Correlation between disease activity and patient-reported health-related quality of life in rheumatoid arthritis: a cross-sectional study.

OBJECTIVE: We aimed to provide a comprehensive assessment of health-related quality of life (HRQoL) in patients with rheumatoid arthritis (RA) of different activities and to evaluate the correlation between clinical activity measures and HRQoL instruments. This research also analysed the extent to which different aspects of HRQoL (physical, psychological and social) were affected.

DESIGN: Cross-sectional, observational, non-interventional study.

SETTING: The study was conducted at the Department of Rheumatology and Immunology, Qilu Hospital, Shandong University.

METHODS: From December 2019 to October 2020, a total of 340 RA patients participated in the survey using convenient sampling. Three generic instruments, EQ-5D-5L,SF-12 and the AQoL-4D, as well as an RA-specific instrument,the Stanford Health Assessment Questionnaire Disability Index (HAQ-DI), were administered to assess patients' HRQoL. The Disease Activity Score 28-Erythrocyte Sedimentation Rate (DAS28-ESR) was used by doctors to measure patients' clinical activity. Multivariable linear regression was used to compare patients' HRQoL across different levels of activity. Spearman's correlation was used to assess the correlation between doctor-reported clinical activity and HRQoL.

RESULTS: A total of 314 patients with RA participated in this study. The mean score of HAQ-DI was 0.87 (SD: 0.91). Using patients in the clinical remission group as a reference, patients in the moderate and high disease activity groups showed significantly reduced health state utility values and HRQoL scores (all p<0.05). On the contrary, there was an increase in HAQ-DI scores, indicating more impairment (p<0.05). All instruments included in the study tended to differentiate disease activity based on multiple criteria, with scores showing a moderate to strong correlation with RA activity (|rs |=0.50 to 0.65). Among them, the disease-specific instrument had the highest correlation.

CONCLUSIONS: RA can have considerable impairment on patients' HRQoL, both in terms of physical and psychosocial functioning. Given the strong correlation between clinical activity and HRQoL scores, and the fact that HRQoL can be an important clinical supplement. The EQ-5D-5L is probably the most appropriate generic measurement instrument for measuring HRQoL in RA patients.