Supplementary Material for: Sex Differences in Kidney Function Decline in the Healthy General Population

Background There are considerable sex and gender differences in the epidemiology of chronic kidney disease (CKD), with CKD stage 3, defined as a glomerular filtration rate (GFR) below 60, being more prevalent in women. This raises questions about whether sex differences in age-related GFR decline contribute to this paradox. Only a few studies have investigated this issue, and most of these studies used estimated GFR (eGFR) based on creatinine (eGFRcrea) or cystatin C (eGFRcys). Summary This article reviews studies examining age-related GFR decline in men and women from the general population. The conflicting findings on sex differences in GFR decline are likely influenced by variations in study populations, including differences in comorbidities, as well as the methods used to assess GFR. Further research is essential to accurately address trajectories of GFR decline in men and women. Key Messages •Sex and gender differences in GFR levels and age-related GFR decline rates may influence the observed differences in CKD prevalence between men and women. •Possible differences in age-related GFR decline between men and women may stem from a combination of biological factors, including sex hormones, different methods to assess GFR, and differences in the prevalence and impact of risk factors. •Current eGFR equations may not accurately capture sex differences in measured GFR decline. Further research is needed to better understand these differences and their clinical implications.