Differential impact of disease activity and damage on health-related quality of life in patients with systemic lupus erythematosus.

Background: To study the association between disease activity, disease-related organ damage and health-related quality of life (HRQoL) among Asian patients with systemic lupus erythematosus (SLE).

Methods: We prospectively recruited adult SLE patients from a single tertiary center and followed them three-monthly. We recorded the SLE Disease Activity Index 2000 (SLEDAI-2K) at each visit. SLICC-ACR damage index (SDI) and HRQoL (Medical Outcomes Survey Short Form 36 (SF-36)) were recorded annually. We evaluated the association between SLEDAI-2K and SDI with SF-36 physical (PCS) and mental (MCS) component scores using linear mixed effect models.

Results: We studied 198 patients, comprising Chinese, Malays and Indians. The mean (SD) age at enrollment was 47.1 (12.5) years. The baseline median (IQR) SLEDAI-2k was 2 (0-4). While the mean PCS improved significantly in the second and third year, MCS was unchanged. In the multivariable mixed model analysis, SDI, but not SLEDAI-2k, was significantly associated with poorer PCS (estimate of coefficient (SE) -0.81 (0.29), p < .01). Conversely, SLEDAI-2k, but not SDI, was negatively associated with MCS (estimate of coefficient (SE) -0.36 (0.17), p = .04).

Conclusions: In this cohort of multi-ethnic Asian SLE patients, disease activity is associated with poorer mental, but not physical, HRQoL; whereas disease-related damage is associated with poorer physical, but not mental HRQoL. Our findings suggest a need to differentially approach the impaired HRQoL in SLE patients at different phases of disease; possibly by treating disease activity in patients with impaired mental HRQoL and addressing disease-related damage in patients with impaired physical functioning.