Relationships of surrogate indexes of insulin resistance with insulin sensitivity assessed by euglycemic hyperinsulinemic clamp and subclinical vascular damage

IntroductionInsulin resistance plays a crucial role in the pathogenesis of type 2 diabetes and cardiovascular disease. The triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, visceral adiposity index (VAI), lipid accumulation product (LAP) and triglycerides × fasting glucose (TyG) index are surrogate measures of insulin sensitivity based on anthropometric and/or biochemical parameters routinely collected in clinical practice. Herein, we compared the relationships of these four surrogate indexes with insulin sensitivity assessed by the gold standard euglycemic hyperinsulinemic clamp technique, and subclinical vascular damage.Research design and methods631 subjects with different degrees of glucose tolerance underwent euglycemic hyperinsulinemic clamp. The surrogate TG/HDL-C ratio, VAI, LAP and TyG indexes were computed. Pulse pressure and carotid intima-media thickness (IMT) were measured as indicators of subclinical vascular damage.ResultsAll the four surrogate indexes showed a significant correlation with insulin-stimulated glucose disposal in the whole study population. However, only LAP index had a significant association with insulin sensitivity across the different glucose tolerance groups. LAP index showed the highest area under the receiver operating characteristic curve (0.728) to detect individuals with insulin resistance defined as the bottom quartile of insulin-stimulated glucose disposal, followed by TG/HDL-C ratio (0.693), TyG index (0.688) and VAI (0.688). A significant association was found between the four indexes of insulin sensitivity and pulse pressure and IMT. All the four indexes have a similar ability to detect individuals with vascular atherosclerosis defined by IMT>0.9 mm. Conversely, LAP index had the greatest ability to recognize individuals with increased vascular stiffness defined by pulse pressure ≥60 mm Hg.ConclusionAmong the surrogate TG/HDL-C ratio, VAI, LAP and TyG indexes of insulin sensitivity, LAP index showed a significant association with insulin-stimulated glucose disposal across the different glucose tolerance categories and the highest ability to detect insulin resistance and subclinical vascular damage.

Cerebral Small Vessel Disease Associated with Subclinical Vascular Damage Indicators in Asymptomatic Hypertensive Patients

Background: Cerebral small vessel disease (CSVD) is frequent in patients with cardiovascular risk factors including arterial hypertension, and it is associated with vascular damage in other organs and the risk of stroke, cognitive impairment, and dementia. Early diagnosis of CSVD could prevent deleterious consequences. Objective: To characterize CSVD associated with indicators of subclinical vascular damage in asymptomatic hypertensive patients. Materials and Methods: Participants were hypertensive (HT) and non-hypertensive (non-HT) individuals; without signs of cerebrovascular disease, dementia, and chronic renal failure. For CSVD, white matter hyperintensities (WMH), enlarged Virchow–Robin perivascular spaces (EVRPS), lacunar infarcts, and microbleeds were investigated. Subclinical vascular damage was evaluated (hypertensive retinopathy, microalbuminuria, and extracranial carotid morphology: intima media thickness (IMT) and atheroma plaque). Results: CSVD MRI findings were more frequent in HT; as well as greater intimal thickening. The IMT + plaque was significantly associated with all MRI variables; but retinopathy was correlated with EVRPS and lacunar infarcts. Only microalbuminuria was related to the greater severity of WMH in HT. Multivariate analysis evidenced that CSVD was independently associated with the combination of indicators of vascular damage and systolic blood pressure. Conclusions: Combining indicators of subclinical vascular damage, such as carotid morphological variables, microalbuminuria, and hypertensive retinopathy for early detection of CSVD in asymptomatic hypertensive patients could prove to be useful to take actions for the prevention of irreversible brain damage, which could lead to cognitive impairment, dementia and stroke.