Background The Patient-Reported Outcomes Measurement Information System (PROMIS®) initiative is a cooperative research program designed to develop, evaluate, and standardize item banks to measure patient-reported outcomes across medical conditions. The PROMIS-29 measure contains 29 items, which include four items each for domains reflecting physical function, anxiety, depression, fatigue, sleep disturbance, pain interference, and ability to perform social roles, plus a single item on pain intensity. Scores are standardized with a mean of 50 and standard deviation (SD) of 10. Higher scores represent more of the domain being measured (e.g., greater sleep disturbance, greater ability to perform social roles).
Objectives To examine feasibility and construct validity of the PROMIS29 in patients with systemic sclerosis (SSc) enrolled in a large multinational study.
Methods English-speaking patients with SSc and ≥18 years of age were enrolled in the Scleroderma Patient-centered Intervention Network (SPIN) Cohort between April 2014 and January 2015 from 17 centers across Canada, the USA and the UK. Baseline medical data are provided by the enrolling physician, and SPIN Cohort patients complete outcome measures online every 3 months. Patients were included in the analyses if they completed at least one PROMIS-29 domain at baseline. Floor and ceiling effects were defined as >15% of patients having the lowest or highest possible domain score, respectively. To examine convergent validity of domains, hypotheses were formulated a-priori about the associations of domains and legacy measures. The magnitude of the correlations was interpreted as small (|r| ≤0.3), moderate (0.3 < |r| <0.5), or large (|r| ≥0.5).
Results In total, 376 patients were included in analyses. Mean age was 55.1 years (SD=11.9) and mean time since onset of the first non-Raynaud symptom was 14.4 years (SD=11.8). Most patients were female (n=329, 87.5%) and diagnosed with limited SSc (n=207, 55.1%). Means for the PROMIS-29 domains were: function 42.4 (SD=8.7), anxiety 51.8 (SD=10.1), depression 50.9 (SD=9.3), fatigue 56.2 (SD=11.4), sleep 52.0 (SD=5.2), roles 47.4 (SD=9.5), pain interference 55.9 (SD=9.8), and pain intensity 3.8 (SD=2.7). There was a floor effect for anxiety (33.8%) and depression (37.7%), and ceiling effects for function (19.1%), roles (15.1%) and pain interference (24%). Most hypotheses were confirmed (7 of 9) and all were in the hypothesized direction (Table 1).
Conclusions Results of our study support the construct validity of the PROMIS-29 in patients with SSc. Future studies should examine the influence of floor- and ceiling effects for some domains, as well as other psychometric properties of the measure.
Disclosure of Interest None declared