Background/Purpose:

Systemic lupus erythematosus (SLE) is a chronic disease affecting the physical, social, and psychological well-being of patients. Health related quality of life (HRQoL) measures add a new dimension to treatment response. However, their longitudinal correlation with clinical indicators such as disease activity and organ damage are not known. We aimed to determine HRQoL over time in a multi-ethnic Asian SLE cohort and to study its relationship with disease activity and damage.

Methods:

Adult patients with SLE (ACR or SLICC criteria fulfilled) attending rheumatology clinics at our institution are recruited in a longitudinal observational study since 2013.  Demographic and clinical data including SLEDAI-2K are collected at enrollment and every three months while organ damage (SLICC-ACR damage index [SDI]) is assessed annually. HRQoL is measured using SF-36 survey at enrollment and annually. Patients with 4 or more HRQoL measures from enrollment to December 2016 were included in the current analyses. Linear mixed effect model was used to compare the subsequent SF-36 scores with baseline, and among different races. Moreover, linear mixed effect model was used to evaluate the effect of disease activity (SLEDAI-2K) and damage (SDI) on the SF-36 scores, after adjustment for baseline scores, ethnicity, and time. 

Results:

A total of 196 patients were studied; mean ± SD age at enrollment was 47.05 ± 12.54 years, 180 (90.9%) were women. 140 (70.7%), were Chinese; 28 (14.1%) Malays, 17 (8.6%) Indians, and 13 (6.6%) were other races. Majority were non-smokers (91.9%) and 10.1% had a family history of SLE.

Baseline mean ± SD score of physical component summary (PCS) was 47.8 ± 8.2, while mental component summary (MCS) score was 48.5 ± 9.8 (Table 1). The mean PCS improved significantly in second (p<0.008) and third year (p<0.001) as compared to baseline scores while no significant change was noted in MCS scores in second (p<0.76) or third year (p<0.25).

Significant association was noted between PCS and SLEDAI 2K scores (p<0.006). For every unit increase in the SLEDAI-2K, the mean PCS would reduce by 0.808 (95% CI 0.236 – 1.381). SDI was negatively associated with MCS (p<0.035); for every unit increase in SDI, the mean MCS would reduce by 0.363 (95% CI 0.026 – 0.701).  Indian ethnicity was associated with worse MCS scores (p<0.008).

Conclusion:

This study demonstrated that HRQoL improves over time in SLE patients with proper management. Disease activity affects physical health while organ damage dictates psychosocial aspect of life in these patients. Therefore, HRQoL should be considered as an essential outcome measure in management of SLE patients.