Objective: To assess reliability, validity, and responsiveness of a 29-item short-form version of the Patient Reported Outcomes Measurement Information System (PROMIS) and a novel “impact score” calculated from those measures.
Design: Prospective cohort study.
Setting: Rural primary care practices.
Subjects: Adults aged ≥ 55 years with chronic musculoskeletal pain, not currently receiving prescription opioids.
Methods: Subjects completed the PROMIS short form at baseline and after 3 months. Patient subsets were compared to assess reliability and responsiveness. Construct validity was tested by comparing baseline scores among patients who were or were not applying for Worker's Compensation; those with higher or lower catastrophizing scores; and those with or without recent falls. Responsiveness was assessed with mean score changes, effect sizes, and standardized response means.
Results: Internal consistency was good to excellent, with Cronbach's alpha between 0.81 and 0.95 for all scales. Among patients who rated their pain as stable, test-retest scores at 3 months were around 0.70 for most scales. PROMIS scores were worse among patients seeking or receiving worker's compensation, those with high catastrophizing scores, and those with recent falls. Among patients rating pain as “much less” at 3 months, absolute effect sizes for the various scales ranged from 0.24 (Depression) to 1.93 (Pain Intensity).
Conclusions: Results indicate that the PROMIS short 29-item form may be useful for the study of patients with chronic musculoskeletal pain. Our findings also support use of the novel “impact score” recommended by the National Institutes of Health (NIH) Task Force on Research Standards for Chronic Low Back Pain.