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.