Cross-cultural adaptation and validation of the Polish version of the Core Outcome Measures Index for low back pain

Purpose The Core Outcome Measures Index (COMI) is a short, multidimensional outcome scale validated for the use by patients with spinal disorders. It is a recommended instrument in the Spine Society of Europe Spine Tango Registry. The purpose of this study was to produce a cross-culturally adapted and validated Polish COMI. Methods The cross-cultural adaptation was carried out using the established guidelines. One-hundred and sixty-nine patients with chronic low back pain were enrolled, 89 took part in the reproducibility part of the study. Data quality, construct validity and reproducibility were assessed. Results The quality of data was very good with very few missing answers and modest floor effect. Reliability expressed as intraclass correlation coefficient (ICC) was 0.90 (95 % CI 0.85-0.93) for the overall COMI score and for most of the individual core items. The minimum detectable change (MDC95%) was 1.79. Conclusions The Polish version of COMI showed a favorable reproducibility similar to that of previously tested language versions. The COMI scores correlated sufficiently with existing measures. This version of the COMI is a valuable instrument for the use by Polish-speaking patients with spinal disorders.