Disability Assessment Schedule assessing generic self-reported disability, Fear Avoidance Beliefs Questionnaire measuring fear avoidance beliefs, and eleven-point box scale assessing pain intensity, and exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) among a random sample of 200 adults with CLBP in rural Nigerian communities were conducted. RESULTS: Idioms and colloquialisms were difficult to adapt. Internal consistency was good (α = 0.78) and acceptable (α = 0.67) for anxiety and depression subscales respectively. Intraclass correlation coefficients were very good (ICC ≃ 0.8) for both subscales. Minimal detectable change was 6.23 and 5.06 for anxiety and depression subscales respectively. The Igbo-HADS and the anxiety subscale had strong correlations (≃ 0.7) with generic self-reported disability; moderate correlations (≃ 0.5–0.6) with pain intensity, self-reported back pain-specific disability, and fear avoidance beliefs. The depression subscale had the lowest correlations (≃ 0.3–0.4) with these outcomes. The EFA produced a two-factor structure with cross-loading of items. The CFA showed poor fit indices for the EFA structure, the original two-factor structure, and one-factor structure. CONCLUSION: The HADS may not be suitable for assessing anxiety and depression, or emotional distress in this population due to difficulty achieving cross-cultural equivalence with western idioms; and the expression of emotional distress through somatisation in this culture. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13690-021-00586-4.