New paradigm for patient-reported outcomes assessment in foot & ankle research: computerized adaptive testing.

Background: Accurately measuring, reporting and comparing outcomes is essential for improving health care delivery. Current challenges with available health status scales include patient fatigue, floor/ceiling effects and validity/reliability.

Methods: This study compared Patient Reported Outcomes Measurement Information System (PROMIS)-based Lower Extremity Physical Function Computerized Adaptive Test (LE CAT) and two legacy scales -the Foot and Function Index (FFI) and the sport module from the Foot and Ankle Ability Measure (spFAAM) -for 287 patients scheduled for elective foot and ankle surgery. We documented the time required by patients to complete the instrument, instrument precision, and the extent to which each instrument covered the full range of physical functioning across the patient sample.

Results: Average time of test administration: 66 seconds for LE CAT, 130 seconds for spFAAM and 239 seconds for FFI. All three instruments were fairly precise at intermediate physical functioning levels (i.e., Standard Error of Measurement < 0.35), were relatively less precise at the higher trait levels and the LE CAT maintained precision in the lower range while the spFAAM and FFI's had decreased precision. The LE CAT had less floor/ceiling effects than the FFI and the spFAAM.

Conclusion: The LE CAT showed considerable advantage compared to legacy scales for measuring patient-reported outcomes in orthopaedic patients with foot and ankle problems.

Clinical Relevance: A paradigm shift to broader use of PROMIS-based CATs should be considered to improve precision and reduce patient burden with patient-reported outcome measuremen foot and ankle patients.