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, and areas under the curves were compared. RESULTS: Relative validity ratios favored the LCAT for age (3.7; 95% confidence interval [CI]: 2.0, 8.9), acuity (1.3; 95% CI: 1.1, 1.6), comorbidities (1.8; 95% CI: 1.3, 2.6), and surgical history (1.8; 95% CI: 1.2, 2.9). MCII cut scores per quartile favored the LCAT. Receiver-operating-characteristic areas under the curves were not different. CONCLUSION: FS measures estimated by both questionnaires had similar psychometric characteristics. The LCAT FS estimates tended to be more discriminating than ODQ FS estimates. MCII cut scores by quartile of intake FS favored the LCAT. Given the need to be efficient and precise in estimating measures of FS, particularly in older patients, results favor the LCAT in busy, automated outpatient therapy clinics, which are increasingly serving an aging population.

J Orthop Sports Phys Ther 2012;42(6):541-551, Epub 19 April 2012. doi:10.2519/jospt.2012.3942

KEY WORDS: computerized adaptive testing, lumbar spine, minimal clinically important difference, Oswestry, relative validity

STUDY DESIGN: Prospective cohort study of 10 287 patients with foot/ankle impairments receiving outpatient physical therapy. OBJECTIVES: To describe meaningful interpretations of functional status (FS) outcomes measures, estimated using a body-part–specific computerized adaptive test (CAT). BACKGROUND: Increased use of CATs to generate outcome measures in rehabilitation has stimulated questions concerning score interpretation. Identifying meaningful intra-individual change and reporting clinical interpretation of those generated outcomes are essential to advance the quality of rehabilitation practice. METHODS: We performed 4 approaches to clinically interpret outcomes data. First, we used the standard error of the estimate to construct a 90% confidence interval for each CAT estimated score. Second, we presented the percentile rank of FS scores. Third, we used 2 threshold approaches to define individual-patient-level change: statistically reliable change and clinically important change. Last, we illustrated a functional staging method. RESULTS: Precision of a single score was estimated by an FS score of ±4. Based on score distribution, percentile ranks at 25th, 50th, and 75th percentiles corresponded to intake FS scores of 38, 47, and 57, and discharge FS scores of 52, 64, and 77, respectively. Minimal detectable change supported 7 or more FS change units out of 100 represented statistically reliable change, and ROC analyses supported 8 or more FS change units represented minimal clinically important improvement. Using a functional staging system, we established 5 hierarchical functional status levels. CONCLUSION: CAT-generated outcome measures can be interpreted to improve clinical interpretation and to assist clinicians in using patient-reported outcomes during therapy practice.

J Orthop Sports Phys Ther 2009;39(10):753-764. doi:10.2519/jospt.2009.3122

KEY WORDS: assessment of patient-reported outcomes, computerized adaptive testing, Lower Extremity Functional Scale, outpatient rehabilitation