Reliability and Construct Validity of Patient-Reported Outcome Measurement Information System Physical Function in Patients With Peripheral Artery Disease

The construct validity of the National Institutes of Health-developed Patient-Reported Outcome Measurement Information System physical function (PROMIS-PF) instrument has not been established in patients with peripheral artery disease (PAD). This study evaluates the reliability and construct validity of PROMIS-PF compared to general and PAD-specific measures. Patients with PAD were recruited at a large academic medical center and completed PROMIS-PF, 36-item short-form (SF-36), Vascular Quality of Life (VascuQoL), walking impairment questionnaire (WIQ), and PROMIS-depression instruments at two time points. Intraclass correlation coefficients assessed test-retest reliability. Spearman rank correlations between PROMIS-PF and similar functional measures evaluated convergent validity, while emotional wellbeing measures served as a discriminant comparison. Twenty-one patients completed questionnaires for both time points with a mean age of 71.5 ± 8.2 y. The cohort was 33% female, with 53% living in moderate or high areas of deprivation. Nineteen percent had chronic limb ischemia, and 76% underwent prior revascularization for PAD. The reliability of the PROMIS-PF was 0.96 (confidence interval [CI] 0.89-0.98) compared to 0.96 (CI 0.92-0.98), 0.95 (0.91-0.98), and 0.79 (CI 0.50-0.92) for the VascuQoL, SF-36 physical function component score, and WIQ, respectively. PROMIS-PF had the strongest correlations with the WIQ (rho = 0.86, P < 0.0001) and VascuQoL (0.85, P < 0.0001) and had the lowest correlation with the SF-36 emotional wellbeing component score (0.15, P = 0.52). PROMIS-PF is a reliable and valid measure of physical function in PAD, demonstrating strong correlations with PAD-specific function measures and discriminant validity with unrelated constructs. These findings support its use in clinical research and PAD patient care.