Men with ANCA-associated vasculitis (AAV) presenting kidney inflammation are more likely than women to progress into end-stage renal disease, according to Norwegian researchers.
Their study, “Exploring sex-specific differences in the presentation and outcomes of ANCA-associated vasculitis: a nationwide registry-based cohort study,” was published in the journal International Urology and Nephrology.
AAV patients with kidney symptoms are at risk for developing end-stage renal disease and require chronic renal replacement in the form of dialysis or a kidney transplant. But studies suggest that women carry a lower risk for disease worsening than men.
This might have different explanations, including less severe kidney inflammation in women, the fact that women seek care earlier than men, and differences in treatment adhesion.
To shed light on gender differences affecting the risk for end-stage renal disease, researchers at the University of Bergen in Norway collected data from 358 patients (median age 60; 52% of them men) included in the Norwegian Kidney Biopsy Registry between the years 1991 and 2012.
All patients had AAV with renal manifestations, but only 87 of them worsened to end-stage renal disease (ESRD). By the end of the analysis, only 48 ESRD patient were alive.
When examining women and men separately, investigators found that men developed ESRD more frequently than women.
At year one, 90% of women had not progressed to end-stage disease, compared to 81% of men. At year five, the figures were 80% of women and 71% for men.
After adjusting the results for age and other clinical markers, this represented a 2.4-fold higher risk for ESRD in men.
Researchers also found that men and women had a similar disease severity at diagnosis, supporting the hypothesis that these gender differences are “probably caused by sex-specific intrinsic kidney factors and/or sex differences in treatment or response to treatment,” researchers wrote.
Interestingly, while AAV in women was less likely to worsen into chronic liver disease, women did not outlive men, which was surprising to the researchers. They believe that women might be dying before they have the chance of developing severe renal disease, which would a reason for the similar mortality rates.
Still, the process underlying these sex-specific differences in kidney function warrants additional research, the investigators said.