What does the patient global health assessment in RA really tell us? Contribution of specific dimensions of health‐related quality of life

OBJECTIVE: To estimate the contributions of health-related quality of life domains to the patient global assessment of health (PGA) in RA. METHODS: Data are drawn from baseline visits of two observational RA cohorts. Participants completed patient-reported outcome measures (PROMs) including PGA and Patient-Reported Outcomes Measurement Information System (PROMIS®) measures and clinical data were collected. Factor analysis was used to identify latent variables, and multivariable linear regression was used to estimate determinants of PGA. RESULTS: Patients were mostly female (81%), white (78%), and had established disease (mean 12.3 years (SD 10.7), with 62% in remission or LDA. In Cohort 1 (n=196), two factors emerged: 1) daily function (moderate-strong (i.e., >|0.65| loadings of physical function, pain interference, social participation, and fatigue, and weak (>0.35) loadings of sleep disturbance; and 2) emotional distress (strong loadings of depression and anxiety). In crude analysis, daily function explained up to 53% and emotional distress up to 20% of the variance in PGA. In both cohorts, in adjusted analyses, daily function and to a much lesser extent swollen joint count independently predicted PGA; age was inversely related to PGA in Cohort 1 only. CONCLUSION: These findings suggest that in patients with RA, PGA ratings largely reflect the extent to which patients feel they can function in everyday roles and are not impacted by mood. This suggests that higher than expected PGA scores may offer an opportunity to discuss patient expectations regarding roles and activities, and the impact of their RA symptoms on daily function.