A computerized adaptive test for patients with hip impairments produced valid and responsive measures of function.
OBJECTIVE
To describe the use of a computerized adaptive test (CAT) in routine clinical practice and evaluate content coverage and construct validity, sensitivity to change, and responsiveness of hip CAT functional status (FS) measures.


METHODS
Longitudinal, prospective observational cohort study.


METHODS
Two hundred fifty-seven outpatient rehabilitation clinics in 31 states (United States).


METHODS
Two samples were examined: intake and discharge rehabilitation FS data from patients (N=8714) treated for hip impairments between January 2005 and June 2007 and data from patients (N=444) used to develop the hip CAT were examined for comparison (2002-2004).


METHODS
Not applicable.


METHODS
Hip functional status and global rating of change.


RESULTS
The CAT used on average 7 items to produce precise estimates of FS that adequately covered the content range with negligible floor and slight ceiling effects. Test information functions and SEs supported FS measure precision. FS measures discriminated patients in clinically logical ways. Sixty-one percent of patients obtained discharge FS measures greater than or equal to minimal detectable change (95% confidence intervals). Change of 6 FS units (scale: 0-100) represented minimal clinically important improvement, which 64% of patients obtained.


CONCLUSIONS
The hip CAT was efficient; produced valid, responsive measures of FS for patients receiving therapy for hip impairments; and functioned well in routine clinical application but would benefit from more difficult items.
Hart
Dennis L
DL
Department of Consulting and Research, Focus On Therapeutic Outcomes, Inc, 551 Yopps Cove Rd, White Stone, VA, USA. hart@fotoinc.com
Wang
Ying-Chih
YC
Stratford
Paul W
PW
Mioduski
Jerome E
JE
D000293:Adolescent; D000328:Adult; D000368:Aged; D003936:Diagnosis, Computer-Assisted; D004185:Disability Evaluation; D005240:Feasibility Studies; D005260:Female; D006621:Hip Joint; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis / Q000534:rehabilitation*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011594:Psychometrics; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States