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Computer adaptive testing represents new paradigm for assessing patient outcomes
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Using a computerized adaptive testing approach to select questions from a lower extremity item bank reduced patient burden and improved precision compared with two commonly used foot and ankle scales.
“We have proven to ourselves that we have a way forward that is low patient burden, low cost, Internet connected, and that hopefully, will be the future of our field,”
While measuring, reporting and comparing outcomes are critical to improving health care delivery, current outcome measurement paradigms are problematic, Saltzman said. They require the collection of unnecessary information, are burdensome to the patient and have validity/reliability issues. In addition, these paradigms have poor Internet technology support and can interfere with clinical practice.
These issues prompted the National Institutes of Health to develop the Patient-Reported Outcomes Measurement Information System (PROMIS). This 124-item physical function bank facilitates computerized adaptive testing (CAT).
Comparison with other scales
From PROMIS, Saltzman and colleagues extracted a 79-item lower extremity (LE) bank, with particular relevance to foot and ankle problems. They compared their LE CAT with two widely accepted scales — the Foot and Function Index (FFI) and the sport subscale of the Foot and Ankle Ability Measure (FAAM). They studied average time for completion, reliability and precision across the range of lower extremity function.
Charles L. Saltzman
In all, 287 foot and ankle surgery patients completed questionnaires that were administered on iPads. Mean patient age was 47.5 years, 60% were men and more than 60% described their daily activities as heavy labor or mostly walking or standing. Of the patients, 12% had rheumatoid arthritis, 28% had hip pain or deformity in the hips, thighs or knees that limited their activity; 29% noted pain or deformity in the opposite foot or ankle that restricted activities.
Reliability and precision
On average, it took patients 1 minute to complete the LE CAT, 2 minutes seconds to complete the sports FAAM and 4 minutes to complete the FFI.
“We were able to get it under a minute, which we think reduces the burden on the patient,” Saltzman said.
Results revealed exceptionally high item and person reliabilities for the LE CAT (0.96), FFI (0.99) and the FAAM (0.98), Saltzman said.
“In terms of precision, they were all good in the middle, and all precise, it turns out,” he said.
The LE CAT achieved the best overall precision across the entire range of physical function, Saltzman said. Although all three tests had relatively good precision in the middle and part of the upper range of function, he noted that only the LE CAT maintained precision in the lower range of function. – by Colleen Owens
References:
Saltzman CL. A new paradigm for patient-reported outcomes assessment in foot and ankle research: Computerized adaptive testing. Presented at: American Orthopaedic Foot and Ankle Society Annual Meeting; June 21-23, 2012; San Diego.
For more information:
Charles L. Saltzman, MD, can be reached at can be reached at the Department of Orthopedics, University of Utah, 590 Wakara Way, Salt Lake City. UT 84108; email: charles-Saltzman@uiowa.edu.
Disclosure: Saltzman has no relevant financial disclosures.