Estimation of glucose absorption, insulin sensitivity, and glucose effectiveness from the oral glucose tolerance test.

CONTEXT: Glucose tolerance during an oral glucose tolerance test (OGTT) is affected by variations in glucose effectiveness (GE) and glucose absorption and thus affects minimal model calculations of insulin sensitivity (SI). The widely used OGTT SI by Dalla Man et al. does not account for variances in GE and glucose absorption. OBJECTIVE: To develop a novel model that concurrently assesses SI, GE, and glucose absorption. DESIGN: Cross-sectional. SETTING: Academic Medical Center. PARTICIPANTS: Eighteen subjects without abnormalities on OGTT (controls) and 88 subjects with diabetes. INTERVENTION: All subjects underwent 75-gram 120-minute 6-timepoint OGTT. MAIN OUTCOMES: SI from the Dalla Man model was validated with the novel model Si using Bland Altman limits of agreement methodology. Comparisons of SI, GE, and gastrointestinal glucose half-life (GIGt1/2); a surrogate measure for glucose absorption were made between subjects with diabetes and controls. RESULTS: In controls and diabetes, the novel model SI was higher than the current OGTT model. SI from both controls (ƿ=0.90, p < 0.001) and diabetes (ƿ=0.77, p < 0.001) has high agreement between models. GE was higher in diabetes (median:0.021 1/min, IQR [interquartile range]: 0.020-0.022) compared to controls (median:0.016 1/min, IQR: 0.015-0.017), p = 0.02. GIGt1/2 was shorter in diabetes (median: 48.404 min, IQR: 54.424-39.426) than in controls (median: 55.086 min, IQR: 61.368-48.502) without statistical difference. CONCLUSIONS: Our novel model SI has a good correlation with SI from the widely used Dalla Man's model while concurrently calculating GE and GIGt1/2. Thus, besides estimating SI, our novel model can quantify differences in insulin-independent glucose disposal mechanisms important for diabetes pathophysiology.

A double-blind, randomized clinical trial comparing soybean oil-based versus olive oil-based lipid emulsions in adult medical-surgical intensive care unit patients requiring parenteral nutrition.

OBJECTIVE: Parenteral nutrition has been associated with metabolic and infectious complications in intensive care unit patients. The underlying mechanism for the high risk of complications is not known but may relate to the proinflammatory effects of soybean oil-based lipid emulsions, the only Food and Drug Administration-approved lipid formulation for clinical use. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Medical-surgical intensive care units from a major urban teaching hospital and a tertiary referral university hospital. PATIENTS: Adult medical-surgical intensive care unit patients. INTERVENTION: Parenteral nutrition containing soybean oil-based (Intralipid) or olive oil-based (ClinOleic) lipid emulsions. MEASUREMENTS: Differences in hospital clinical outcomes (nosocomial infections and noninfectious complications), hospital length of stay, glycemic control, inflammatory and oxidative stress markers, and granulocyte and monocyte functions between study groups. RESULTS: A total of 100 patients were randomized to either soybean oil-based parenteral nutrition or olive oil-based parenteral nutrition for up to 28 days. A total of 49 patients received soybean oil-based parenteral nutrition (age 51 ± 15 yrs, body mass index 27 ± 6 kg/m2, and Acute Physiology and Chronic Health Evaluation II score 15.5 ± 7 [±SD]), and a total of 51 patients received olive oil-based lipid emulsion in parenteral nutrition (age 46 ± 19 yrs, body mass index 27 ± 8 kg/m2, and Acute Physiology and Chronic Health Evaluation II score 15.1 ± 6 [±SD]) for a mean duration of 12.9 ± 8 days. The mean hospital blood glucose concentration during parenteral nutrition was 129 ± 14 mg/dL, without differences between groups. Patients treated with soybean oil-based and olive oil-based parenteral nutrition had a similar length of stay (47 ± 47 days and 41 ± 36 days, p = .49), mortality (16.3% and 9.8%, p = .38), nosocomial infections (43% vs. 57%, p = .16), and acute renal failure (26% vs. 18%, p = .34). In addition, there were no differences in inflammatory and oxidative stress markers or in granulocyte and monocyte functions between groups. CONCLUSION: The administration of parenteral nutrition containing soybean oil-based and olive oil-based lipid emulsion resulted in similar rates of infectious and noninfectious complications and no differences in glycemic control, inflammatory and oxidative stress markers, and immune function in critically ill adults.

1-h Glucose During Oral Glucose Tolerance Test Predicts Hyperglycemia Relapse-Free Survival in Obese Black Patients With Hyperglycemic Crises.

Objective: Approximately 50% of obese Black patients with unprovoked diabetic ketoacidosis (DKA) or severe hyperglycemia (SH) at new-onset diabetes achieve near-normoglycemia remission with intensive insulin treatment. Despite the initial near-normoglycemia remission, most DKA/SH individuals develop hyperglycemia relapse after insulin discontinuation. Traditional biomarkers such as normal glucose tolerance at the time of remission were not predictive of hyperglycemia relapse. We tested whether 1-h plasma glucose (1-h PG) at remission predicts hyperglycemia relapse in Black patients with DKA/SH. Methods: Secondary analysis was performed of two prospective randomized controlled trials in 73 patients with DKA/SH at the safety net hospital with a median follow-up of 408 days. Patients with DKA/SH underwent a 5-point, 2-h 75-g oral glucose tolerance test after hyperglycemia remission. Hyperglycemia relapse is defined by fasting blood glucose (FBG) > 130 mg/dl, random blood glucose (BG) >180 mg/dl, or HbA1c > 7%. Results: During the median 408 (interquartile range: 110-602) days of follow-up, hyperglycemia relapse occurred in 28 (38.4%) participants. One-hour PG value ≥199 mg/dl discriminates hyperglycemia relapse (sensitivity: 64%; specificity: 71%). Elevated levels of 1-h PG (≥199 mg/dl) were independently associated with hyperglycemia relapse (adjusted hazard ratio: 2.40 [95% CI: 1.04, 5.56]). In a multivariable model with FBG, adding 1-h PG level enhanced the prediction of hyperglycemia relapse, with significant improvements in C-index (Δ: +0.05; p = 0.04), net reclassification improvement (NRI: 48.7%; p = 0.04), and integrated discrimination improvement (IDI: 7.8%; p = 0.02) as compared with the addition of 2-h PG (NRI: 20.2%; p = 0.42; IDI: 1.32%; p = 0.41) or HbA1c (NRI: 35.2%; p = 0.143; IDI: 5.8%; p = 0.04). Conclusion: One-hour PG at the time of remission is a better predictor of hyperglycemia relapse than traditional glycemic markers among obese Black patients presenting with DKA/SH. Testing 1-h PG at insulin discontinuation identifies individuals at high risk of developing hyperglycemia relapse.

Effects of oral and intravenous fat load on blood pressure, endothelial function, sympathetic activity, and oxidative stress in obese healthy subjects.

We compared the effects of high and low oral and intravenous (iv) fat load on blood pressure (BP), endothelial function, autonomic nervous system, and oxidative stress in obese healthy subjects. Thirteen obese subjects randomly received five 8-h infusions of iv saline, 20 (32 g, low iv fat) or 40 ml/h intralipid (64 g, high iv fat), and oral fat load at 32 (low oral) or 64 g (high oral). Systolic BP increased by 14 ± 10 (P = 0.007) and 12 ± 9 mmHg (P = 0.007) after low and high iv lipid infusions and by 13 ± 17 (P = 0.045) and 11 ± 11 mmHg (P = 0.040) after low and high oral fat loads, respectively. The baseline flow-mediated dilation was 9.4%, and it decreased by 3.8 ± 2.1 (P = 0.002) and 4.1 ± 3.1% (P < 0.001) after low and high iv lipid infusion and by 3.8 ± 1.8 (P = 0.002) and 5.0 ± 2.5% (P < 0.001) after low and high oral fat load, respectively. Oral and iv fat load stimulated oxidative stress, increased heart rate, and decreased R-R interval variability. Acute iv fat load decreased blood glucose by 6-10 mg/dl (P < 0.05) without changes in insulin concentration, whereas oral fat increased plasma insulin by 3.7-4.0 µU/ml (P < 0.01) without glycemic variations. Intravenous saline and both oral and iv fat load reduced leptin concentration from baseline (P < 0.01). In conclusion, acute fat load administered orally or intravenously significantly increased blood pressure, altered endothelial function, and activated sympathetic nervous system by mechanisms not likely depending on changes in leptin, glucose, and insulin levels in obese healthy subjects. Thus, fat load, independent of its source, has deleterious hemodynamic effects in obese subjects.

Long-term changes in carbohydrate tolerance, insulin secretion and action in African-American patients with obesity and history of hyperglycemic crises.

INTRODUCTION: Many African-Americans (AA) with obesity with newly diagnosed diabetes presenting with diabetic ketoacidosis (DKA) or severe hyperglycemia (SH) discontinue insulin therapy and achieve near-normoglycemia remission (hemoglobin A1c (HbA1c) <7%, fasting blood glucose (FBG) <130 mg/dL) and able to be managed on oral antidiabetic agents (OAD) during follow-up. Using combined data from two randomized controlled trials, we assessed long-term carbohydrate tolerance and changes in insulin sensitivity and insulin secretion. RESEARCH DESIGN AND METHODS: Seventy-five participants with DKA (n=33) and SH (n=42) underwent 2-hour 75 g oral glucose tolerance test (OGTT) after insulin discontinuation and every 6 months until hyperglycemia relapse (FBG ≥130 mg/dL, HbA1c >7% or two random BG ≥180 mg/dL) while treated with OAD (metformin, sitagliptin or pioglitazone) or placebo. Glucose tolerance status was defined as per the American Diabetes Association. Sensitivity index (Si) was calculated by oral minimal model, insulin secretion as the incremental area under the curve of insulin (IncreAUCi) and disposition index (DI) as Si×IncreAUCi. RESULTS: During remission, OGTT showed normal glucose tolerance (NGT) (n=9 (12%)), prediabetes (n=34 (45%)) and diabetes (n=32 (43%)). DI and Si were higher in patients with NGT versus prediabetes versus diabetes (p<0.001), while IncreAUCi was not significantly different among NGT, prediabetes and diabetes (p=0.14). Achieving NGT status did not prolong near-normoglycemia remission. OAD treatment significantly prolonged hyperglycemia relapse-free survival (log-rank p=0.0012) compared with placebo and was associated with lower hyperglycemia relapse (HR: 0.45, 95% CI: (0.21 to 0.96), p=0.04). CONCLUSIONS: In AA patients with obesity with history of DKA and SH, near-normoglycemia remission is associated with improved insulin secretion and action with half of patients achieving NGT or prediabetes, and only half having diabetes on OGTT. NGT and prediabetes on OGTT were not associated with prolonged hyperglycemia relapse-free survival. TRIAL REGISTRATION NUMBER: NCT01099618, NCT00426413.

A Comparison of Inpatient Cost Per Day in General Surgery Patients with Type 2 Diabetes Treated with Basal-Bolus versus Sliding Scale Insulin Regimens.

BACKGROUND: The identification of cost-effective glycaemic management strategies is critical to hospitals. Treatment with a basal-bolus insulin (BBI) regimen has been shown to result in better glycaemic control and fewer complications than sliding scale regular insulin (SSI) in general surgery patients with type 2 diabetes mellitus (T2DM), but the effect on costs is unknown. OBJECTIVE: We conducted a post hoc analysis of the RABBIT Surgery trial to examine whether total inpatient costs per day for general surgery patients with T2DM treated with BBI (n = 103) differed from those for patients with T2DM treated with SSI (n = 99) regimens. METHODS: Data were collected from patient clinical and hospital billing records. Charges were adjusted to reflect hospital costs. General linearized models were used to estimate the risk-adjusted effects of BBI versus SSI treatment on average total inpatient costs per day. RESULTS: Risk-adjusted average total inpatient costs per day were $US5404. Treatment with BBI compared with SSI reduced average total inpatient costs per day by $US751 (14%; 95% confidence interval [CI] 20-4). Being treated in a university medical centre, being African American or having a bowel procedure or higher-volume pharmacy use significantly reduced costs per day. CONCLUSIONS: In general surgery patients with T2DM, a BBI regimen significantly reduced average total hospital costs per day compared with an SSI regimen. BBI has been shown to improve outcomes in a randomized controlled trial. Those results, combined with our findings regarding savings, suggest that hospitals should consider adopting BBI regimens in patients with T2DM undergoing surgery.

Randomized Controlled Study of Metformin and Sitagliptin on Long-term Normoglycemia Remission in African American Patients With Hyperglycemic Crises.

OBJECTIVE: After intensive insulin treatment, many obese African American patients with new-onset diabetic ketoacidosis (DKA) and severe hyperglycemia are able to achieve near-normoglycemia remission. The optimal treatment to prevent hyperglycemic relapses after remission is not known. RESEARCH DESIGN AND METHODS: This prospective, 4-year, placebo-controlled study randomly assigned 48 African American subjects with DKA and severe hyperglycemia to metformin 1,000 mg daily (n = 17), sitagliptin 100 mg daily (n = 16), or placebo (n = 15) after normoglycemia remission. Hyperglycemic relapse was defined as fasting glucose >130 mg/dL (7.2 mmol/L) and HbA1c >7.0% (53 mmol/mol). Oral glucose tolerance tests were conducted at randomization and at 3 months and then every 6 months for a median of 331 days. Oral minimal model and incremental area under the curve for insulin (AUCi) were used to calculate insulin sensitivity (Si) and ß-cell function, respectively. Disposition index (DI) was calculated as a product of Si and incremental AUCi. RESULTS: Relapse-free survival was higher in sitagliptin and metformin (P = 0.015) compared with placebo, and mean time to relapse was significantly prolonged in the metformin and sitagliptin groups compared with the placebo group (480 vs. 305 days, P = 0.004). The probability of relapse was significantly lower for metformin (hazard ratio 0.28 [95% CI 0.10-0.81]) and sitagliptin (0.31 [0.10-0.98]) than for placebo. Subjects who remained in remission had a higher DI (P = 0.02) and incremental AUCi (P < 0.001) than those with hyperglycemia relapse without significant changes in Si. CONCLUSIONS: This study shows that near-normoglycemia remission was similarly prolonged by treatment with sitagliptin and metformin. The prolongation of remission was due to improvement in ß-cell function.

Clinical effects of once-weekly exenatide for the treatment of type 2 diabetes mellitus.

PURPOSE: The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, administration, dosage, place in therapy, and cost of extended-release exenatide are reviewed. SUMMARY: Regular-release exenatide has a half-life of 2.4 hours and is administered twice daily. In order to allow for once-weekly administration, exenatide was encapsulated in poly(lactic-co-glycolic acid) microspheres, a biodegradable polymer. After subcutaneous injection, the microspheres slowly degrade, and the drug is released. A single injection of extended-release exenatide reaches maximum plasma concentration after 4-8 hours and remains at therapeutic levels for 8-16 hours, depending on the dosage. Based on the pharmacokinetics of a single dose, researchers determined that 0.8- and 2-mg once-weekly doses were likely to maintain therapeutic levels in the serum. Patients who used extended-release exenatide monotherapy had significantly lower glycosylated hemoglobin (HbA1c) levels and lost more weight than those receiving sitagliptin or pioglitazone (p < 0.05). In combination with metformin, extended-release exenatide reduced HbA1c levels more than did insulin glargine. This new formulation reduced HbA1c levels by 1.5-1.9%, fasting blood glucose concentrations by 31-42 mg/dL, and weight by 2.3-3.7 kg. The most common adverse events were injection-site reactions and transient nausea. Postmarketing reports have described acute pancreatitis and acute necrotizing or hemorrhagic pancreatitis in patients treated with exenatide. The published average wholesale price for a one-month supply of extended-release exenatide 2 mg is $388. CONCLUSION: Extended-release exenatide taken once weekly is an effective second-line therapy for patients with type 2 diabetes who have not achieved glycemic goals with metformin alone.

Vascular effects of intravenous intralipid and dextrose infusions in obese subjects.

Hyperglycemia and elevated free fatty acids (FFA) are implicated in the development of endothelial dysfunction. Infusion of soy-bean oil-based lipid emulsion (Intralipid®) increases FFA levels and results in elevation of blood pressure (BP) and endothelial dysfunction in obese healthy subjects. The effects of combined hyperglycemia and high FFA on BP, endothelial function and carbohydrate metabolism are not known. Twelve obese healthy subjects received four random, 8-h IV infusions of saline, Intralipid 40 mL/h, Dextrose 10% 40 mL/h, or combined Intralipid and dextrose. Plasma levels of FFA increased by 1.03±0.34 mmol/L (p=0.009) after Intralipid, but FFAs remained unchanged during saline, dextrose, and combined Intralipid and dextrose infusion. Plasma glucose and insulin concentrations significantly increased after dextrose and combined Intralipid and dextrose (all, p<0.05) and were not different from baseline during saline and lipid infusion. Intralipid increased systolic BP by 12±9 mmHg (p<0.001) and diastolic BP by 5±6 mmHg (p=0.022),and decreased flow-mediated dilatation (FMD) from baseline by 3.2%±1.4% (p<0.001). Saline and dextrose infusion had neutral effects on BP and FMD. The co-administration of lipid and dextrose decreased FMD by 2.4%±2.1% (p=0.002) from baseline, but did not significantly increase systolic or diastolic BP. Short-term Intralipid infusion significantly increased FFA and BP; in contrast, FFA and BP were unchanged during combined infusion of Intralipid and dextrose. Combined Intralipid and dextrose infusion resulted in endothelial dysfunction similar to Intralipid alone.

Perioperative glucose control in the diabetic or nondiabetic patient.

Patients with diabetes are more likely to undergo surgery than nondiabetics, and maintaining glycemic control in subjects with diabetes can be challenging during the perioperative period. Surgery in diabetic patients is associated with longer hospital stay, higher health care resource utilization, and greater perioperative mortality. In addition, several observational and interventional studies have indicated that hyperglycemia is associated with adverse clinical outcomes in surgical and critically ill patients. This paper reviews the pathophysiology of hyperglycemia during trauma and surgical stress and will provide practical recommendations for the preoperative, intraoperative, and postoperative care of diabetic patients.