Sex differences in mortality among patients with lupus nephritis.

Objective: To evaluate the prognostic importance of sex in lupus nephritis (LN).

Methods: A retrospective cohort of 1048 biopsy-confirmed LN patients, diagnosed between January 1, 1996, and December 31, 2018, was analyzed. Demographics, clinical characteristics, laboratory findings, and renal pathology were assessed. The primary outcome was mortality, and the secondary outcomes included doubling of serum creatinine and end-stage renal disease (ESRD). Sex-associated risks were evaluated using Cox regression models.

Results: Among the1048 patients, 178 (17%) were male and 870 (83%) were female. Male patients exhibited more aggressive features: higher blood pressure, earlier disease onset, and elevated levels of serum creatinine (Scr), uric acid, blood urea nitrogen. Intriguingly, male patients also displayed more severe histopathological alterations, such as more total crescents, cellular crescents formations, higher level of glomerular leukocyte infiltration and Activity Index (AI), even when overall renal pathology was comparable between sexes. During a median follow-up of 112 months, mortality was registered in 141 patients (15.3%). Mortality rates were conspicuously higher in males (24.2% males vs. 13.4% females, p = 0.0029). Secondary outcomes did not show significant sex differences. Cox regression analysis highlighted male, age of renal biopsy, eGFR, and Chronicity Index (CI) as independent risk factors for survival in LN patients. Notably, infections emerged as the leading cause of mortality among LN patients, with a significant higher rate in male patients.

Conclusion: In our cohort with LN, there was a higher rate of all-cause mortality and proportion of infection-related death in male. Recognizing and further exploring these sex disparities is crucial for optimized LN patients care.