The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to improve measurement of patient-reported outcomes. We examined performance of the 29-item PROMIS Profile (PROMIS-29) in persons with rheumatoid arthritis (RA), osteoarthritis (OA), fibromyalgia (FM), and systemic lupus erythematosus (SLE).
Participants in the National Data Bank for Rheumatic Diseases completed the PROMIS-29, which includes 4-item forms for 7 PROMIS domains. Scales were scored and converted to T scores. Distributions of scale scores were examined, convergent and known-groups validity was tested, and differences in scores from online versus paper questionnaires were examined.
Sample sizes were 4,346 for RA, 727 for OA, 241 for FM, and 240 for SLE. Participants were predominantly female, with a mean disease duration ≥20 years, and were ages ∼60 years. Large ceiling effects occurred for some PROMIS-29 scales. Correlations of PROMIS-29 scores with scales measuring similar constructs ranged from high to moderate for RA, OA, and SLE; correlations for FM were markedly lower for some scales. Consistent patterns of worsening PROMIS-29 scores with increasing disease severity or declining health status were observed. Differences in scores obtained by online versus paper questionnaires ranged from 0.3 to 2.2 points.
Results provide guarded support for using the PROMIS-29 in these conditions. The PROMIS-29 4-item static forms appear to identify differences among levels of health and to measure constructs similar to those measured by legacy questionnaires. However, large ceiling effects suggest that measurement may be more precise at the "bad" ends of the scales, which may limit responsiveness, and differences by mode of administration appear to exist.