Background/Purpose: Systemic lupus erythematosus (SLE) is a disease predominately of young women that disproportionately affects minorities.   Lupus Nephritis (LN) causes major morbidity and mortality in this population.  It is suggested that men with SLE have worse disease outcomes with high rates of LN.  This study was undertaken to identify major clinical differences and outcomes by gender in LN in an urban ethnic population. 

Methods: All LN biopsies at Montefiore Medical Center, Bronx, NY were analyzed from Jan 1997- Jan 2012. All patients met ≥ 4/11 ACR SLE criteria.  We collected demographics, clinical and serologic data and treatment regimens over a 1yr period post biopsy. The primary endpoints were gender differences in time to end stage renal disease (ESRD) as defined by the initiation of dialysis and inclusion in the US Renal Data System and all-cause mortality as reported to the Social Security Administration. 

Results: 207 patients were included: 37 male (M) 170 female (F). Men trended to be diagnosed with SLE earlier (24.6y±14.4 v 28.2y±14.2, p=0.2) and have a shorter disease duration at the time of biopsy (median 1y v 2y, p=0.11). There were no differences with regards to ethnicity: African American 55.6% M v 55.1% F and Hispanic 36.1% M and 37.7% F (p=0.93). Both genders had similar rates of hypertension (p=0.91), diabetes (p=0.80), and cardiovascular disease (p=0.40). At biopsy, men had higher levels of dsDNA antibodies (median 263.9 v 126.3, p=0.007) but there were no difference in median C3 (p=0.74) and C4 levels (p=0.71), mean systolic BP (p=0.71), median serum creatinine (1.1 M v 1.0 F, p=0.23) or median protein to creatinine ratio (2.1 M v 2.2 F, p=0.53). The distribution of LN classes between the genders were similar: class III/IV – 59.5% M v 58.2% F; class V – 27.0% M v 25.3% F; mixed class – 8.1 %M v 12.4% F(p=0.88).

There was no difference in ACEi/ARB (p=0.54), hydroxychloroquine (p=0.72) or steroid use (p=0.14) between the genders. While men tended to get cyclophosphamide induction at higher rates than women (60.0% M v 48.8%F) both genders were mostly maintained on mycophenolate (64.0% M v 65.5% F).

Regardless of subtle, though not statistically significant, differences in treatment there was no difference between rates of ESRD (log rank, p=0.85) or all-cause mortality (log rank p=0.36) between the genders.

Conclusion: Our study suggests that there are few clinical differences between men and women lupus nephritis in this population.  Race/ethnicity/socioeconomic status may play a greater role than gender when looking at disease severity and outcomes.