Translation, Cross-cultural Adaptation, and Psychometric Properties of the Hausa Versions of the Numerical Pain Rating Scale and Global Rating of Change Scale in a Low-literate Population With Chronic Low Back Pain

Study Design. Translation, cross-cultural adaptation, and psychometric testing. Objective. To translate, cross-culturally adapt, and validate the Numerical Pain Rating Scale (NPRS) and the Global Rating of Change Scale (GRCS) into Hausa language. Summary of Background Data. The NPRS and GRCS are commonly used patient-reported outcome measures in a variety of pain-related conditions including low back pain. To date, neither the NPRS nor GROC are available in Hausa language. Methods. The Hausa versions of the NPRS (NPRS-H) and GRCS (GRCS-H) were developed using recommended guidelines. The final versions were then administered to 120 patients with chronic low back pain to access their psychometric properties. Reliability assessment included calculations of intraclass correlation coefficient (ICC) and minimal detectable change among the stable group. Construct validity and concurrent validity were assessed using the Spearman rank correlation coefficient. Internal responsiveness was assessed using mean change scores, standardized effect size, and standard response mean. Receiver operating characteristic curves were plotted to determine the external responsiveness of the NPRS-H using the area under the curve, and minimal important change for small, medium, and large improvements. Outcome measures consisted of the Visual Analogue Scale for pain and Oswestry Disability Index. Results. The NPRS-H and GRCS-H were successfully developed. High test-retest reliability was demonstrated for both the NPRS-H (ICC = 0.95) and GRCS-H (ICC = 0.94) with minimal detectable change points of 1.0 and 1.2 respectively. The scales showed moderate to strong correlation with the Visual Analogue Scale for pain and Oswestry Disability Index. The mean change of the NPRS-H scores correlated moderately with the GRCS-H. Both scales demonstrated good internal responsiveness. External responsiveness of the NPRS-H was demonstrated at three levels with area under the curve = 0.875 to 0.972, and minimal important change = 2.5 to 3.5. Conclusions. The NPRS and GRCS were successfully adapted into Hausa language with acceptable reliability, validity, and responsiveness. These measures are appropriate for clinical and research use among Hausa-speaking patients.