Article

A computerized adaptive test (CAT) provides a way of efficiently
estimating functional status in people with specific impairments. The purpose of this study was to describe meaningful interpretations of functional
status (FS) estimated using a lumbar CAT developed using items from the Back Pain
Functional Scale (BPFS) and selected physical functioning items. Design and
Setting This was a prospective longitudinal cohort study of 17,439 patients with
lumbar spine impairments in 377 outpatient rehabilitation clinics in 30 states.
Outcome Measures Patient self-reports of functional status were assessed using a
lumbar CAT (0-100 scale). METHODS: Outcome data were interpreted using 4 methods.
First, the standard error of the estimate was used to construct a 95% confidence
interval for each CAT estimated score. Second, percentile ranks of FS scores were
presented. Third, 2 threshold approaches were used to define individual
patient-level change: minimal detectable change (MDC) and clinically important
change. Fourth, a functional staging model, the Back Pain Function Classification
System (BPFCS), was developed and applied. RESULTS: On average, precision of a
single score was estimated by FS score+/-4. Based on score distribution, 25th,
50th and 75th percentile ranks corresponded to intake FS scores of 44, 51, and
59, and discharge FS scores of 54, 62, and 74, respectively. An MDC(95) value of
8 or more represented statistically reliable change. Receiver operating
characteristic analyses supported that changes in FS scores of 5 or more
represented minimal clinically important improvement. The BPFCS appeared
clinically logical and provided insight for clinical interpretation of patient
progress. LIMITATIONS: The BPFCS should be assessed for validity using
prospective designs. CONCLUSIONS: Results may improve clinical interpretation of
CAT-generated outcome measures and assist clinicians using patient-reported
outcomes during physical therapist practice.

Langue : ANGLAIS