Myths and methodologies: Assessing glycaemic control and associated regulatory mechanisms in human physiology research.

Accurate measurements of glycaemic control and the underpinning regulatory mechanisms are vital in human physiology research. Glycaemic control is the maintenance of blood glucose concentrations within optimal levels and is governed by physiological variables including insulin sensitivity, glucose tolerance and ß-cell function. These can be measured with a plethora of methods, all with their own benefits and limitations. Deciding on the best method to use is challenging and depends on the specific research question(s). This review therefore discusses the theory and procedure, validity and reliability and any special considerations of a range common methods used to measure glycaemic control, insulin sensitivity, glucose tolerance and ß-cell function. Methods reviewed include glycosylated haemoglobin, continuous glucose monitors, the oral glucose tolerance test, mixed meal tolerance test, hyperinsulinaemic euglycaemic clamp, hyperglycaemic clamp, intravenous glucose tolerance test and indices derived from both fasting concentrations and the oral glucose tolerance test. This review aims to help direct understanding, assessment and decisions regarding which method to use based on specific physiology-related research questions.

Clinical Pharmacology of GP40321 (Insulin Glulisine Biosimilar): Pharmacokinetic and Pharmacodynamic Comparability in a Hyperinsulinemic-Euglycemic Clamp Procedure.

The aim of the study was to compare the pharmacokinetics (PK) and pharmacodynamics (PD) of T-glu (GP40321, test drug), and reference insulin glulisine in a hyperinsulinemic-euglycemic clamp procedure. During this study, 34 healthy male volunteers underwent the hyperinsulinemic-euglycemic clamp procedure following subcutaneous 0.3 U/kg injection of T-glu or reference insulin glulisine in a randomized, double-blind, crossover study. Plasma glucose levels were monitored every 5 minutes for 8 hours. Glucose infusion rate adjustment was based on the blood glucose measurements. Evaluation of PD was performed using the glucose infusion rate values, while PK was calculated using insulin concentrations measured via enzyme-linked immunosorbent assay. The study results showed that the 90% CI for the geometric mean ratios of primary PK and PD of T-glu and reference insulin glulisine were within 80%-125% comparability limits, and that the safety profiles were comparable. PK, PD, and safety similarity of T-glu and reference insulin glulisine was demonstrated.

Effect of obstructive sleep apnea on glucose metabolism.

BACKGROUND: Obstructive sleep apnea (OSA) is prevalent in people with obesity and is a major risk factor for type 2 diabetes (T2D). The effect of OSA on metabolic function and the precise mechanisms (insulin resistance, ß-cell dysfunction, or both) responsible for the increased T2D risk in people with OSA are unknown. DESIGN AND METHODS: We used a two-stage hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotopically labeled glucose and palmitate tracer infusions and 18F-fluorodeoxyglucose injection and positron emission tomography to quantify multi-organ insulin action and oral and intravenous tolerance tests to evaluate glucose-stimulated insulin secretion in fifteen people with obesity and OSA and thirteen people with obesity without OSA. RESULTS: OSA was associated with marked insulin resistance of adipose tissue triglyceride lipolysis and glucose uptake into both skeletal muscles and adipose tissue, whereas there was no significant difference between the OSA and control groups in insulin action on endogenous glucose production, basal insulin secretion, and glucose-stimulated insulin secretion during both intravenous and oral glucose tolerance tests. CONCLUSIONS: These data demonstrate that OSA is a key determinant of insulin sensitivity in people with obesity and underscore the importance of taking OSA status into account when evaluating metabolic function in people with obesity. These findings may also have important clinical implications because disease progression and the risk of diabetes-related complications vary by T2D subtype (i.e. severe insulin resistance vs insulin deficiency). People with OSA may benefit most from the targeted treatment of peripheral insulin resistance and early screening for complications associated with peripheral insulin resistance.

Similar pharmacokinetics and pharmacodynamics of a new biosimilar and reference insulin aspart in healthy Chinese males.

Insulin aspart (IAsp) is one of the main therapies used to control blood glucose after a meal. This study aimed to compare the pharmacokinetics (PK) and pharmacodynamics (PD) of 2 rapid-acting IAsp products: a new IAsp biosimilar (RD10046) and NovoRapid. In a single-center, randomized, single-dose, 2-period, crossover, euglycemic clamp study (registry number: CTR20180517, registration date: 2018-05-30), healthy Chinese males were randomized to receive 0.2 U/kg of the IAsp biosimilar RD10046 and NovoRapid under fasted conditions on two separate occasions. PK and PD were assessed for up to 10 h. Of the 30 randomized subjects, all 30 completed both treatment periods. The PK (area under the curve [AUC] of total IAsp; maximum observed IAsp concentration [Cmax]) and PD (maximum glucose infusion rate [GIRmax]; total glucose infusion during the clamp [AUCGIR,0-10h]) were similar between the new IAsp biosimilar RD10046 and NovoRapid. In all cases, the 90% CIs for the ratios of the geometric means were completely contained in the prespecified acceptance limits of 0.80-1.25. No hypoglycemic events, allergic reactions, or local injection adverse reactions occurred in this trial. We concluded that the studied IAsp biosimilar (RD10046) was bioequivalent to NovoRapid.

Precision and accuracy of hyperglycemic clamps in a multicenter study.

Application of glucose clamp methodologies in multicenter studies brings challenges for standardization. The Restoring Insulin Secretion (RISE) Consortium implemented a hyperglycemic clamp protocol across seven centers using a combination of technical and management approaches to achieve standardization. Two-stage hyperglycemic clamps with glucose targets of 200 mg/dL and >450 mg/dL were performed utilizing a centralized spreadsheet-based algorithm that guided dextrose infusion rates using bedside plasma glucose measurements. Clamp operators received initial and repeated training with ongoing feedback based on surveillance of clamp performance. The precision and accuracy of the achieved stage-specific glucose targets were evaluated, including differences by study center. We also evaluated robustness of the method to baseline physiologic differences and on-study treatment effects. The RISE approach produced high overall precision (3%-9% variance in achieved plasma glucose from target at various times across the procedure) and accuracy (SD < 10% overall). Statistically significant but numerically small differences in achieved target glucose concentrations were observed across study centers, within the magnitude of the observed technical variability. Variation of the achieved target glucose over time in placebo-treated individuals was low (<3% variation), and the method was robust to differences in baseline physiology (youth vs. adult, IGT vs. diabetes status) and differences in physiology induced by study treatments. The RISE approach to standardization of the hyperglycemic clamp methodology across multiple study centers produced technically excellent standardization of achieved glucose concentrations. This approach provides a reliable method for implementing glucose clamp methodology across multiple study centers.NEW & NOTEWORTHY The Restoring Insulin Secretion (RISE) study centers undertook hyperglycemic clamps using a simplified methodology and a decision guidance algorithm implemented in an easy-to-use spreadsheet. This approach, combined with active management including ongoing central data surveillance and routine feedback to study centers, produced technically excellent standardization of achieved glucose concentrations on repeat studies within and across study centers.

Targeted lipidomics reveals associations between serum sphingolipids and insulin sensitivity measured by the hyperinsulinemic-euglycemic clamp.

AIMS: Sphingolipids(SPs) and their substrates and constituents, fatty acids (FAs), are implicated in the pathogenesis of various metabolic diseases associated. This study aimed to systematically investigate the associations between serum sphingolipids and insulin sensitivity as well as insulin secretion. METHODS: We conducted a lipidomics evaluation of molecularly distinct SPs in the serum of 86 consecutive Chinese adults using LC/MS. The glucose infusion rate over 30 min (GIR30) was measured under steady conditions to assess insulin sensitivity by the gold standard hyperinsulinemic-euglycemic clamp. We created the ROC curves to detect the serum SMs diagnostic value. RESULTS: Total and subspecies of serum SMs and globotriaosyl ceramides (Gb3s) were positively related to GIR30, free FAs (FFA 16:1, FFA20:4), some long chain GM3 and complex ceramide GluCers showed strong negative correlations with GIR30. Notably, ROC curves showed that SM/Cer and SM d18:0/26:0 may be good serum lipid predictors of diagnostic indicators of insulin sensitivity close to conventional clinical indexes such as 1/HOMA-IR (areas under the curve > 0.80) based on GIR30 as standard diagnostic criteria, and (SM/Cer)/(BMI*LDLc) areas under the curve = 0.93) is the best. CONCLUSIONS: These results provide novel associations between serum sphingolipid between insulin sensitivity measured by the hyperinsulinemic-euglycemic clamp and identify two specific SPs that may represent prognostic biomarkers for insulin sensitivity.

The metabolic footprint of compromised insulin sensitivity under fasting and hyperinsulinemic-euglycemic clamp conditions in an Arab population.

Metabolic pathways that are corrupted at early stages of insulin resistance (IR) remain elusive. This study investigates changes in body metabolism in clinically healthy and otherwise asymptomatic subjects that may become apparent already under compromised insulin sensitivity (IS) and prior to IR. 47 clinically healthy Arab male subjects with a broad range of IS, determined by hyperinsulinemic-euglycemic clamp (HIEC), were investigated. Untargeted metabolomics and complex lipidomics were conducted on serum samples collected under fasting and HIEC conditions. Linear models were used to identify associations between metabolites concentrations and IS levels. Among 1896 identified metabolites, 551 showed significant differences between fasting and HIEC, reflecting the metabolic switch in energy utilization. At fasting, 336 metabolites, predominantly di- and tri-acylglycerols, showed significant differences between subjects with low and high levels of IS. Changes in amino acid, carbohydrate and fatty acid metabolism in response to insulin were impaired in subjects with low IS. Association of altered mannose and amino acids with IS was also replicated in an independent cohort of T2D patients. We identified metabolic phenotypes that characterize clinically healthy Arab subjects with low levels of IS at their fasting state. Our study is providing further insights into the metabolic pathways that precede IR.

A Human Randomized Controlled Trial Comparing Metabolic Responses to Single and Repeated Hypoglycemia in Type 1 Diabetes.

AIMS: Hypoglycemia hinders optimal glycemic management in type 1 diabetes (T1D). Long diabetes duration and hypoglycemia impair hormonal counter-regulatory responses to hypoglycemia. Our study was designed to test whether (1) the metabolic responses and insulin sensitivity are impaired, and (2) whether they are affected by short-lived antecedent hypoglycemia in participants with T1D. MATERIALS AND METHODS: In a randomized, crossover, 2x2 factorial design, 9 male participants with T1D and 9 comparable control participants underwent 30 minutes of hypoglycemia (p-glucose < 2.9 mmol/L) followed by a euglycemic clamp on 2 separate interventions: with and without 30 minutes of hypoglycemia the day before the study day. RESULTS: During both interventions insulin sensitivity was consistently lower, while counter-regulatory hormones were reduced, with 75% lower glucagon and 50% lower epinephrine during hypoglycemia in participants with T1D, who also displayed 40% lower lactate and 5- to 10-fold increased ketone body concentrations following hypoglycemia, whereas palmitate and glucose turnover, forearm glucose uptake, and substrate oxidation did not differ between the groups. In participants with T1D, adipose tissue phosphatase and tensin homolog (PTEN) content, hormone-sensitive lipase (HSL) phosphorylation, and muscle glucose transporter type 4 (GLUT4) content were decreased compared with controls. And antecedent hypoglycemic episodes lasting 30 minutes did not affect counter-regulation or insulin sensitivity. CONCLUSIONS: Participants with T1D displayed insulin resistance and impaired hormonal counter-regulation during hypoglycemia, whereas glucose and fatty acid fluxes were intact and ketogenic responses were amplified. We observed subtle alterations of intracellular signaling and no effect of short-lived antecedent hypoglycemia on subsequent counter-regulation. This plausibly reflects the presence of insulin resistance and implies that T1D is a condition with defective hormonal but preserved metabolic responsiveness to short-lived hypoglycemia.

Estimated insulin sensitivity in Type 1 diabetes adults using clinical and research biomarkers.

AIMS: Insulin resistance in people with type 1 diabetes (T1D) is associated with increased risk of chronic complications and death. The gold standard to quantify insulin sensitivity, a euglycaemic hyperinsulinaemic clamp, is not applicable to clinical practice. We have employed clamp studies to develop a panel of formulae to estimate insulin sensitivity in adults with T1D for use in clinical practice and trials. METHODS: Clamps were conducted in 28 adults with T1D, who were also characterised with 38 clinical and research biomarkers. Exhaustive search analysis was used to derive equations correlating with clamp-quantified glucose disposal rate (GDR), GDR/plasma insulin (M/I) and log10M/I. RESULTS: Measured insulin sensitivity correlated with BMI, WHR, HDL-C, adipokines and inflammation markers on univariate analysis. Exhaustive search analysis derived three formulae correlating with clamp-derived GDR and logM/I (p < 0.0001), accounting for ≈62% of their variability. A formula using gender, age, HDL-C, pulse pressure and WHR performed as well as those containing inflammation and adipokine measures. CONCLUSIONS: The performance of formulae using routinely available parameters with/without research biomarkers in clinical studies and trials, particularly related to future complications, relevant lifestyle interventions, insulin delivery modes and insulin sensitisers is merited.

Effect of insulin on natriuretic peptide gene expression in porcine heart.

Gut hormones affect cardiac function and contractility. In this study, we examined whether insulin affects the cardiac atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) gene expression and release of proANP-derived peptides in pigs. Anaesthetized pigs were included in an experimental study comparing the effect of hyperinsulinemia in 15 pigs submitted to two different protocols versus 11 control pigs receiving saline infusion. Phosphorylation of Akt on Thr308 was determined by western blotting with a pAkt-Thr308 antibody. The mRNA contents of ANP and BNP were determined with real-time PCR; plasma and cardiac tissue proANP was measured with an immunoluminometric assay targeted against the mid-region of the propeptide and a processing-independent assay. Insulin stimulation increased phosphorylation of Akt Thr308 in both left atrium and left ventricle of porcine hearts (p < 0.005). No change was observed in ANP and BNP mRNA contents in the right or left atrium. BNP mRNA contents in the left ventricle, however, decreased 3-fold (p = 0.02) compared to control animals, whereas the BNP mRNA content in the right ventricle as well as ANP mRNA content in the right and left ventricle did not change following hyperinsulinemia. Moreover, the peptide contents did not change in the four cardiac chambers. Finally, proANP concentrations in plasma did not change during the insulin infusion compared to the control animals. These results suggest that insulin does not have direct effect on atrial natriuretic peptide expression but may have a role in the left ventricle.

Direct Relationship Between Metabolic Flexibility Measured During Glucose Clamp and Prolonged Fast in Men.

OBJECTIVE: This study aimed to determine the relationship between metabolic flexibility (MetFlex) measured during a euglycemic-hyperinsulinemic clamp and a prolonged fast. This study also analyzed the association between MetFlex and metabolic health. METHODS: Eighteen healthy men (mean [SD]: 22 [2] years old; BMI: 22 [1] kg/m2 ) performed two sessions: (1) euglycemic-hyperinsulinemic clamp (2 mIU/kg of insulin per minute) and (2) ~20-hour fast. Clamp MetFlex corresponded to the change in (Δ) respiratory quotient (RQ) (ΔRQ = postchallenge RQ - prechallenge RQ) adjusted for M value and prechallenge RQ. Prolonged fast MetFlex corresponded to the ΔRQ adjusted for the Δß-hydroxybutyrate and prechallenge RQ. RESULTS: MetFlex during the clamp related directly with MetFlex during prolonged fast (r = 0.59, P = 0.014). Using the median of MetFlex for each challenge, this study split participants into high or low MetFlex. Participants with high or low MetFlex to both challenges were identified. Participants with high MetFlex had 3% lower serum low-density lipoprotein cholesterol than participants with low MetFlex (P = 0.021). CONCLUSIONS: Measuring MetFlex during a clamp or a prolonged fast produces similar results, despite challenging the oxidation of different substrates. An impaired MetFlex in response to these challenges may be an early event in the development of abnormal lipid metabolism.

Multi-year reproducibility of hyperinsulinemic euglycemic clamp-derived insulin sensitivity in free-living adults: Association with incident prediabetes in the POP-ABC study.

OBJECTIVE: The hyperinsulinemic euglycemic clamp (HEC) is the "gold standard" for measuring insulin sensitivity (Si-clamp). Here, we determined the reproducibility of serial HEC data in healthy subjects. RESEARCH DESIGN AND METHODS: The Pathobiology of Prediabetes in A Biracial Cohort study assessed incident prediabetes in healthy African Americans (AA) and European Americans (EA) with parental type 2 diabetes mellitus during 5.5 years of follow-up. Assessments included anthropometry, OGTT, and HEC. Ninety subjects (44 AA, 46 EA) who underwent Year-1HEC consented to Year-3 HEC. We calculated coefficients of variation (CVs), 95% limits of agreement, and repeatability coefficients for Year-1 and Year-3 data, and assessed the association of change in Si-clamp with incident prediabetes. RESULTS: The mean (SD) baseline age was 47.5 ±â€¯8.13y, body mass index was 30.4 ±â€¯9.16 kg/m2, fasting plasma glucose was 93.7 ±â€¯7.82 mg/dL and 2-hrPG was 126 ±â€¯26.8 mg/dL. Si-clamp (umol/kg/min·pmol/L-1) was 0.071 ±â€¯0.04 in Year 1 and 0.067 ±â€¯0.04 in Year 3 (P = 0.22). Year 1 and Year 3 values were strongly correlated (r = 0.81, P < 0.0001); the CV was 13.6% and repeatability coefficient was ±0.025. Intrasubject differences in serial Si-clamp were less than the repeatability coefficients and within the 95% limits of agreement. After 5.5 years of follow-up, 40 subjects progressed to prediabetes and 50 were nonprogressors. The change in Si-clamp was greater in progressors than nonprogressors (-10% vs. -2.5%, P = 0.02). CONCLUSIONS: The HEC is reproducible over ~2 years in free-living individuals, with a temporal decline in Si-clamp that predicts prediabetes risk.

Substantial inter-individual variations in insulin secretion and sensitivity across the glucometabolic spectrum.

Impaired insulin secretion and action are important for development of type 2 diabetes (T2D) and metabolic syndrome (MetS). Despite recognized heterogeneity of these glucometabolic disorders, few data are available of biological variation in insulin secretion and action among individuals with T2D and MetS. The aim of this study was to explore the inter-individual variations using gold standard methods in a cross-sectional study of two independent cohorts of phenotypically well-characterized subjects. Cohort I included 486 subjects with MetS, and cohort II 62 subjects with established T2D. First phase insulin secretion was defined as the incremental area under the curve 0-8 min (iAUC0-8 min) during an intravenous glucose tolerance test (IVGTT). Insulin sensitivity was measured as the insulin sensitivity index (SI) modelled from IVGTT in cohort I, and in II as total glucose disposal (TGD) estimated from a euglycaemic-hyperinsulinaemic clamp. Variation is given as total range and, fold-variation between 5%- and 95%-percentile. The iAUC0-8 min ranged from -60 to 3397 mUL-1min-1 among subjects with MetS and from -263 to 1194 mUL-1min-1 in subjects with T2D, representing a more than 10-fold variation. Insulin sensitivity ranged from SI 0.19 to 15.29 (mU/L)-1min-1 among subjects with MetS and TGD 12.9-101.6 µmolkgFFM-1min-1 in subjects with T2D, representing a 6.8 and 5.5-fold variation, respectively. The other components of MetS; BMI, waist-hip ratio, HDL-cholesterol, triglycerides and blood pressure (BP), showed a 1.4-4.7-fold variation. In conclusion, our data demonstrated extensive inter-individual variations in insulin secretion and sensitivity. These variations may be essential to take into account when planning clinical research and treatment in subjects with T2D and MetS.

Classification before regression for improving the accuracy of glucose quantification using absorption spectroscopy.

This work contributes to the improvement of glucose quantification using near-infrared (NIR), mid-infrared (MIR), and combination of NIR and MIR absorbance spectroscopy by classifying the spectral data prior to the application of regression models. Both manual and automated classification are presented based on three homogeneous classes defined following the clinical definition of the glycaemic ranges (hypoglycaemia, euglycaemia, and hyperglycaemia). For the manual classification, partial least squares and principal component regressions are applied to each class separately and shown to lead to improved quantification results compared to when applying the same regression models for the whole dataset. For the automatic classification, linear discriminant analysis coupled with principal component analysis is deployed, and regressions are applied to each class separately. The results obtained are shown to outperform those of regressions for the entire dataset.

Hypoglycaemia leads to a delayed increase in platelet and coagulation activation markers in people with type 2 diabetes treated with metformin only: Results from a stepwise hypoglycaemic clamp study.

AIMS: To investigate the effect of hypoglycaemia on platelet and coagulation activation in people with type 2 diabetes. MATERIALS AND METHODS: This monocentric, open, single-arm, mechanistic trial included 14 people with established type 2 diabetes (four women, 10 men, age 55 ± 7 years, glycated haemoglobin concentration 51 ± 7 mmol/mol) receiving metformin monotherapy. A stepwise hyperinsulinaemic-hypoglycaemic clamp experiment (3.5 and 2.5 mmol/L, for 30 minutes respectively) was performed, aiming to investigate platelet and coagulation activity during predefined plateaus of hypoglycaemia, as well as 1 day and 7 days later. RESULTS: While platelet activation assessed by light transmittance aggregometry did not significantly increase after the hypoglycaemic clamp procedure, the more sensitive flow cytometry-based measurement of platelet surface activation markers showed hypoglycaemia-induced activation 24 hours (PAC1pos CD62Ppos , PAC1pos CD63Ppos and PAC1pos CD62Ppos CD63pos ; P < .01) and 7 days after the hypoglycaemic clamp (P < .001 for PAC1pos CD63pos ; P < .01 for PAC1pos CD62Ppos and PAC1pos CD62Ppos CD63pos ) in comparison to baseline. Coagulation markers, such as fibrinogen, D-dimer, plasminogen activator inhibitor-1, von Willebrand factor activity and factor VIII, were also significantly increased, an effect that was most pronounced 24 hours after the hypoglycaemic clamp. CONCLUSION: A single event of insulin-induced hypoglycaemia led to an increase in markers of platelet activation and coagulation in people with early stages of type 2 diabetes on metformin therapy. However, the activation occurred with a delay and was evident 24 hours and 7 days after the actual hypoglycaemic episode.

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

Introduction: Insulin 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 methods: 631 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. Results: All 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. Conclusion: Among 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.

Optimized fasting and OGTT-based simple surrogate methods for assessing insulin sensitivity.

AIMS: Simple surrogate indices of insulin sensitivity have been conceived to deal with costly and complicated approaches, such as the hyperinsulinemic-euglycemic clamp; however, their use has not been widespread given their variabilities in different populations. In this paper, we present two simple surrogate indices, one that uses fasting glucose and insulin values and the other based on the values from the oral glucose tolerance test. MATERIALS AND METHODS: The proposed methods integrate easy-to-obtain anthropometric measures. Evolutionary algorithms were used to optimize the proposed methods by maximizing its correlation with the Stumvoll MCR method. RESULTS AND CONCLUSION: When the proposed indices were applied to three study groups (control subjects, metabolic syndrome, marathon runners), a reduction in the intergroup variability of the insulin sensitivity was obtained. Moreover, the proposed index based on the oral glucose tolerance test (OGTT), which considers the glucose metabolism process and the hepatic and peripheral insulin sensitivity, showed stronger correlations with the Stumvoll method and lower intergroup variability than the fasting one.

Screening for a Simple and Effective Indicator of Insulin Resistance in Chinese Reproductive-Aged Women, with the Insulin Clamp Technique as a Reference.

Background: Applying the hyperinsulinemic-euglycemic clamp to estimate insulin resistance (IR) is accurate but time-consuming, so identifying a simple and effective index for IR is vitally important. The present study aimed to compare the lipid accumulation product (LAP), visceral adiposity index (VAI), body mass index (BMI), waist circumference (WC), homeostasis model assessment of insulin resistance (HOMA-IR), and Chinese visceral adiposity index (CVAI) using the hyperinsulinemic-euglycemic clamp as a reference and to screen a simple and effective indicator for IR in Chinese women of childbearing age. Methods: The present study included a cross-sectional study of 537 reproductive-aged women and an interventional study of 90 randomly chosen polycystic ovarian syndrome (PCOS) women. Physical, laboratory, and hyperinsulinemic-euglycemic clamp were completed, and the BMI, WC, LAP, VAI, CVAI, and HOMA-IR were calculated. A linear correlation and a receiver operating characteristic curve were performed. After intervention with metformin, the effects were estimated in the third month. Results: PCOS women had worse glycometabolism, serum lipid metabolism and IR, and higher prevalence rates of metabolic disorders than those without PCOS. The CVAI was strongly associated with the M value (r = -0.6953, P < 0.0001) and outperformed other parameters with the largest area under the curve (0.903) and Youden index (71.07%) for IR diagnosis in Chinese reproductive-aged women, and the diagnostic point was >28.5. After 3 months of metformin therapy, IR improved with remarkable increases in M value and reductions in the CVAI. Conclusion: The CVAI can be used as an appropriate surrogate indicator for the hyperinsulinemic-euglycemic clamp to identify IR in Chinese women of childbearing age. The interventional trial part of this study has been registered as a clinical trial (no. ChiCTR-IIR-16007901).