IgA nephropathy (IgAN) is a progressive disease in which an antibody called immunoglobulin A (IgA) builds up in your kidneys. Over time, this build-up results in inflammation that can hinder your kidneys’ ability to filter waste from your blood. 

Statistics show that, in North America and Western Europe at least, IgAN affects more than twice as many men as women, but few studies have explored other possible differences in risk factors, clinical features, and long-term outcomes of the condition in men versus women. 

A recent study, led by a team of researchers in Sichuan, China, and published in the journal International Urology and Nephrology, sought to fill these knowledge gaps. 

What The Researchers Did  

Study participants consisted of 475 male and 621 female adult IgAN patients (total=1,096). The researchers assessed participants for clinical disease features and risk factors for comparison. Primary outcomes of interest included:

• A 50% reduction in remaining percentage of kidney function, expressed as estimated glomerular filtration rate (eGFR)
• End-stage kidney disease, defined as either an eGFR of less than 15 or the initiation of dialysis

What They Found

The data showed that, at baseline, male patients had:

• Higher blood pressure 
• Higher levels of uric acid and the protein creatinine in their blood
• Higher levels of protein in their urine
• Lower eGFR

Male patients were also shown to more frequently experience atrophied renal tubules (the tiny tubes that return filtered water and nutrients to the blood), interstitial fibrosis lesions, and vascular lesions. 

The follow-up period, an average of 40.9 months, revealed kidney survival rates in male patients that were significantly lower than those in female patients. 

What It Means

Overall, since male IgAN patients presented with more severe clinical and pathological changes than female patients, and kidney survival rates were also notably lower in male patients, male sex was identified as an independent risk factor for poor outcomes. 

*Wen, D., Tang, Y., Tan, L., Tan, J., et al. (2020, Sep. 17). Sex disparities in IgA nephropathy: a retrospective study in Chinese patients. International Urology and Nephrology.   https://pubmed.ncbi.nlm.nih.gov/32944891/