Purpose: To produce a cross-culturally adapted and validated Turkish version of The Core Outcome Measure Index (COMI) Back questionnaire.
Methods: Ninety-six Turkish-speaking patients with non-specific low back pain (LBP) were recruited from orthopedic and physical therapy outpatient clinics in a public hospital. They completed a booklet of questionnaires containing Turkish version of COMI, adjectival pain scale, Roland Morris disability questionnaire, European 5 Dimension Questionnaire and brief version of World Health Organization Quality of Life Questionnaire. Within following 7-14 days, 67 patients, reported no or minimal changes in their back pain status, completed the Turkish COMI again to assess reproducibility.
Results: Data quality was good with very few missing answers. COMI summary index score displayed 3% floor effects and no ceiling effects. The correlations between the COMI summary index score and each of the full instrument whole scores were found to be excellent to very good (ρ = - 0.81 to 0.74). Reliability expressed as intraclass correlation coefficient (ICC) was 0.95 (95% CI 0.91-0.97). Standard error of measurement (SEMagreement) was acceptable at 0.41 and the minimum detectable change (MDC95%) was 1.14.
Conclusion: Turkish version of the COMI has acceptable psychometric properties. It is a valid and reliable instrument and cross-culturally adapted, in accordance with established guidelines, for the use by Turkish-speaking patients. It can be recommended for use in evaluation of patients with chronic LBP in daily practice, in international multicenter studies and in spine registry systems.
Keywords: COMI; Cross-cultural adaptation; Low back pain; Questionnaire.