Gender differences in the clinical features and quality of life of Japanese patients with systemic lupus erythematosus: a cross-sectional study based on the LUNA registry

BACKGROUND: Gender differences in clinical manifestations and disease progression of systemic lupus erythematosus (SLE) have been well documented; however, there is a paucity of literature on the gender differences in the quality of life (QOL) of patients with SLE, especially in the context of organ-specific damage. This study aimed to explore gender differences in the clinical features and patient-reported outcomes among Japanese patients with SLE, with particular focus on the effect of joint and cardiac damage on gender-based disparities in QOL: previous studies have shown that articular and cardiac damage are associated with impaired health-related HR QOL (HRQOL). METHODS: In this retrospective, cross-sectional multicenter cohort study, we used data from 1297 Japanese patients with SLE (159 males (12.3%) and 1138 females (87.7%)) enrolled in a nationwide multicenter registry (LUNA), and compared the clinical variables, organ damage scores (SLICC/ACR Damage Index [SDI]), and QOL (assessed using the LupusPRO questionnaire) between the sexes. Additionally, subgroup analyses were performed for patients with arthritis/joint damage, cardiac damage, and according to disease activity (lupus low disease activity state, LLDAS). RESULTS: The median age of our cohort was 51 years (interquartile range, 40-63 years). Male patients had a shorter disease duration and were older at disease onset than females. The disease activity scores were slightly lower in male patients, whereas SDI was slightly higher in females. Male patients exhibited lower rates of articular/joint damage (1.26% versus 4.66%, p = 0.046) but higher rates of cardiac damage (11.3% versus 7.15%, p = 0.015) than females. The LupusPRO indicated higher HRQOL scores for male patients with SLE than female patients (87.4 versus 80.5, p = 0.001); however, the difference of HRQOL became unclear between both sexes in the presence of arthritis/joint damage and cardiac damage. CONCLUSION: Japanese male patients with SLE have a relatively higher HRQOL than females; however, this change became unclear in patients with SLE who had joint or cardiac damage. Further investigations are needed to clarify exact contributing factors for better HRQOL in male patients with SLE.