Objectives: To evaluate the validity of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function measures using longitudinal data collected in six chronic health conditions.
Study design and setting: Individuals with rheumatoid arthritis (RA), major depressive disorder (MDD), back pain, chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF), and cancer completed the PROMIS Physical Function computerized adaptive test or fixed-length short form at baseline and at the end of clinically relevant follow-up intervals. Anchor items were also administered to assess change in physical function and general health. Linear mixed-effects models and standardized response means were estimated at baseline and follow-up.
Results: A total of 1,415 individuals participated (COPD n = 121; CHF n = 57; back pain n = 218; MDD n = 196; RA n = 521; cancer n = 302). The PROMIS Physical Function scores improved significantly for treatment of CHF and back pain patients but not for patients with MDD or COPD. Most of the patient subsamples that reported improvement or worsening on the anchors showed a corresponding positive or negative change in PROMIS Physical Function.
Conclusion: This study provides evidence that the PROMIS Physical Function measures are sensitive to change in intervention studies where physical function is expected to change and able to distinguish among different clinical samples. The results inform the estimation of meaningful change, enabling comparative effectiveness research.
Keywords: Chronic conditions; Item bank; PROMIS; Patient-reported outcome; Physical function; Validity.
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