Geriatric nutritional risk index is correlated with islet function but not insulin resistance in elderly patients with type 2 diabetes: A retrospective study

The geriatric nutritional risk index (GNRI) is a simple nutritional assessment tool that can predict poor prognosis in elderly subjects. The aim of this study was to evaluate the association between GNRI and both islet function and insulin sensitivity in patients with type 2 diabetes mellitus. This research carries significant implications for the integrated treatment and nutritional management of this patient population. A total of 173 patients with type 2 diabetes mellitus, aged 60 years or older, who were hospitalized in the Endocrinology Department at Hebei General Hospital from February 2018 to June 2021, were selected as the research subjects. These subjects were divided into 4 groups according to the quartile of their GNRI values: T1 (GNRI < 99.4, n = 43), T2 (99.4 ≤ GNRI < 103, n = 43), T3 (103 ≤ GNRI < 106.3, n = 43), and T4 (GNRI ≥ 106.3, n = 44). Glucose, insulin, and C-peptide concentrations were tested at 0, 30, 60, 120, and 180 minutes during a 75 g oral glucose tolerance test. The homeostasis model assessment for insulin resistance and the homeostasis model assessment for β cell function index were calculated. As the GNRI value increased, the levels of total protein, albumin, hemoglobin, alanine transaminase, aspartate aminotransferase, and 25-hydroxyvitamin D increased significantly. The area under the curve for blood glucose decreased significantly across the 4 groups, while the AUCs for insulin and C-peptide showed an overall increasing trend. β Cell function index increased significantly with the increase of GNRI; meanwhile, both the early-phase insulin secretion index and the late-phase insulin secretion index increased significantly. Although there was an increasing trend, homeostasis model assessment for insulin resistance did not change significantly among the 4 groups. This study indicates that elderly type 2 diabetes patients with higher nutritional risk have worse islet function, while insulin sensitivity is not associated with nutritional risk.

Association of Early Pregnancy Values of Glycosylated Hemoglobin and the Development of Gestational Diabetes Mellitus

Introduction There is no consensus regarding screening and diagnostic methods for gestational diabetes mellitus (GDM). The present study aimed to evaluate the association between early pregnancy values of glycosylated hemoglobin and the development of gestational diabetes mellitus among pregnant women in a tertiary care hospital in eastern India. Methods The prospective cohort study included 200 pregnant women aged between 18 and 35 years in their first trimester (gestational age eight to 13 weeks) attending the antenatal clinics of the study hospital. A glycated hemoglobin (HbA1c) test and a 75-g oral glucose tolerance test (OGTT) test were done in all study participants in their first trimester. Pregnant women with HbA1c ≥6.5% and OGTT ≥140 mg/dl were excluded from the study. In other women, the second trimester (24-28 weeks) and the third trimester OGTT (32-34 weeks) were done to detect gestational diabetes mellitus. Data collection was initiated after the approval of the Information, Education, and Communication (IEC) and relevant authorities. Receiver operating characteristic (ROC) analysis was done to identify the cut-off value of HbA1c that predicted the development of GDM. Results The incidence of GDM was 33% among our study participants. The mean HbA1c was significantly higher among women who had GDM (5.4 ± 0.4%) as compared to those who did not develop GDM (4.9 ± 0.2%) (p<0.001). On ROC analysis of HbA1c values to predict the development of GDM, a cut-off value of HbA1c ≥5.25%, irrespective of risk status, was calculated to have 84.8% sensitivity and 62.7% specificity, and among the high-risk group, HbA1c ≥5.15% had 83.3% sensitivity and 97% specificity in predicting GDM. On stratified analysis, a moderately strong positive correlation was demonstrated between HbA1c values and OGTT in the second trimester in both high-risk and low-risk cohorts (p<0.05). Conclusion Based on the findings of the present study, HbA1c can be proposed to be a suitable biomarker for GDM prediction, probably not independently but rather as a component of a multi-marker approach for high- and low-risk pregnant groups.

The Effects of Elexacaftor, Tezacaftor, and Ivacaftor (ETI) on Blood Glucose in Patients With Cystic Fibrosis: A Systematic Review

Cystic fibrosis (CF) is an autosomal recessive genetic disorder resulting from defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which in turn results in a multi-systemic disorder. There are numerous known CF alleles associated with different mutations of the CFTR gene, with the most common CF allele being a three-base-pair deletion known as ΔF508. One common manifestation of CF is glycemic dysregulation associated with decreased insulin secretion, often progressing into a distinct form of diabetes known as cystic fibrosis-related diabetes (CFRD). In the past decade, a class of drugs known as CFTR modulators has entered clinical practice. These drugs interact with the CFTR protein to restore its function, with different modulators (or combinations of modulators) suitable for patients with different CFTR mutations. Previous research has established that the modulator ivacaftor is effective in decreasing blood glucose and sometimes resolving CFRD in patients with certain CFTR mutations (class III mutations). However, early modulator therapies for individuals with the common ΔF508 mutation (e.g., a combination of the modulators lumacaftor and ivacaftor) have largely proven ineffective in improving glucose regulation. More recently, a combination therapy of three modulators, namely elexacaftor, tezacaftor, and ivacaftor (ETI), has entered clinical practice for patients with the ΔF508 mutation. However, it is not clear whether this therapy is effective in treating dysglycemia. We searched for studies of any design that examined the effects of ETI on measures of blood glucose. All available studies were observational studies comparing patients before and after initiating ETI therapy. Measures of daily-life blood glucose (those obtained with continuous glucose monitoring systems or by measuring glycated hemoglobin (HbA1c)) and post-prandial glucose spikes from oral glucose tolerance tests showed significant improvements in at least some studies. The majority of studies showed significant improvements from pre- to post-ETI in one or more blood glucose measures. While the interpretation of this evidence is complicated by the lack of randomized controlled trials, it appears that ETI therapy is associated with improved glucose regulation for at least some patients with the ΔF508 mutation.

Leg Fidgeting During Prolonged Sitting Improves Postprandial Glycemic Control in People with Obesity

OBJECTIVE

Studies have shown that fidgeting augments metabolic demand and increases blood flow to the moving limbs, whereas prolonged sitting suppresses these factors and exacerbates postprandial glucose excursions. Therefore, the hypothesis of this study was that leg fidgeting during prolonged sitting would improve postprandial glycemic control.

METHODS

Adults with obesity (n = 20) participated in a randomized crossover trial in which blood glucose and insulin concentrations were measured during a 3-hour sitting period following the ingestion of a glucose load (75 g). During sitting, participants either remained stationary or intermittently fidgeted both legs (2.5 minutes off and 2.5 minutes on). Accelerometer counts, oxygen consumption, and popliteal-artery blood flow were also measured during the sitting period.

RESULTS

As expected, fidgeting increased accelerometer counts (P < 0.01), oxygen consumption (P < 0.01), and blood flow through the popliteal artery (P < 0.05). Notably, fidgeting lowered both glucose (P < 0.01) and insulin (P < 0.05) total area under the curve (AUC) and glucose incremental AUC (P < 0.05). Additionally, there was a strong negative correlation between fidgeting-induced increases in blood flow and reduced postprandial glucose AUC within the first hour (r = -0.569, P < 0.01).

CONCLUSIONS

Leg fidgeting is a simple, light-intensity physical activity that enhances limb blood flow and can be incorporated during prolonged sitting to improve postprandial glycemic control in people with obesity.

Acipimox Acutely Increases GLP-1 Concentrations in Overweight Subjects and Hypopituitary Patients

CONTEXT

Glucagon-like peptide-1 (GLP-1) is an incretin hormone used therapeutically in type 2 diabetes and obesity. The interplay between ambient free fatty acids (FFAs) and GLP-1 remains unclear. Acipimox suppresses adipose tissue lipolysis via activation of the PUMA-G (also known as HCA2 and GPR109a) receptor.

OBJECTIVE

To investigate whether lowering of serum FFA level with acipimox affects GLP-1 secretion.

DESIGN

Two randomized crossover studies were performed in human subjects. Rat intestine was perfused intra-arterially and intraluminally, and l-cells were incubated with acipimox.

PARTICIPANTS

The participants were healthy overweight subjects and hypopituitary adult patients.

INTERVENTIONS

The overweight participants received acipimox 250 mg 60 minutes before an oral glucose test. The hypopituitary patients received acipimox 250 mg 12, 9, and 2 hours before and during the metabolic study day, when they were studied in the basal state and during a hyperinsulinemic euglycemic clamp.

RESULTS

Acipimox suppressed FFA but did not affect insulin in the clinical trials. In overweight subjects, the GLP-1 increase after the oral glucose tolerance test (area under the curve) was more than doubled [4119 ± 607 pmol/L × min (Acipimox) vs 1973 ± 375 pmol/L × min (control), P = 0.004]. In hypopituitary patients, acipimox improved insulin sensitivity (4.7 ± 0.8 mg glucose/kg/min (Acipimox) vs 3.1 ± 0.5 mg glucose/kg/min (control), P = 0.005], and GLP-1 concentrations increased ~40%. An inverse correlation between FFA and GLP-1 concentrations existed in both trials. In rat intestine, acipimox did not affect GLP-1 secretion, and l-cells did not consistently express the putative receptor for acipimox.

CONCLUSIONS

Acipimox treatment increases systemic GLP-1 levels in both obese subjects and hypopituitary patients. Our in vitro data indicate that the underlying mechanisms are indirect.

Discovery of MK-8282 as a Potent G-Protein-Coupled Receptor 119 Agonist for the Treatment of Type 2 Diabetes

The ever-growing prevalence of type 2 diabetes in the world has necessitated an urgent need for multiple orally effective agents that can regulate glucose homeostasis with a concurrent reduction in body weight. G-Protein coupled receptor 119 (GPR119) is a GPCR target at which agonists have demonstrated glucose-dependent insulin secretion and shows beneficial effects on glycemic control. Herein, we describe our efforts leading to the identification of a potent, oral GPR-119 agonist, MK-8282, which shows improved glucose tolerance in multiple animal models and has excellent off-target profile. The key design elements in the compounds involved a combination of a fluoro-pyrimidine and a conformationally constrained bridged piperidine to impart good potency and efficacy.

The SNARE Protein Syntaxin-1a Plays an Essential Role in Biphasic Exocytosis of the Incretin Hormone Glucagon-Like Peptide 1

Exocytosis of the hormone glucagon-like peptide 1 (GLP-1) by the intestinal L cell is essential for the incretin effect after nutrient ingestion and is critical for the actions of dipeptidyl peptidase 4 inhibitors that enhance GLP-1 levels in patients with type 2 diabetes. Two-photon microscopy revealed that exocytosis of GLP-1 is biphasic, with a first peak at 1-6 min and a second peak at 7-12 min after stimulation with forskolin. Approximately 75% of the exocytotic events were represented by compound granule fusion, and the remainder were accounted for by full fusion of single granules under basal and stimulated conditions. The core SNARE protein syntaxin-1a (syn1a) was expressed by murine ileal L cells. At the single L-cell level, first-phase forskolin-induced exocytosis was reduced to basal (P < 0.05) and second-phase exocytosis abolished (P < 0.05) by syn1a knockout. L cells from intestinal-epithelial syn1a-deficient mice demonstrated a 63% reduction in forskolin-induced GLP-1 release in vitro (P < 0.001) and a 23% reduction in oral glucose-stimulated GLP-1 secretion (P < 0.05) in association with impairments in glucose-stimulated insulin release (by 60%; P < 0.01) and glucose tolerance (by 20%; P < 0.01). The findings identify an exquisite mechanism of metered secretory output that precisely regulates release of the incretin hormone GLP-1 and hence insulin secretion after a meal.

Pretreatment glucose status determines HCC development in HCV patients with mild liver disease after curative antiviral therapy

Although diabetes mellitus (DM) is known to increase the risk of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC), the impact of dynamic glucose status on HCC occurrence in chronic hepatitis C (CHC) patients receiving antiviral therapy is unclear. In total, 1112 biopsy-proven patients treated with peginterferon/ribavirin were enrolled in this study. Both pretreatment and post-treatment glucose status, including 75 g oral glucose tolerance test (OGTT), were measured to evaluate the association between glucose status and the development of HCC. Of the 1112 patients evaluated, 93 (8.4%) developed HCC >5183.8 person-years of follow-up (annual incidence rate: 1.79%). DM only influenced the risk of developing CC in patients with mild liver disease (F0-2) and a sustained virological response (SVR) but not in other patient subpopulations. Cox-regression analysis demonstrated that the strongest factor associated with HCC in patients with mild liver disease and SVR was the presence of DM (hazard ratio [HR]/95 % confidence intervals [CI]: 3.79/1.420-10.136, P = 0.008), followed by age (HR/CI: 1.06/1.001-1.117, P = 0.046) and platelet count (HR/CI: 0.989/0.979-1.000, P = 0.05). The percentages of SVR patients with F0-2 with normoglycemia, pre-DM, sub-DM (pre-sDM), and DM before treatment were 45.3% (n = 267), 29.9% (n = 176), 15.6% (n = 92), and 9.2% (n = 54), respectively. The percentages of HCC in patients with normoglycemia, pre-sDM, and DM were 1.1%, 3.7%, and 11.1%, respectively (trend P < 0.001). Sixteen of the 19 (84.2 %) HCC patients possessed glucose abnormality (including 6 patients with DM and 10 patients with pre-sDM) before antiviral therapy. Compared to patients with normoglycemia, the incidence of HCC increased gradually from pre-sDM (HR: 3.6, P = 0.05) to DM (HR: 11.6, P = 0.001) (adjusted trend P = 0.004). We concluded that DM is a critical determinant for the development of HCC in SVR patients with mild liver disease. Pre-sDM status carried an additional risk for HCC, and these patients should also be carefully monitored for HCC after viral eradication.

Prevalence of gestational diabetes mellitus & associated risk factors at a tertiary care hospital in Haryana

BACKGROUND & OBJECTIVES

Prevalence of gestational diabetes mellitus (GDM) is known to vary widely depending on the region of the country, dietary habits, and socio-economic status. This study was undertaken to determine the prevalence of GDM and risk factors associated with it, in women attending an antenatal care (ANC) clinic at a tertiary care hospital in Haryana.

METHODS

This study enrolled women, with their estimated gestational age between 24th and 28th week, attending antenatal care (ANC) clinic at a tertiary care hospital in Rohtak. After informing, women who consented to participate were given a standardized 2-h 75 g oral glucose tolerance test (OGTT). A proforma containing general information on demographic characteristics, socio-economic status, education level, parity, family history of diabetes and/or hypertension and past history of GDM was filled up. American Diabetes Association (ADA) criteria for 75 g 2-h OGTT was used for diagnosing GDM.

RESULTS

A total of 607 women participated in the study and GDM was diagnosed in 43 (7.1%) women. A single abnormal value was observed in additional 66 (10.87%) women. On bivariate analysis risk factors found to be significantly associated with GDM were age, educational level, socio-economic status, pre-pregnancy weight and BMI, weight gain, acanthosis nigricans, family history of diabetes or hypertension and past history of GDM but on multivariate analysis only upper middle class and presence of acanthosis nigricans were found to be significantly associated with GDM.

INTERPRETATION & CONCLUSIONS

The prevalence of GDM was found to be 7.1 per cent in a tertiary care hospital in Haryana. Appropriate interventions are required for control and risk factor modifications.

Screening South Asians for type 2 diabetes and prediabetes: (1) comparing oral glucose tolerance and haemoglobin A1c test results and (2) comparing the two sets of metabolic profiles of individuals diagnosed with these two tests

BACKGROUND

The glycated haemoglobin A1c (HbA1c) level may be used for screening for type 2 diabetes and prediabetes instead of a more burdensome oral glucose tolerance test (OGTT). However, among the high-risk South Asian population, little is known about the overlap of the methods or about the metabolic profiles of those disconcordantly diagnosed.

METHODS

We included 944 South Asians (18-60 years old), whom we screened with the HbA1c level and the OGTT in The Hague, the Netherlands. We calculated the area under the receiver-operator characteristic curve (AUROC) with a 95% confidence interval of HbA1c using the American Diabetes Association classifications, and determined the sensitivity and specificity with 95% confidence intervals at different thresholds. Moreover, we studied differences in metabolic characteristics between those identified by HbA1c and by the OGTT alone.

RESULTS

The overlap between HbA1c and OGTT classifications was partial, both for diabetes and prediabetes. The AUROC of HbA1c for OGTT defined diabetes was 0.86 (0.79-0.93). The sensitivity was 0.46 (0.29-0.63); the specificity 0.98 (0.98-0.99). For prediabetes, the AUROC was 0.73 (0.69-0.77). Each of the 31 individuals with diabetes and 353 with prediabetes identified with the HbA1c level had a high body mass index, large waist circumference, high blood pressure, and low insulin sensitivity, all of which were similar to the values shown by those among the 19 with diabetes or 62 with prediabetes who only met the OGTT criteria, but not the HbA1c criteria.

CONCLUSIONS

The HbA1c level identified a partially different group than the OGTT did. However, both those identified with the HbA1c level and those identified with the OGTT alone were at increased metabolic risk.

TRIAL REGISTRATION

Dutch Trial Register: NTR1499.

Polycystic ovary syndrome in adolescence: impaired glucose tolerance occurs across the spectrum of BMI

CONTEXT

Polycystic ovary syndrome (PCOS) is a chronic condition with metabolic manifestations spanning the reproductive years.

OBJECTIVE

We sought to examine glucose metabolism, irrespective of the presence of obesity in a cohort of adolescent girls with PCOS.

DESIGN

One hundred adolescents were assessed for PCOS in a multi-specialty adolescent PCOS program. PCOS was diagnosed by Androgen Excess Society criteria. Oral glucose tolerance testing (OGTT), homeostatic model assessment of insulin resistance, and androgen and lipid profiles were performed for those meeting criteria.

RESULTS

Sixty-six adolescents (mean age 15.8 ± 0.2 yrs, range 13.0-18.6) had confirmed PCOS, and were eligible for inclusion in our analysis. Abnormal glucose metabolism was present in 12 of 66 (18.2%) subjects: 2 (3.0%) impaired fasting glucose, 10 (15.2%) impaired glucose tolerance (IGT), and 1 (1.5%) type 2 diabetes. IGT was the most common abnormality, occurring with equal frequency in obese (OB, mean body mass index (BMI) 36.9 ± 0.8 kg/m(2) ) and non-obese (NOB, mean BMI 24.5 ± 0.6 kg/m(2) ) adolescents (p = 0.3). In a subgroup analysis, NOB adolescents with IGT (NOB-IGT) had similar mean 2-h insulin, high density lipoprotein, C-reactive protein, and testosterone levels to the OB cohort despite marked differences in BMI (p < 0.001) and % body fat (p = 0.002). However, the NOB-IGT group had a lower mean fasting insulin level than the OB cohort (p = 0.04).

CONCLUSION

Abnormal glucose metabolism is highly prevalent in adolescents with PCOS. In particular, IGT occurs across the spectrum of BMI. A screening OGTT should be considered for adolescents diagnosed with PCOS, independently of their BMI.

Screening with OGTT alone or in combination with the Indian diabetes risk score or genotyping of TCF7L2 to detect undiagnosed type 2 diabetes in Asian Indians

BACKGROUND & OBJECTIVES

With increasing number of people with diabetes worldwide, particularly in India, it is necessary to search for low cost screening methods. We compared the effectiveness and costs of screening for undiagnosed type 2 diabetes mellitus (T2DM), using oral glucose tolerance testing (OGTT) alone, or following a positive result from the Indian Diabetes Risk Score (IDRS) or following a positive result from genotyping of the TCF7L2 polymorphisms in Asian Indians.

METHODS

In subjects without known diabetes (n=961) recruited from the Chennai Urban Rural Epidemiology Study (CURES), OGTT, IDRS, and genotyping of rs12255372 (G/T) and rs7903146(C/T) of TCF7L2 polymorphisms were done. IDRS includes four parameters: age, abdominal obesity, family history of T2DM and physical activity.

RESULTS

OGTT identified 72 subjects with newly diagnosed diabetes (NDD), according to the World Health Organization criteria of fasting plasma glucose ≥ 126 mg/dl or a plasma glucose ≥ 200 mg/dl, 2 h after 75 g oral glucose load. IDRS screening (cut-off ≥ 60) yielded 413 positive subjects, which included 54 (75%) of the 72 NDD subjects identified by OGTT. Genotyping yielded 493 positive subjects which only included 36 (50%) of the 72 NDD subjects showing less discriminatory power. Screening with both SNPs missed 27 (37.5%) NDD subjects identified by IDRS. In contrast, IDRS missed only 9 (12.5%) of the NDD subjects identified by genotyping. Total screening cost for OGTT alone, or with IDRS were rs 384,400 and 182,810 respectively. Comparing OGTT alone to IDRS followed by OGTT, the incremental cost per additional NDD subject detected by doing OGTT on everyone was rs 11,199 (rs 201,590 for detecting additional 18 NDD subjects).

INTERPRETATION & CONCLUSIONS

For screening a population of subjects without diagnosed diabetes in India, a simple diabetes risk score is more effective and less expensive than genotyping or doing OGTT on the whole population.

Prevalence of undiagnosed diabetes and quality of care in diabetic patients followed at primary and tertiary clinics in Abu Dhabi, United Arab Emirates

AIMS

To investigate the prevalence of undiagnosed type 2 diabetes (T2D) at primary health care (PHC) clinics, and to assess the quality of care of diabetic patients followed at a tertiary hospital diabetes center in Abu Dhabi, United Arab Emirates (UAE).

METHODS

Between May 2009 and October 2010, adult patients attending two PHC clinics, and adult diabetic patients attending the diabetes center, were invited to participate in the study. After overnight fast, participants returned for interview and laboratory tests. Undiagnosed T2D was defined by FPG ≥ 7.0 mmol/l or HbA1c ≥ 6.5%. Quality of care was assessed by reported care practices and achievement of internationally recognized targets.

RESULTS

Out of 239 patients at PHC clinics without history of T2D, 14.6% had undiagnosed T2D, and 31% had increased risk of diabetes (FPG 5.6-7.0 mmol/l or HbA1c 5.7-6.5%). The independent predictors of undiagnosed T2D were age (adjusted OR per year 1.07, 95% CI 1.04-1.11, p < 0.001) and BMI ≥ 25 (adjusted OR 4.2, 95% CI 0.91-19.7, p = 0.033). Amongst all 275 diagnosed T2D patients, including those attending PHC clinics and those followed at the diabetes center, it was found that 40.1% followed dietary recommendations, 12% reported visiting a diabetes educator, 28.2% walked for exercise, and 13.5% attained recognized targets of HbA1c < 7%, blood pressure < 130/80 mmHg, and LDL cholesterol < 2.6 mmol/l.

CONCLUSIONS

Almost half of the adult patients attending PHC clinics had undiagnosed T2D, or increased diabetes risk. Care practices, and achievement of treatment targets, were suboptimal.

First phase insulin release and glucose tolerance in children with Fanconi anemia after hematopoietic cell transplantation

BACKGROUND

Fanconi anemia (FA) is an autosomal and X-linked recessive disease of chromosomal instability, which results in bone marrow failure. Children with FA have been shown to have an increased risk of diabetes mellitus (DM).

PROCEDURE

A cross-sectional study of glucose and insulin metabolism was conducted in 17 children with FA who had undergone hematopoietic cell transplantation (HCT) at the University of Minnesota. First phase insulin release (FPIR) was determined by intravenous glucose tolerance test (IVGTT). Oral glucose tolerance test (OGTT), lipid panel, blood pressure, and medical history were reviewed for additional metabolic abnormalities.

RESULTS

Seventeen FA participants, median age 11.3 (range 5.5-17.6) years, were evaluated. IVGTT identified three separate groups: low FPIR, normal FPIR, and high FPIR. Those with low FPIR were more likely to have low BMI, but had normal glucose levels. Those with high FPIR, had high BMI, elevated lipids, and body fat. One patient with normal FPIR had impaired glucose tolerance and another with normal FPIR had impaired fasting glucose. No participant was diagnosed with DM by fasting glucose, 2 hr glucose during OGTT, or hemoglobin A1C.

CONCLUSIONS

The majority of children with FA had normal glucose tolerance and normal beta-cell function after HCT. Two small subsets of patients had lower than expected and higher than expected FPIR. The clinical significance of these differences is not yet known given the normal glucose tolerance and fasting glucose levels in these two groups.

Insulin resistance, secretion and breakdown are increased 9 months following severe burn injury

Insulin resistance in the acute burn period has been well described, however, it is unknown if alterations in glucose metabolism persist beyond discharge from the acute injury. To measure the duration of insulin resistance following recovery from the acute burn injury, we performed a prospective cross-sectional study with a standard 2-h oral glucose tolerance test in 46 severely burned children at 6, 9 or 12 months following initial injury. Glucose uptake and insulin secretion were assessed following the glucose load. Results were compared to those previously published in healthy children. At 6 months after burn, the 2-h glucose concentration was significantly (P<0.001) greater than controls, and the area under the curve (AUC) of glucose was significantly higher compared to 12 months and to healthy children (P=0.027 and P<0.001, respectively). The 9-month AUC glucose was higher than controls (P<0.01). The 6-month 2-h insulin was significantly higher than controls, as was the AUC of insulin in all time points post-burn. The AUC of C-peptide was significantly greater at 6 months after injury compared to 9 and 12 months (P<0.01 for both). Increased 2h and AUC glucose and insulin indicate that glucose metabolism is still affected at 6 and 9 months after injury, and coincides with previously documented defects in bone and muscle metabolism at these time points. Insulin breakdown is also still increased in this population. Further study of this population is warranted to determine if specific treatment is needed.

Measures of beta-cell function during the oral glucose tolerance test, liquid mixed-meal test, and hyperglycemic clamp test

OBJECTIVE

To evaluate clinically useful measures of beta-cell function derived from the oral glucose tolerance test (OGTT) or mixed-meal (ie, Boost) tolerance test to assess insulin secretion in comparison with the gold standard, the hyperglycemic clamp (Hyper-C) test.

STUDY DESIGN

We hypothesized that OGTT/Boost-derived measures are useful estimates of beta-cell function and correlate well with insulin secretion measured by the Hyper-C test. This study was designed to assess the correlation between the ratio of the early incremental insulin/glucose responses at 15 and 30 minutes (DeltaI(15)/DeltaG(15) and DeltaI(30)/DeltaG(30)) of the OGTT and the Boost test with insulin secretion measured during the Hyper-C test (225 mg/dL). The same indices were evaluated using C-peptide. A total of 26 children (14 males, 12 females; mean age, 9.9 +/- 0.2 years; mean body mass index = 22.1 +/- 1.2 kg/m(2)) underwent a 2-hour Hyper-C test (225 mg/dL) and 3-hour OGTT and Boost tests with measurements of glucose, insulin, and C-peptide.

RESULTS

Correlations between Hyper-C- and OGTT-derived measures of insulin secretion were stronger for the 15-minute index than for the 30-minute index of insulin secretion and stronger for C-peptide levels than for insulin levels (r = .7, P < .001 for first-phase C-peptide vs both OGTT and Boost, DeltaC(15)/DeltaG(15)).

CONCLUSIONS

In children with normal glucose tolerance, C-peptide rather than insulin level measured after 15 minutes of the OGTT or Boost test provides a reliable estimate of beta-cell function that correlates well with Hyper-C-derived insulin secretion.