Association between disease activity measured by RAPID3 and health-related quality of life in patients with rheumatoid arthritis

Routine assessment of patient index data 3 (RAPID3) is a simple, valid and reliable tool designed to measure disease activity in patients with rheumatoid arthritis (RA). RA causes significant disability and diminishes health-related quality of life (HR-QoL). The aim of this study was to investigate how RAPID3 is related to HR-QoL in patients with RA. In this cross-sectional study performed at the tertiary outpatient clinic 68 consecutive patients (58 females, and 10 males) with established RA were enrolled. RAPID3 and EuroQoL-5D-3L (EQ-5D-3L) were used to measure disease activity and quality of life, respectively. Alongside, demographic and clinical data were obtained, as well as HAQ-DI as a measure of physical function, and Steinbrocker's score for radiographic damage. To test the relationships among RAPID3 and study variables we used the Pearson product-moment correlation coefficient, with the significance was set at P < 0.05. Linear and forward stepwise regression was used to show how variables of interest contributed to RAPID3. The mean value of RAPID3 (standard deviation, SD) was 14.12 (+/- 5.21), while the median (IQR) value of EQ-5D-3L was 0.51 (0.62-0.23). There was a high significant correlation (r = - 0.73) between RAPID3 scores and EQ-5D-3L. Among the other variables of interest, the strongest correlation was found between RAPID3 and intensity of pain (r=0.88), while the EQ-5D-3L and pain were moderately correlated (r = - 0.68). In evaluating the influence of variables of interest on RAPID3, a forward stepwise regression model was constructed to evaluate whether VAS pain, EQ-5D-3L and EQ-VAS predicted RAPID3. The given variables significantly explained approximately 81% of the variation in RAPID3. Based on the results of this study RAPID3, a simple and practical tool to assess disease activity, reflects well HR-QoL in patients with established RA.