Correlation and Crosswalks Between Patient-Reported Functional Outcomes and PROMIS Physical Function Among Medically Ill Patients

Objectives: To develop scoring crosswalks between a new multidomain patient-reported outcome measure, the Functional Assessment in Acute Care (FAMCAT), with a Patient-Reported Outcomes Measurement (PROMIS) measure of physical function, and examine correlations with existing legacy instruments. Design: Cross-sectional, single-group design study. Setting: Large, Midwestern academic teaching hospital. Participants: A sample of patients (N=1885; 53% men; average age, 62±16y) hospitalized on the general medical services between May 2016 and June 2017. Intervention: Not applicable. Main Outcome Measures: Scores from the FAMCAT administered via computerized adaptive testing were compared with scores on the 8-item PROMIS Physical Function (PROMIS PF) short form. Results: Correlations with the FAMCAT and the PROMIS PF were strong for initial scores (MCAT_Mobilty: r=0.78, P<.0001; MCAT_DailyAct: r=0.81, P<.0001). The Applied Cognition scale did not demonstrate adequate correlations and thus was not a candidate for crosswalk scores. Although the MCAT_Mobility scale could be initially linked, subsequent analysis did not support a valid crosswalk. Linking criteria were applied with the Daily Activity scale to developing a final concordance table. Conclusions: The FAMCAT Daily Activity scale yielded robust correlations to develop crosswalk scores with the PROMIS PF. The resulting crosswalk conversion metric may be useful to compare outcomes across these constructs for assessing functional abilities among patients on general medical services. The Applied Cognition and Basic Mobility scales did not meet the criteria; therefore, alternate legacy instruments are needed to develop additional crosswalks.