Lumbar Computerized Adaptive Test and Modified Oswestry Low Back Pain Disability Questionnaire: Relative Validity and Important Change

Study Design Retrospective analysis of longitudinal, observational cohort data. Objectives To compare discriminating ability and minimal clinically important improvement (MCII) calculated using functional status (FS) measures estimated from the lumbar computerized adaptive test (LCAT) and Modified Oswestry Low Back Pain Disability Questionnaire (ODQ). Background The LCAT and ODQ are commonly used to estimate FS in patients seeking outpatient therapy but have not been compared directly. Methods Data from 8198 adult patients who completed the LCAT and ODQ at intake were analyzed, 3379 (41%) of whom completed both surveys at discharge. Global ratings of change data were available for 980 patients. Discriminating ability of FS estimates from the LCAT and ODQ was estimated using relative validity, calculated by dividing F values from LCAT and ODQ analyses of covariance for important risk-adjustment variables. MCII was estimated using receiver-operating-characteristic analyses by quartiles of intake FS values, ...