Abstract
Study designProspective observational multicenter cohort study.ObjectivesTo determine Minimal Clinically Important Difference (MCID) of AO Spine PROST (Patient Reported Outcome Spine Trauma) and conducting a long-term prospective validation.MethodsData were collected from a prospective observational international multicenter cohort study. Adults (18-65) with acute thoracolumbar (TL) burst fractures without neurologic deficits were enrolled, and followed for up to 2 years. Patients completed the AO Spine PROST, Oswestry Disability Index (ODI), EQ-5D, and Pain NRS. Characteristics were analyzed using descriptive statistics, MCID for PROST with distribution-based approach using the standard deviation (SD) of change in scores. Floor and ceiling effects were also evaluated. Internal consistency (Cronbach's alpha, item-total correlation coefficient (ITCC) and pairwise Spearman correlation), construct validity (Pearson correlations (r(s)) with ODI, EQ-5D, Pain NRS), and responsiveness (effect sizes (ES) and standardized response mean (SRM)) were assessed.ResultsNinety-three patients were included. MCID for a moderate change (0.5*SD) in PROST score was 10.6. No floor or ceiling effects were observed. Internal consistency was high (Cronbach's α = 0.9-1.0 and acceptable ITCC). PROST scores strongly correlated with ODI (rs = -0.67 to -0.89; P < .001), but correlations with EQ-5D were weak (r(s) = -0.29 to 0.05; P > .005), except at 1-year follow-up. No consistent pattern was found with Pain NRS. Responsiveness was very good (ES = 3.2, SRM = 3.1; P < .001).ConclusionsThe AO Spine PROST identified an MCID of 10.6 as indicative of a moderate clinically meaningful change. The instrument also showed strong internal consistency, construct validity, and excellent responsiveness in long-term follow-up.