Validity and Responsiveness of a 10-Item Patient-Reported Measure of Physical Function in a Rheumatoid Arthritis...

We assessed implementation of the 10-item Patient-Reported Outcomes Measurement Information System (PROMIS) physical function form (PF-10a) in routine practice in a racially and ethnically diverse population with rheumatoid arthritis (RA). Objectives were to determine feasibility of implementing PF-10a in the electronic health record (EHR) and PF-10a validity and longitudinal responsiveness.

Clinical and demographic data were abstracted from EHRs for all RA patients seen at a university-based rheumatology clinic between February 2013 and February 2015. We evaluated floor and ceiling (edge) effects and construct validity of PF-10a in a subgroup of patients with Health Assessment Questionnaire (HAQ) scores (n = 189). We used linear mixed-effects models to assess responsiveness of PF-10a to longitudinal changes in the Clinical Disease Activity Index (CDAI) for patients in the entire clinical cohort, with both scores recorded on at least 2 encounters (n = 326).

Half of the patients were nonwhite, and 15% were non-English speakers. Over a 2-year period, PF10a was successfully implemented; 97% of patients and 89% of encounters had at least 1 measurement performed. PF-10a had fewer ceiling (defined as best) effects than the HAQ (8% versus 22%), and convergent validity was high (r = -0.85). PF-10a was sensitive to expected differences (older versus younger patients, more versus less active disease). Longitudinal changes in PF-10a were highly associated with changes in the CDAI score (P < 0.0001).

PF-10a was feasible to implement in a diverse RA population. It strongly correlates with the HAQ but has fewer ceiling effects and is responsive to changes in RA disease activity, suggesting its validity for use in routine clinical practice.