Computerized adaptive test for patients with lumbar spine impairments produced valid and responsive measures of function.
METHODS
Outcomes instrument validation study.


OBJECTIVE
We evaluated administrative efficiency and psychometric adequacy of a computerized adaptive test (CAT) for patients with lumbar spine impairments seeking rehabilitation in outpatient therapy clinics.


BACKGROUND
CATs promise efficient outcomes data collection in clinical applications with little loss of measurement precision compared to paper and pencil surveys. The lumbar CAT has been developed and simulated and is currently used routinely in therapy clinics. The CAT has not been assessed for administrative efficiency, and the outcomes measures estimated using the CAT have not been assessed using prospective data collection for validity, sensitivity to change, or responsiveness.


METHODS
Data from 17,439 patients with lumbar spine impairments receiving outpatient rehabilitation in 377 clinics in 30 states (United States) were analyzed. We evaluated efficiency of routine CAT administration and assessed construct validity, sensitivity to change, and responsiveness of CAT measures of lumbar functional status (FS).


RESULTS
On average, patients took less than 2 minutes (standard deviation <1 minute) to answer 7 CAT items (standard deviation, 3), which produced precise estimates of FS that adequately covered the content range with negligible floor and ceiling effects. Patients who were older had more chronic symptoms, had more surgeries, had more comorbidities, and did not exercise before receiving rehabilitation reported worse discharge FS. A total of 66% of patients obtained statistically significant change (95% confidence interval minimal detectable change) at discharge. Change of 5 FS units (scale, 0-100) represented minimal clinically important improvement, which 70% of patients obtained. Minimal detectable change and minimal clinically important improvement were associated with intake FS.


CONCLUSIONS
We concluded the lumbar CAT administration was efficient, and CAT FS measures were precise, valid, sensitive, and responsive, supporting lumbar CAT use in clinical and research applications.
Hart
Dennis L
DL
Focus On Therapeutic Outcomes, Inc, Knoxville, TN, USA. hart@fotoinc.com
Werneke
Mark W
MW
Wang
Ying-Chih
YC
Stratford
Paul W
PW
Mioduski
Jerome E
JE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000554:Ambulatory Care Facilities; D016009:Chi-Square Distribution; D003936:Diagnosis, Computer-Assisted; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011594:Psychometrics; D015203:Reproducibility of Results; D013122:Spinal Diseases / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D011795:Surveys and Questionnaires; D014481:United States; D055815:Young Adult