Clinical Interpretation of Computerized Adaptive Test–Generated Outcome Measures in Patients With Knee Impairments

Wang Y-C, Hart DL, Stratford PW, Mioduski JE. Clinical interpretation of computerized adaptive test–generated outcome measures in patients with knee impairments.ObjectiveTo describe meaningful interpretations of functional status (FS) outcomes measures estimated using a body-part specific computerized adaptive test (CAT).DesignA prospective observational cohort study.SettingOutpatient physical therapy clinics (291 clinics) in 30 U.S. states.ParticipantsSample of 21,896 patients with knee impairments receiving outpatient physical therapy.InterventionsNot applicable.Main Outcome MeasureFS estimated using CAT administration.ResultsWe investigated 4 approaches to clinically meaningful interpretations of outcomes data: (1) 95% confidence interval for each score estimate, (2) percentile rank of FS scores, (3) responsiveness, and (4) functional staging. Overall, precision of a single score was estimated by FS score ±5. Based on score distribution, percentile ranks at 25th, 50th, and 75th percentiles corresponded to intake FS scores of 33, 42, and 51 and discharge FS scores of 51, 61, and 74, respectively. Results showed that 9 or higher FS change units represented statistically and clinically important improvement. Patients were classified into 6 hierarchical levels of FS using functional staging.ConclusionsResults suggest how CAT-generated outcomes measures can be interpreted to assist clinicians and patients during rehabilitation.