Association between renal hyperfiltration, arterial stiffness and subendocardial viability ratio in prediabetic subjects: a cross-sectional study.

Background: Glomerular hyperfiltration is a well-recognized early renal alteration in subjects with diabetes mellitus and a strong and independent predictor of cardiovascular events in these patients. Prediabetes has been associated with increased glomerular filtration rate (GFR), however, the association between prediabetes, glomerular hyperfiltration and early markers of cardiovascular damage has not been investigated. The aim of this study was to investigate the association between renal hyperfiltration (RHF) and early markers of cardiovascular disease in subjects with prediabetes.Methods: Arterial stiffness [Augmentation Pressure (Aug), Augmentation Index (AugI)], subendocardial viability ratio (SEVR), pulse wave velocity (PWV), intima-media thickness (IMT), glycated hemoglobin (HbA1c), oral glucose tolerance test and estimated GFR (eGFR) were evaluated in 230 subjects with prediabetes. The eGFR was assessed using the Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI). Hyperfiltration was defined as an eGFR above the 75th percentile.The subjects were divided into two groups according to the presence or absence of RHF: 169 subjects with prediabetes without RHF and 61 subjects with prediabetes with RHF.Results: Subjects with RHF showed higher Aug, AugI and lower SEVR compared with prediabetic subjects with lower eGFR (14.1±7.2 vs 10.8±6.2, 32.9±12.7 vs 27.6±11.7, 153.5±27.8 vs 162±30.2, P<0.05). No differences were found in PWV and IMT values between the two groups. We then performed multiple regression analysis to test the relationship between Aug, SEVR and several cardiovascular risk factors. In multiple regression analysis Aug was associated with age, systolic blood pressure (SBP), homeostatic model assessment for insulin resistance (HOMA-IR) and eGFR; the major determinants of SEVR were eGFR, HOMA-IR and SBP.Conclusions: Our data show that subjects with prediabetes and RHF exhibited an increased Aug, AugI and a reduced SEVR. Longitudinal studies are needed to explore whether hyperfiltration increases the possibility of diabetic nephropathy and cardiovascular disease in individuals with prediabetes.