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

Abstract

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). Conclusion 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.