Quality of life and its determinants in established rheumatoid arthritis

Abstract

Background/purpose: Health related quality of life utility (HRQOL) measures such as the European Quality of Life (EQ5D) index are country specific and have not previously been well described in Asian rheumatoid arthritis (RA) patients. We assessed the EQ5D‐index, its determinants, predictors and changes over time in RA patients in Singapore (SG).

Methods: Data from participants of a randomised controlled trial of a multidisciplinary RA clinic were analysed. Data were collected by face‐to‐face questionnaires, review of medical records and joint counts by a standardised assessor.

Results: 131 patients (86.3% female, 53.4% Chinese, age 54.4 ± 12.7 years) of median (IQR) disease duration 5.5 (2.4, 11.0) years were followed for 6 months. The mean (SD) baseline EQ5D‐SG‐index was 0.74 (0.28) (SG population mean 0.95) and the median (IQR) EQ5D visual analogue scale (VAS, 0–100) for overall health‐state was 65 (50, 80) (Figure 1B). Pain was the biggest driver of the EQ5D (Figure 1A). There was a strong correlation between EQ5D‐SG‐index and pain VAS (r = −0.53), physical function as measured by the modified health assessment questionnaire (mHAQ) (r = −0.66) and patient global VAS (r = −0.43), all P < 0.001, confirming face validity of the EQ5D‐SG‐index. Disease activity (DAS28‐ESR) (OR = 1.7, 95%CI = 1.14–2.61, P < 0.01) and coping VAS (0–10, 10 being worst) (OR 1.50 95%CI = 1.22–1.86, P < 0.001) were significant predictors of poor baseline EQ5D‐SG‐index. Age, race, gender, education level, smoking status, body mass index (BMI) and disease duration were not predictors. EQ5D health‐states and EQ5D‐VAS improved after 6 months (Figure 1C, D). On multivariate analysis, the strongest predictors of a minimum clinically significant improvement of 0.1 in the EQ5D‐SG‐index and of 20 points on the EQ5D VAS were a low baseline index (OR 0.61, 95% CI = 0.47–0.79, P < 0.001) and VAS (OR 0.86, 95% CI = 0.81–0.91, P < 0.001), respectively. Conclusion: HRQOL in patients with established RA is impacted by modifiable factors such as disease activity and coping, and can improve over time.