Sex differences in mortality among patients with lupus nephritis

1. Males with lupus nephritis had higher all-cause mortality and proportion of infection-related death compared to females. 

Evidence Rating Level: 2 (Good)

Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE) that may result in end-stage renal disease (ESRD). Sex differences play a role in chronic kidney diseases and SLE with more females being affected (female-to-male ratio 9:1) but males exhibiting more severe kidney involvement. As research on sex differences in LN has focused on Western populations, knowledge gaps exist in the prognostic significance of sex in LN among other ethnic groups. As the prognostic importance of sex in LN remains controversial, this study thus investigated the prognostic importance of sex in LN in a Chinese population. This retrospective cohort study analyzed biopsy-confirmed LN patients, diagnosed between January 1, 1996, and December 31, 2018. The primary outcome was mortality, and the secondary outcomes included doubling of serum creatinine and end-stage renal disease (ESRD). Among the 1048 patients included in the study, 178 (17%) were male (mean age = 25 years (17-35)) and 870 (83%) were female (mean age = 28 years (21-37)). Male patients exhibited more aggressive features such as earlier disease onset, higher blood pressure, and elevated levels of many biomarkers of kidney dysfunction (p < 0.05). Despite comparable distribution of LN pathological classifications between sexes, male patients exhibited a greater number of renal lesions, including more total crescents, cellular crescent formations, higher levels of glomerular leukocyte infiltration, and Activity Index (AI) (p < 0.05). During a median follow-up period of 112 months, death was reported in 141 patients (15.3%). The mortality rate was higher among male patients (24.2% of all males) compared to females (13.5% of all females). No sex differences were observed for doubling of serum creatine and ESRD. Independent risk factors for survival in LN patients included being male (hazard ratio (HR) 95%CI = 1.79 (1.22–2.64)), older age of renal biopsy (HR 95% = 1.02 (CI 1.01–1.04)), and increased Chronicity Index (HR 95%CI = 1.18 (1.07–1.3)). Infections were the leading causes of mortality, with a higher proportion of infection-related deaths observed for male patients (55.3% for male, 35% for female, p = 0.007). Overall, males in the study cohort had higher all-cause mortality and proportion of infection-related death. Future research is needed to elucidate the sex disparities to optimize care for patients with LN.

Click to read the study in BMC Medicine

Image: PD

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