Exploring the link between selective glomerular filtration and intima media thickness

Early kidney function decline may be associated with reduced filtration of middle-sized molecules, currently defined as selective glomerular hypofiltration syndrome (SGHS), and driven by the accumulation of atherosclerosis-promoting proteins. We aimed to investigate whether SGHS and other markers of kidney function are associated with subclinical atherosclerosis as evaluated by intima-media thickness (IMT) in the carotid arteries, and whether these associations differ by sex. Data from 2,902 individuals in the 'Malmö Diet Cancer Study', with a mean age of 56 years ± 6, none of whom had a prior diagnosis of cardiovascular disease or diabetes, were followed for 17 years (IQR 2). Kidney function was estimated using glomerular filtration equations based on cystatin C and creatinine (eGFRcys and eGFRcr). The ratio eGFRcys/eGFRcr was used to assess glomerular filtration capacity and eGFR slopes were calculated. Two indices of atherosclerosis were utilized: (1) IMT of <i>a. carotis communis</i> (IMT_CCA), (2) IMT of the far wall of the carotid bulb, both at baseline and follow-up (IMT_BULB). In women, the eGFRcys/eGFRcr ratio was associated with the annual progression of IMT_BULB. Additionally, the eGFRcys/eGFRcys ratio was associated with IMT_BULB values greater than 1.5 mm at follow-up. In men, only eGFRcys slope was predictive of being in the sex-specific 75^th percentile of IMT_CCA at follow-up; no such association was found in women. Overall, SGHS was associated with the progression of IMT_BULB, plaque presence, and greater IMT thickness at follow-up in women. In men, only a faster decline in eGFRcys was associated with plaque presence (IMT_BULB above 1.5 mm), independent of traditional cardiovascular risk factors.