New developments in the treatment and monitoring of type 1 diabetes mellitus

In recent years, insulin analogues are the benefits of the use in functional intensive insulin therapy for the treatment of diabetes. Shortacting insulin (lispro, aspart and glulisine) and long-acting insulin (glargine and detemir) have been developed for the management of diabetes. Short-acting insulin analogues are an alternative to regular human insulin before meals. These new short-acting insulin analogues show more rapid onset of activity and a shorter duration of action. As a result of these pharmacokinetic differences, an improved postprandial glycemic control is achieved, without increasing the risk of hypoglycemia. In addition, these insulin analogues can be administered immediately before a meal. The long-acting insulin analogues provide basal insulin levels for 24 h when administered once (glargine) or two (detemir) daily. Compared with previous intermediate- or long-acting conventional insulin, these insulins shows a flat profile of plasma insulin levels . The use of these long-acting insulin analogues appears to be associated with a reduced incidence of hypoglycemia, especially at night. The availability of these new insulin analogues has the potential to significantly improve long-term control over blood glucose in diabetic patients. In recent years more and more frequently the method of multiple daily injections (MDI) of insulin is being replaced by the method of continuous subcutaneous insulin infusion (CSII). It is the most physiological way to administer insulin. In recent years treatment with insulin pumps has been used more frequently in the pediatric patients and in the treatment of diabetes in pregnancy. Use of continuous glucose monitoring systems enables detection of glycemia fluctuations unrevealed by selfmonitoring of blood glucose, such as night hypoglycemias and early postprandial hyperglycemias. Real-time systems allow to reduce HbA1c levels and limit number of excursions. Non-invasive glucose measurement devices are introduced. Fully automated continuous glucose monitoring systems integrated with insulin pumps operating in closed-loop model, requiring no patient assistance, are still being researched. Commercially available systems operate in open-loop model, where the patient has to decide on administration and dose of insulin.     

A coordinated control strategy for insulin and glucagon delivery in type 1 diabetes

Type 1 diabetes is an autoimmune condition characterised by a pancreatic insulin secretion deficit, resulting in high blood glucose concentrations, which can lead to micro- and macrovascular complications. Type 1 diabetes also leads to impaired glucagon production by the pancreatic α-cells, which acts as a counter-regulatory hormone to insulin. A closed-loop system for automatic insulin and glucagon delivery, also referred to as an artificial pancreas, has the potential to reduce the self-management burden of type 1 diabetes and reduce the risk of hypo- and hyperglycemia. To date, bihormonal closed-loop systems for glucagon and insulin delivery have been based on two independent controllers. However, in physiology, the secretion of insulin and glucagon in the body is closely interconnected by paracrine and endocrine associations. In this work, we present a novel biologically-inspired glucose control strategy that accounts for such coordination. An in silico study using an FDA-accepted type 1 simulator was performed to evaluate the proposed coordinated control strategy compared to its non-coordinated counterpart, as well as an insulin-only version of the controller. The proposed coordinated strategy achieves a reduction of hyperglycemia without increasing hypoglycemia, when compared to its non-coordinated counterpart.     

Glucagon Treatment for Post‐Gastric Bypass Hypoglycemia

Hyperinsulinemic hypoglycemia is a recently described complication of Roux‐en‐Y gastric bypass (RYGB). We hypothesized that glucagon administration would help maintain normal postprandial plasma glucose concentrations by stimulating hepatic glucose output, and if so, represent a new therapeutic option for postbypass hypoglycemia. In this study, we compared the insulin and glycemic response to a mixed meal with and without concomitant glucagon infusion in a patient with severe recurrent hypoglycemia after RYGB. Although effective in transiently raising postprandial plasma glucose values, glucagon infusion was also associated with higher insulin concentrations, and failed to prevent symptomatic hypoglycemia. This case demonstrates that glucagon may have limited clinical utility in the treatment of post‐RYGB hyperinsulinemic hypoglycemia.     

Repeated measures random forests (RMRF): Identifying factors associated with nocturnal hypoglycemia

Nocturnal hypoglycemia is a common phenomenon among patients with diabetes and can lead to a broad range of adverse events and complications. Identifying factors associated with hypoglycemia can improve glucose control and patient care. We propose a repeated measures random forest (RMRF) algorithm that can handle nonlinear relationships and interactions and the correlated responses from patients evaluated over several nights. Simulation results show that our proposed algorithm captures the informative variable more often than naïvely assuming independence. RMRF also outperforms standard random forest and extremely randomized trees algorithms. We demonstrate scenarios where RMRF attains greater prediction accuracy than generalized linear models. We apply the RMRF algorithm to analyze a diabetes study with 2524 nights from 127 patients with type 1 diabetes. We find that nocturnal hypoglycemia is associated with HbA1c, bedtime blood glucose (BG), insulin on board, time system activated, exercise intensity, and daytime hypoglycemia. The RMRF can accurately classify nights at high risk of nocturnal hypoglycemia.     

Hypoglycémie spontanée et insuffisance rénale chronique.

Although glucose intolerance occurs as a consequence of chronic renal failure, improvement of a diabetic state by deterioration of renal function is a well known phenomenon. Recently occasional cases of spontaneous hypoglycemia in patients with chronic renal failure have been reported; two such cases and the results of metabolic studies are described in this paper. Pituitary, thyroid and adrenal function appeared to be normal. The results of an oral glucose tolerance test were normal; an appropriate insulin response was demonstrated in one patient, and a slightly elevated basal insulin value with a delayed insulin response to oral administration of glucose was demonstrated in the other. An insulin tolerance test did not support the hypothesis of increased insulin sensitivity as a factor, and the growth hormone response to hypoglycemia was normal. An intravenous glucagon test caused a subnormal increase in plasma glucose concentration, and the intravenous administration of tolbutamide produced hypoglycemia without an increase insulin sensitivity as a factor, and the growth hormone response to hypoglycemia was normal. An intravenous glucagon test caused a subnormal increase in plasma glucose concnetration, and the intravenous administration of tolbutamide produced hypoglycemia without an increase in insulin values. The plasma alanine concentration was low and the proinsulin/insulin ratio was increased. The origin of this hypoglycemia is not clear but is probably multifactorial. However, low hepatic glycogen stores and inadequate gluconeogenesis due to substrate deficiency seem to be involved.     

Carbohydrates modulate opiate receptor mediated mechanisms during postprandial endocrine function

The present study was designed to determine the role of carbohydrates during naloxone-induced opiate receptor blockade upon the postprandial rise of plasma somatostatin (SLI), insulin and pancreatic polypeptide (PP) levels in response to protein and fat test meals in conscious dogs. Test meals consisting of 50 g liver extract + 50 g sucrose or 50 g corn oil + 50 g sucrose dissolved in 300 ml water were instilled intragastrically, respectively. Additionally, liver extract and fat meals were given with a concomitant intravenous infusion of glucose. To all test meals either naloxone (4 mg) or saline was added. The addition of sucrose to liver extract or the infusion of i.v. glucose during the liver meal abolished the inhibitory effect of naloxone on the rise of postprandial somatostatin levels which has been described recently. The addition of carbohydrate either orally or intravenously to the fat meal resulted in an even stimulatory effect of naloxone upon the rise of postprandial somatostatin levels. Insulin levels were not changed during liver extract + sucrose or i.v. glucose, respectively. When sucrose or i.v. glucose was administered together with the fat meal the addition of naloxone augmented postprandial insulin secretion. Pancreatic polypeptide (PP) release was augmented during the combination of sucrose or i.v. glucose with the fat and liver meal when naloxone was present in the meals. The present data demonstrate that the addition of carbohydrates either orally or intravenously to fat and protein meals modulates the effect of endogenous opiates in the regulation of postprandial somatostatin, insulin and pancreatic polypeptide release in dogs in a way that carbohydrates induce inhibitory mechanisms that are mediated via endogenous opiate receptors.     

Postprandial hyperglycemia and endothelial function in type 2 diabetes: focus on mitiglinide

ABSTRACT: The risk of cardiovascular complication in a diabetes patient is similar to that in a nondiabetic patient with a history of myocardial infarction. Although intensive control of glycemia achieved by conventional antidiabetic agents decreases microvascular complications such as retinopathy and nephropathy, no marked effect has been reported on macrovascular complications or all-cause mortality. Evidence from VADT, ACCORD, and ADVANCE would suggest that glycemic control has little effect on macrovascular outcomes. Moreover, in the case of ACCORD, intensive glycemic control may be associated with an increased risk of mortality. There is sufficient evidence that suggests that postprandial hyperglycemia may be an independent risk factor for cardiovascular disease in diabetes patients. However, there are no prospective clinical trials supporting the recommendation that lowering postprandial blood glucose leads to lower risk of cardiovascular outcomes. Mitiglinide is a short-acting insulinotropic agent used in type 2 diabetes treatment. It has a rapid stimulatory effect on insulin secretion and reduces postprandial plasma glucose level in patients with type 2 diabetes. Because of its short action time, it is unlikely to exert adverse effects related to hypoglycemia early in the morning and between meals. Mitiglinide reduces excess oxidative stress and inflammation, plays a cardioprotective role, and improves postprandial metabolic disorders. Moreover, mitiglinide add-on therapy with pioglitazone favorably affects the vascular endothelial function in type 2 diabetes patients. These data suggest that mitiglinide plays a potentially beneficial role in the improvement of postprandial hyperglycemia in type 2 diabetes patients and can be used to prevent cardiovascular diseases. Although the results of long-term, randomized, placebo-controlled trials for determining the cardiovascular effects of mitiglinide on clinical outcomes are awaited, this review is aimed at summarizing substantial insights into this topic.     

Relationship Between Hunger-Satiety Feelings and Various Metabolic Parameters in Women with Obesity During Controlled Weight Loss

Objective : Satiety plays an important role in weight control. The meaning of fasting hormone levels and satiety feelings, and how post-absorptive changes after meals high in carbohydrate regulate appetite remains to be demonstrated. Research Methods and Procedures : Prospective metabolic study with 25 non-diabetic obese women at the Energy Metabolism Research Unit of the Department of Nutrition Sciences, University of Alabama at Birmingham. We analyzed fasting and postprandial ratings of hunger-satiety and values of various metabolic parameters (serum glucose and insulin, plasma cholecystokinin, respiratory quotient) during controlled weight loss. The postprandial measures were assessed following a test meal providing 320 kcal and yielding a food quotient of 0.89. Results : In the fasting state, there was no correlation between hunger-satiety ratings and any of the measured metabolic parameters. Under postprandial conditions, satiety was positively related to glucose (p = 0.002) and insulin (p = 0.002) responses to the test meal. In multivariate analysis including glucose, insulin, cholecystokinin, hunger-satiety ratings and respiratory quotient, insulin was the only independent predictor of satiety in the postprandial state. Discussion : These data suggest an association between the endogenous insulin response and feelings of postprandial satiety. Insulin's satiation properties, which could well be mediated by other hormones, may represent a primary factor of food intake regulation after meals relatively high in carbohydrate.     

How Patients With Type 1 Diabetes Translate Continuous Glucose Monitoring Data into Diabetes Management Decisions

Objective: To understand how patients use continuous glucose monitoring (CGM) data in their diabetes management.Methods: We surveyed patients who regularly used CGM (>6 days per week), using 70 questions, many scenario-based. The survey had 6 sections: patient characteristics, general CGM use, hypoglycemia prevention and management, hyperglycemia prevention and management, insulin dosing adjustments (both for incidental hyperglycemia not at meals and at mealtimes), and real-time use versus retrospective analysis.Results: The survey was completed by 222 patients with type 1 diabetes. In response to a glucose of 220 mg/dL, the average correction dose adjustment based on rate of change arrows varied dramatically. Specifically, when the CGM device showed 2 arrows up (glucose increasing >3 mg/dL/minute), respondents stated they would increase their correction bolus, on average, by 140% (range, 0 to 600%). Conversely, 2 arrows down (glucose decreasing >3 mg/dL/minute) caused respondents to reduce their dose by 42%, with 24% omitting their dose entirely. Furthermore, 59% of respondents stated they would delay a meal in response to rapidly rising glucose, whereas 60% would wait until after a meal to bolus in response to falling glucose levels. With a glucose value of 120 mg/dL and a falling glucose trend, 70% of respondents would prophylactically consume carbohydrates to avoid hypoglycemia.Conclusion: CGM users utilize CGM data to alter multiple aspects of their diabetes care, including insulin dose timing, dose adjustments, and in hypoglycemia prevention. The insulin adjustments are much larger than common recommendations. Additional studies are needed to determine appropriate insulin adjustments based on glucose trend data.Abbreviations: A_1c = hemoglobin A_1c CGM = continuous glucose monitoring ROC = rate of change SMBG = self-monitored blood glucose     

Effects of dietary D-psicose on diurnal variation in plasma glucose and insulin concentrations of rats

The effects of supplemental D-psicose in the diet on diurnal variation in plasma glucose and insulin concentrations were investigated in rats. Forty-eight male Wistar rats were divided into four groups. Each group except for the control group was fed a diet of 5% D-fructose, D-psicose, or psico-rare sugar (3:1 mixture of D-fructose and D-psicose) for 8 weeks. Plasma glucose levels were lower and plasma insulin levels were higher at all times of day in the psicose and psico-rare sugar groups than in the control and fructose groups. Weight gain was significantly lower in the psicose group than in the control and fructose groups. Liver glycogen content, both before and after meals was higher in the psicose group than in the control and fructose groups. These results suggest that supplemental D-psicose can lower plasma glucose levels and reduce body fat accumulation. Hence, D-psicose might be useful in preventing postprandial hyperglycemia in diabetic patients.     

The human amylin analog, pramlintide, reduces postprandial hyperglucagonemia in patients with type 2 diabetes mellitus.

AIMS: Amylin is a second beta-cell hormone that is normally co-secreted with insulin in response to meals; it complements the effects of insulin in postprandial glucose control, in part by suppressing glucagon secretion. In patients with type 2 diabetes, mealtime administration of the human amylin analog pramlintide markedly improves postprandial glucose excursions. The aim of this study was to examine whether pramlintide reduces the postprandial hyperglucagonemia that is often seen in this patient population. METHODS: Utilizing a single-blind, placebo-controlled crossover design, 24 patients with type 2 diabetes, 12 insulin-treated and 12 non-insulin-treated, underwent a standardized mixed meal test on 2 occasions during which they received, in randomized order, a five-hour intravenous infusion of placebo or pramlintide (100 microg/h). RESULTS: During the placebo infusion, plasma glucose and plasma glucagon concentrations increased substantially after the meal. During the pramlintide infusion, postprandial plasma glucose and plasma glucagon responses were significantly (p < 0.05, all) reduced following ingestion of the same meal, both in the insulin-treated and non-insulin-treated subgroups. CONCLUSION: Supplementation of mealtime amylin with pramlintide reduces postprandial hyperglucagonemia in patients with type 2 diabetes, a mechanism that likely contributes to pramlintide's postprandial glucose-lowering effect.     

Internal model sliding mode control approach for glucose regulation in type 1 diabetes

Patients with type 1 diabetes require insulin therapy to maintain blood glucose levels within safe ranges since their pancreas is unable to complete its function. The development of a closed-loop artificial pancreas capable of maintaining normoglycemia during daily life will dramatically improve the quality of life for insulin-dependent diabetic patients. In this work, a closed-loop control strategy for blood glucose level regulation in type 1 diabetic patients is presented. A robust controller is designed using a combination of internal model and sliding mode control techniques. Also, the controller is provided with a feedforward loop to improve meal compensation. A simulation environment designed for testing the artificial pancreas control algorithms has been used to evaluate the controller. The simulation results show a good controller performance in fasting conditions and meal disturbance rejection, and robustness against model–patient mismatch and meal estimation errors.     

Minimal Reduction in Insulin Dosage with Pramlintide Therapy When Pretreatment Near-Normal Glycemia is Established and Square-Wave Meal Bolus is Used

ObjectiveTo evaluate the effect of near-normal glucose control before initiation of pramlintide therapy and square-wave meal bolus on self-reported hypoglycemia and the percentage change in dosing parameters after attaining the maximum pramlintide dosage.MethodsIn this prospective study, insulin pump–treated patients with type 1 diabetes had insulin dosages optimally titrated on the basis of daily continuous glucose monitoring (CGM). Pramlintide therapy was initiated, and the dosage was increased 15 mcg/meal per week. Insulin dosage was adjusted during 30-minute visits after review of self-monitored blood glucose records, adverse effects, and hypoglycemia diary. Within 2 weeks of achieving a pramlintide dosage of 60 mcg/meal, the second CGM–guided insulin dosage adjustment was done. The primary end point was the percentage change in total basal insulin dosage (TBD) from baseline. The secondary end points were the percentage change in the insulin to carbohydrate ratio (ICR) and the assessment of symptoms of nausea and hypoglycemia during the pramlintide dosing escalation.ResultsNine patients were enrolled. The difference between before and during CGM–guided insulin dosing was a mean (± standard deviation) TBD change of -11.2 ± 13.2% (P = 0.023) and mean ICR change of 7.8 ± 13.4% (P = 0.053). Pramlintide was well tolerated and resulted in decrease in weight and hemoglobin A_1c values. Hypoglycemia occurred in 6 patients during the study; the assistance of another person was not required in any of these cases. No hypoglycemia was reported in the first week of starting pramlintide. Mild to moderate nausea was reported in 6 patients during the titration phase.ConclusionsPatients with near-normal glucose control who use a square-wave bolus may not need initial bolus dosage reduction. With weight loss, small adjustments in both TBD and ICR may be required. Greater incidence of hypoglycemia seen in previous studies may in part be due to mismatched insulin dosing. (Endocr Pract. 2009;15:229-233)     

Evaluating the Impact of Inadequate Meal Consumption on Insulin-Related Hypoglycemia in Hospitalized Patients

ObjectiveMeal intake is sometimes reduced in hospitalized patients. Meal-time insulin administration can cause hypoglycemia when a meal is not consumed. Inpatient providers may avoid ordering meal-time insulin due to hypoglycemia concerns, which can result in hyperglycemia. The frequency of reduced meal intake in hospitalized patients remains inadequately determined. This quality improvement project evaluates the percentage of meals consumed by hospitalized patients with insulin orders and the resulting risk of postmeal hypoglycemia (blood glucose [BG] <70 mg/dL, <3.9 mmol/L).MethodsThis was a retrospective quality improvement project evaluating patients with any subcutaneous insulin orders hospitalized at a regional academic medical center between 2015 and 2017. BG, laboratory values, point of care, insulin administration, diet orders, and percentage of meal consumed documented by registered nurses were abstracted from electronic health records.ResultsMeal consumption ≥50% was observed for 85% of meals with insulin orders, and bedside registered nurses were accurate at estimating this percentage. Age ≥65 years was a risk factor for reduced meal consumption (21% of meals 0%-49% consumed, P < .05 vs age < 65 years [12%]). Receiving meal-time insulin and then consuming only 0% to 49% of a meal (defined here as a mismatch) was not rare (6% of meals) and increased postmeal hypoglycemia risk. However, the attributable risk of postmeal hypoglycemia due to this mismatch was low (4 events per 1000) in patients with premeal BG between 70 and 180 mg/dL.ConclusionThis project demonstrates that hospitalized patients treated with subcutaneous insulin have a low attributable risk of postmeal hypoglycemia related to inadequate meal intake.     

Hypoglycemias.

Low plasma glucose concentrations that may or may not be sufficiently low to result in symptoms can be observed as a concomitant of several diverse diseases. Treatment of the primary underlying disorder usually alleviates the hypoglycemia. For patients whose primary symptom is that of hypoglycemia, it is essential to confirm that the plasma glucose concentration is low during the occurrence of symptoms. Symptoms that occur after meals usually are mild and rarely signify serious disease. With rare exceptions, hypoglycemia resulting in major symptoms occurs in the food-deprived state. Lower concentrations of plasma insulin and C-peptide and a concomitant low plasma glucose are major clues to a correct diagnosis.     

Effect of a long-acting somatostatin derivative SMS 201-995 (sandostatin) on glucose homeostasis in type I diabetes mellitus

The infusion of natural somatostatin (SRIF) has been able to partially correct postprandial hyperglycemic reactions in insulin-dependent diabetes mellitus (IDDM). SMS 201-995 (Sandostatin) is a long-acting derivative with a growth hormone-suppressive effect 10-60 times more potent than the native peptide. The effect of SMS 201-995 (50 micrograms s.c.) on glucose control by exogenous insulin has been documented in a series of type I diabetics after stabilization of blood sugar by an artificial pancreas. Inhibition of counterregulatory mechanisms significantly diminished the postprandial hyperglycemia, and insulin requirements, both total and 2 h after meals, were markedly decreased. Also the effect of a single s.c. injection of 100 micrograms SMS 201-995 on the dawn phenomenon in a patient with poorly adjustable diabetes was investigated. The glucose escape observed during the control night was blocked by SMS 201-995. Thus, the stabilizing action of this peptide on postprandial and nocturnal hyperglycemia in unstable diabetes warrants further studies.     

Dietary Myoinositol Results in Lower Urine Glucose and in Lower Postprandial Plasma Glucose in Obese Insulin Resistant Rhesus Monkeys.

In a previous study, D-chiroinositol added to a meal (0.5 g/kg) resulted in significantly lower postprandial plasma glucose concentrations without an increase in insulin concentrations in obese insulin-resistant monkeys. The present report describes the effects of another isomer of inositol, myoinositol, on postprandial plasma glucose and insulin concentrations and on urine glucose concentrations in 6 similarly insulin-resistant monkeys. The three 5 day study periods included a control period (liquid diet ad libitum) and 2 experimental periods (liquid diet ad libitum with either 1.5 g/kg/day myoinositol or D-chiroinositol added). Twenty-four hour urine samples were collected during each 5 day period. On the sixth day of each period the monkeys were anesthetized 110 min after completing either the control meal (15 ml/kg) or the experimental meals (1.5 g/kg myoinositol or D-chiroinositol) and plasma samples were obtained at 120, 150,180, 210, 240, 270 and 300 min. The plasma glucose concentration was lower after the meal with myoinositol compared to the control meal at 120, 150 and 180 min (p's<0.05). The plasma insulin concentration was lower after the meal with myoinositol compared to the control meal at 150 and 180 min (p's<0.05). In addition, 24 hour urine glucose concentrations were lower during the myoinositol diet compared to the control diet (p<0.001). The plasma glucose concentration was lower after the meal with D-chiroinositol compared to the control meal at 150, 240, 270 and 300 min (p's≥0.05). In obese insulin-resistant monkeys, myoinositol added to the diet lowers urine glucose concentrations and both myoinositol and D-chiroinositol added to a meal lower postprandial plasma glucose concentrations without increasing postprandial insulin concentrations. Therefore, myoinositol, like D-chiroinositol, may be a useful agent for reducing meal-induced hyperglycemia without inducing hyperinsulinemia in insulin-resistant subjects.     

Development of individual insulin infusion profiles for open loop infusion systems

A computer controlled syringe-type insulin infusion pump storing up to 254 different infusion rates, eight different meal programs and two different basal rates automatically changeable during 24 h in EPROM was used for insulin infusion applying a wavy step profile. This profile approaching the physiological postprandial insulin secretion of the B-cell was calculated by an algorithm following the biphasic insulin secretion model proposed by E. Cerasi . The computer program for the open loop infusion device simulated the feed-back structure of a closed loop insulin secretion control by an algorithm based upon a theoretical postprandial blood sugar profile. Fifteen unstable juvenile onset insulin requiring diabetics could be well controlled after two to three days of an intravenous open loop insulin infusion program. The programs consisted of two constant basal rates and superimposed wavy step profile programs activated at the beginning of each meal. The preabsorptive bolus or cephalic phase was an additional tool both for improved postprandial blood sugar control and further reduction of insulin consumption. The programmable insulin infusion device proved as a valuable tool for the study of a sophisticated insulin infusion profile suitable as well for open loop as for closed loop insulin infusion systems.     

Grey-box pharmacokinetic/pharmacodynamic modelling of a euglycaemic clamp study

Grey-box pharmacokinetic/pharmacodynamic (PK/PD) modelling is presented as a promising way of modelling the pharmacokinetics and pharmacodynamics of the in vivo system of insulin and glucose and to estimate model and derived PK/PD parameters. The concept behind grey-box modelling consists in using a priori physiological knowledge along with information from data in the estimation of model parameters. The PK/PD properties of two types of insulin are investigated in a euglycaemic clamp study where a single bolus of insulin is injected subcutaneously. The effect of insulin on the glucose disappearance is investigated by artificially maintaining a blood glucose concentration close to the normal fasting level. The infused glucose needed to maintain the clamped blood glucose concentration can therefore be used as a measure for the glucose utilization. The PK and PD parameters are successfully estimated simultaneously thereby describing the uptake, distribution, and effect of the two different types of insulin.     

Hypoglycemia: Still The Limiting Factor in the Glycemic Management of Diabetes

ObjectiveTo review the prevalence of, risk factors for, and prevention of hypoglycemia from the perspective of the pathophysiologic aspects of glucose counterregulation in diabetes.MethodsThis review is based on personal experience and research and the relevant literature.ResultsAlthough it can result from insulin excess alone, iatrogenic hypoglycemia is generally the result of the interplay of therapeutic insulin excess and compromised defenses against declining plasma glucose concentrations. Failure of β-cells of the pancreas—early in patients with type 1 diabetes mellitus but later in those with type 2 diabetes mellitus (T2DM)—causes loss of the first 2 physiologic defenses: a decrease in insulin and an increase in glucagon. Such patients are critically dependent on epinephrine, the third physiologic defense, and neurogenic symptoms that prompt the behavioral defense (carbohydrate ingestion). An attenuated sympathoadrenal response to declining glucose levels—caused by recent antecedent hypoglycemia, prior exercise, or sleep—causes hypoglycemia-associated autonomic failure (HAAF) and thus a vicious cycle of recurrent hypoglycemia. Accordingly, hypoglycemia is infrequent early in T2DM but becomes increasingly more frequent in advanced (absolutely endogenous insulin-deficient) T2DM, and risk factors for HAAF include absolute endogenous insulin deficiency; a history of severe hypoglycemia, hypoglycemia unawareness, or both; and aggressive glycemic therapy per se.ConclusionBy practicing hypoglycemia risk reduction— addressing the issue, applying the principles of aggressive glycemic therapy, and considering both the conventional risk factors and those indicative of HAAF— it is possible both to improve glycemic control and to minimize the risk of hypoglycemia in many patients. (Endocr Pract. 2008;14:750-756)