The discordance between patient global assessment (PGA) and physician global assessment (PhGA) of rheumatoid arthritis (RA) disease activity may be problematic in clinical practice. The aim of this study was to identify determinants of this discordance using a nationwide RA database in Japan (NinJa) with special attention to large joint involvement.
We investigated 12 043 adults with RA and used a discordance cutoff of 3 cm. Large joint involvement was investigated using novel joint indices (x, y, z), where x and y were the indices for upper and lower joints, respectively, and z was for large joint predominance. Predictors of PGA-PhGA discordance and determinants of PGA and PhGA were analyzed by multivariate logistic and linear regression models, respectively.
Multivariate logistic regression identified age, pain and high modified Health Assessment Questionnaire score as predictors of positive discordance (PGA ≥ PhGA), whereas parameters of disease activity in RA (C-reactive protein, x and y), class 3-4 functional status, and z were found to predict against positive discordance. Linear regression analysis revealed that PGA was mainly determined by pain, whereas PhGA was determined by various other factors.
RA care providers should focus on pain and functional disability to decrease PGA-PhGA discordance. High disease activity and large joint involvement decreased PGA-PhGA discordance, indicating that the number and distribution of affected joints influenced the perception of disease activity by patients with RA and their physicians.