Long-Term Reliability and Validity of the AO Spine PROST (Patient-Reported Outcome Spine Trauma)

Abstract

Cross-sectional validation study. To validate the AO Spine PROST at a minimum of twelve months post-trauma and to evaluate patient characteristics, types of spine fractures and treatment strategies as determinants of AO Spine PROST scores. The reliability and validity of the AO Spine PROST (Patient Reported Outcome Spine Trauma) as a measure of health-related quality of life (HRQoL) for more than twelve months after onset of spine trauma is unclear. Patients with a traumatic spine injury were recruited from a level-1 trauma center. They were asked to complete the AO Spine PROST, EuroQoL 5D-5L (EQ-5D-5L), and either Oswestry Disability Index (ODI) or Neck Disability Index (NDI) for concurrent validity. Internal consistency was assessed by calculating Cronbach's α and item-total correlation coefficients (ITCCs). Test-retest reliability was evaluated using Intraclass Correlation Coefficients (ICCs). Spearman correlation tests were performed for the AO Spine PROST in correlation with the EQ-5D-5L, and either ODI or NDI. Determinants for AO Spine PROST score were analyzed using multivariate regression models. A total of 175 patients participated in the cross-sectional arm and 49 in the test-retest arm of the study. Median duration of follow-up was 94.5 months. No floor or ceiling effects were seen. Internal consistency was excellent (α=0.98, ITCC 0.73-0.91) as well as test-retest reliability (ICC=0.81). Satisfactory correlations were seen for the EQ-5D-5L (0.76; P<0.001), ODI (0.69; P<0.001) and NDI (0.68; P<0.001) with the AO Spine PROST. Multivariate linear regression models showed that having ≥1 comorbidities, duration of return to work within the range of 7-43 months and no return to work were significant independent determinants for a worse AO Spine PROST score. Very good long-term reliability and validity results were found for the AO Spine PROST.