Association between antihypertensive drug use and hypoglycemia: a case-control study of diabetic users of insulin or sulfonylureas

Lower Incidence of Hypoglycemia With Angiotensin Receptor Blocker Versus ACE Inhibitor Therapy in People With or Without Diabetes

This article describes a study examining the association between treatment with ACE inhibitors or angiotensin receptor blockers (ARBs) and incident hypoglycemia in patients with or without diabetes who were admitted to the internal medicine departments of a tertiary hospital in the Tel Aviv district of Israel. The authors found that treatment with ARBs, but not ACE inhibitors, compared with treatment with neither, was associated with a reduced risk of hypoglycemia regardless of diabetes status.

Concomitant Use of Sulfonylureas and β-Blockers and the Risk of Severe Hypoglycemia Among Patients With Type 2 Diabetes: A Population-Based Cohort Study

OBJECTIVE

The hypoglycemic potential of β-blockers among users of sulfonylureas, drugs that strongly increase the risk of this potentially fatal adverse effect, is not well understood. Our population-based cohort study assessed the potential association between concomitant use of sulfonylureas and β-blockers versus use of sulfonylureas alone and the risk of severe hypoglycemia.

RESEARCH DESIGN AND METHODS

Using the U.K. Clinical Practice Research Datalink Aurum, we included patients initiating sulfonylureas between 1998 and 2020, excluding those with β-blocker use in the past 6 months. Time-dependent Cox models estimated hazard ratios (HRs) with 95% CIs of severe hypoglycemia (hospitalization with or death resulting from hypoglycemia; ICD-10 codes E16.0, E16.1, and E16.2) associated with current concomitant use of sulfonylureas and β-blockers compared with current sulfonylurea use alone, adjusted for baseline confounders. We also compared current concomitant use of sulfonylureas and non-cardioselective versus cardioselective β-blockers.

RESULTS

Our cohort included 252,869 initiators of sulfonylureas (mean age 61.3 years; 43% female). Median follow-up was 7.9 years. The crude incidence rate of severe hypoglycemia was 7.8 per 1,000 per year. Concomitant use of sulfonylureas and β-blockers was associated with an increased risk of severe hypoglycemia compared with sulfonylurea use alone (HR 1.53; 95% CI 1.42-1.65). There was no difference in the risk between concomitant use of sulfonylureas and noncardioselective β-blockers and concomitant use of sulfonylureas and cardioselective β-blockers (HR 0.95; 95% CI 0.74-1.24).

CONCLUSIONS

β-blockers could further increase the risk of severe hypoglycemia when used concurrently with sulfonylureas. β-blocker cardioselectivity did not seem to play a major role in this regard.

An Overview of Clinically Imperative and Pharmacodynamically Significant Drug Interactions of Renin-Angiotensin-Aldosterone System (RAAS) Blockers

INTRODUCTION

Hypertension is a leading cause of cardiovascular disease and chronic kidney disease, resulting in premature death and disability. The Renin-Angiotensin-Aldosterone System (RAAS) blockers, including Angiotensin-Converting Enzyme (ACE) inhibitors or Angiotensin Receptor Blockers (ARBs), are used as first-line antihypertensive therapy to treat hypertensive patients with comorbidities, including diabetes, ischemic heart disease, heart failure, and chronic kidney disease. The use of RAS blockers is associated with the risks, such as hyperkalemia, angioedema, etc. The drugs potentiating them interact pharmacodynamically, resulting in adverse consequences. This review article focuses on the clinically important drug interactions of RAAS blockers.

MATERIALS AND METHODS

The electronic databases, such as Medline/PubMed Central/PubMed, Google Scholar, ScienceDirect, Cochrane Library, Directory of Open Access Journals (DOAJ), Embase, and reference lists were searched to identify relevant articles.

RESULTS

The risk of hyperkalemia may be enhanced potentially in patients receiving a RAS blocker and potassium-sparing diuretics, potassium supplements, trimethoprim, adrenergic betablockers, antifungal agents, calcineurin inhibitors, pentamidine, heparins or an NSAID, concomitantly. The patients taking ACE inhibitors and mTOR inhibitors, DPP4 inhibitors, alteplase, or sacubitril/valsartan concurrently may be at increased risk of developing angioedema.

CONCLUSION

Clinicians, pharmacists, and other healthcare practitioners should be accountable for medication safety. To avoid adverse implications, prescribers and pharmacists must be aware of the drugs that interact with RAAS blockers.

Effect of beta blocker use and type on hypoglycemia risk among hospitalized insulin requiring patients

Background

Although beta blockers could increase the risk of hypoglycemia, the difference between subtypes on hypoglycemia and mortality have not been studied. This study sought to determine the relationship between type of beta blocker and incidence of hypoglycemia and mortality in hospitalized patients.

Methods

We retrospectively identified non-critically ill hospitalized insulin requiring patients who were undergoing bedside glucose monitoring and received either carvedilol or a selective beta blocker (metoprolol or atenolol). Patients receiving other beta blockers were excluded. Hypoglycemia was defined as any glucose < 3.9 mmol/L within 24 h of admission (Hypo_1day) or throughout hospitalization (Hypo_T) and any glucose < 2.2 mmol/L throughout hospitalization (Hypo_severe).

Results

There were 1020 patients on carvedilol, 886 on selective beta blockers, and 10,216 on no beta blocker at admission. After controlling for other variables, the odds of Hypo_1day, Hypo_T and Hypo_severe were higher for carvedilol and selective beta blocker recipients than non-recipients, but only in basal insulin nonusers. The odds of Hypo_1day (odds ratio [OR] 1.99, 95% confidence interval [CI] 1.28, 3.09, p = 0.0002) and Hypo_T (OR 1.38, 95% CI 1.02, 1.86, p = 0.03) but not Hypo_severe (OR 1.90, 95% CI 0.90, 4.02, p = 0.09) were greater for selective beta blocker vs. carvedilol recipients in basal insulin nonusers. Hypo_1day, Hypo_T, and Hypo_severe were all associated with increased mortality in adjusted models among non-beta blocker and selective beta blocker recipients, but not among carvedilol recipients.

Conclusions

Beta blocker use is associated with increased odds of hypoglycemia among hospitalized patients not requiring basal insulin, and odds are greater for selective beta blockers than for carvedilol. The odds of hypoglycemia-associated mortality are increased with selective beta blocker use or nonusers but not in carvedilol users, warranting further study.

Interdisciplinary approach to compensation of hypoglycemia in diabetic patients with chronic heart failure

Diabetes mellitus is a chronic disease requiring lifelong control with hypoglycemic agents that must demonstrate excellent efficacy and safety profiles. In patients taking glucose-lowering drugs, hypoglycemia is a common cause of death associated with arrhythmias, increased thrombus formation, and specific effects of catecholamines due to sympathoadrenal activation. Focus is now shifting from merely glycemic control to multifactorial approach. In the context of individual drugs and classes, this article reviews interdisciplinary strategies evaluating metabolic effects of drugs for treatment of chronic heart failure (CHF) which can mask characteristic hypoglycemia symptoms. Hypoglycemia unawareness and cardiac autonomic neuropathy are discussed. Data suggesting that hypoglycemia modulates immune response are reviewed. The potential role of gut microbiota in improving health of patients with diabetes and CHF is emphasized. Reports stating that nondiabetic CHF patients can have life-threatening hypoglycemia associated with imbalance of thyroid hormones are discussed. Regular glycemic control based on HbA1c measurements and adequate pharmacotherapy remain the priorities in diabetes management. New antihyperglycemic drugs with safer profiles should be preferred in vulnerable CHF patients. Multidrug interactions must be considered. Emerging therapies with reduced hypoglycemia risk, telemedicine, sensor technologies, and genetic testing predicting hypoglycemia risk may help solving the challenges of hypoglycemia in CHF patients with diabetes. Interdisciplinary work may involve cardiologists, diabetologists/endocrinologists, immunologists, gastroenterologists, microbiologists, nutritionists, imaging specialists, geneticists, telemedicine experts, and other relevant specialists. This review emphasizes that systematic knowledge on pathophysiology of hypoglycemia in diabetic patients with CHF is largely lacking and the gaps in our understanding require further discoveries.

Intensive Glycemic Therapy in Patients With Type 2 Diabetes on β-Blockers

OBJECTIVE

Recent studies have suggested that β-blockers may decrease the adverse influence of hypoglycemia and reduce hypoglycemia-associated cardiac arrhythmias and death. We evaluated whether intensive glycemic therapy in patients with diabetes receiving treatment with β-blockers showed beneficial effects for the prevention of cardiovascular events without increased mortality compared with a standard glycemic therapy.

RESEARCH DESIGN AND METHODS

We used Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial data to assess the risks of cardiovascular events, all-cause death, and cardiovascular death in patients with diabetes receiving treatment with β-blockers (n = 3,079) and not receiving treatment with β-blockers (n = 7,145) using Cox proportional hazard models.

RESULTS

In patients receiving treatment with β-blockers, the cumulative event rates for cardiovascular events were significantly lower in the intensive therapy group compared with the standard therapy group (hazard ratio [HR] 0.81; 95% CI 0.67-0.97; P = 0.02), whereas those rates in patients not receiving treatment with β-blockers were not significantly different (HR 0.92; 95% CI 0.78-1.09; P = 0.36). Conversely, the cumulative event rates for all-cause and cardiovascular deaths in patients receiving treatment with β-blockers were not significantly different between the standard therapy and intensive therapy groups (all-cause death: HR 1.08; 95% CI 0.83-1.42; P = 0.54; cardiovascular death: HR 1.05; 95% CI 0.72-1.51; P = 0.79), whereas in patients not receiving treatment with β-blockers, the event rates were significantly higher in the intensive therapy group compared with the standard therapy group (all-cause death: HR 1.25; 95% CI 1.02-1.52; P = 0.02; cardiovascular death: HR 1.43; 95% CI 1.03-1.98; P = 0.03).

CONCLUSIONS

Intensive glycemic therapy may be effective in patients with type 2 diabetes receiving treatment with β-blockers.

Effectiveness of Prior Use of Beta-Blockers for Preventing Adverse Influences of Severe Hypoglycemia in Patients With Diabetes: An Observational Study

The study aimed to identify predictors of severe acute hypertension (≥ 180/110 mmHg) during severe hypoglycemia and to assess the efficacy of prior use of catecholamine-blocking agents for preventing adverse influences in diabetic patients with severe hypoglycemia. We performed a retrospective study between January 2006 and March 2012 to assess diabetic patients with severe hypoglycemia at a single center in Japan. Severe hypoglycemia was defined as the presence of any hypoglycemic symptoms that required the medical assistance of another person after visiting the emergency room by ambulance. Multivariate logistic regression analysis was performed to identify possible predictors of severe hypertension due to severe hypoglycemia and to assess whether prior use of alpha- or beta-blockers is beneficial for the prevention of severe hypertension in diabetic patients with severe hypoglycemia. Multivariate adjustments were made for age, sex, preexisting hypertension, history of ischemic heart disease, blood glucose level upon arrival, estimated GFR, and prior use of alpha- or beta-blockers. A total of 59,602 patients who visited the emergency room were screened and 352 diabetic patients with severe hypoglycemia were enrolled. Incidences of severe hypertension before and at 3 and 6 hours after the initiation of antihypoglycemic treatment were 21.3%, 6.7%, and 0% in patients with type 1 diabetes (n = 61) and 38.8%, 18.2%, and 8.2% in patients with type 2 diabetes (n = 291), respectively. Aging was positively (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.00-1.03; P = 0.02) and female sex was negatively (OR, 0.50; 95% CI, 0.29-0.86; P = 0.01) associated with occurrence of severe hypertension during severe hypoglycemia. In addition, prior use of beta-blockers was negatively associated with occurrence of severe hypertension during severe hypoglycemia using multivariate logistic regression analysis (OR, 0.31; 95% CI, 0.11-0.83; P = 0.02). None of the patients with prior use of beta-blockers had hypokalemia (<3.0 mEq/L). Prior use of beta-blockers may prevent adverse influences such as severe hypertension and hypokalemia during severe hypoglycemia in diabetic patients.

Effects of ACE inhibitors on insulin resistance and lipid profile in children with metabolic syndrome

OBJECTIVE

The aim of this study was to evaluate the effects of using ACE inhibitors on insulin resistance, glucose metabolism, body fat composition, and lipid profile in children over 10 years of age with obesity-associated metabolic syndrome (MS).

METHODS

A total of 53 children with MS, who had been followed for at least one year were included in the study. The sample was divided into two groups: Group 1-30 obese children (13 female, 17 male) who were not using an ACE inhibitor and Group 2-23 obese children (13 female, 10 male) who were using an ACE inhibitor. Anthropometric and laboratory data obtained at baseline and at the 3rd, 6th, and 12th months of follow-up were compared in the two groups.

RESULTS

Comparison of the data in the two groups at 3rd, 6th, and 12th months revealed no statistically significant differences in terms of weight standard deviation score (SDS), body mass index SDS, weight for height percentile, body fat percentage, and very low-density lipoprotein (VLDL)values. However, there were statistically significant differences in mean glucose and insulin levels, homeostasis model assessment for insulin resistance, LDL and high-density lipoprotein values, and highly significant differences in mean triglyceride values.

CONCLUSIONS

The positive effects of ACE inhibitor drugs, particularly on hypertriglyceridemia and insulin resistance, might bring them forth as first-line drugs in the treatment of obese and hypertensive children. Randomized, controlled, double-blind, and long-term studies are needed for a definitive conclusion.

Drug-induced hypoglycaemia: an update

Drugs are the most frequent cause of hypoglycaemia in adults. Although hypoglycaemia is a well known adverse effect of antidiabetic agents, it may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including NSAIDs, analgesics, antibacterials, antimalarials, antiarrhythmics, antidepressants and other miscellaneous agents. They induce hypoglycaemia by stimulating insulin release, reducing insulin clearance or interfering with glucose metabolism. Several drugs may also potentiate the hypoglycaemic effect of antidiabetic agents. Administration of these agents to individuals with diabetes mellitus is of most concern. Many of these drugs, and depending on clinical setting, may also induce hyperglycaemia. Drug-induced hepatotoxicity and nephrotoxicity may lead in certain circumstances to hypoglycaemia. Some drugs may also induce hypoglycaemia by causing pancreatitis. Drug-induced hypoglycaemia is usually mild but may be severe. Effective clinical management can be handled through awareness of this drug-induced adverse effect on blood glucose levels. Herein, we review pertinent clinical information on the incidence of drug-induced hypoglycaemia and discuss the underlying pathophysiological mechanisms, and prevention and management.

Characteristics of patients with sulphonurea-induced hypoglycemia

BACKGROUND/AIM

Sulphonylurea (SU) agents continue to be a cornerstone of the therapy of type 2 diabetes mellitus (T2DM). Hypoglycemia is the most dangerous side effect of SU. Identifying the characteristics of patients with SU-induced hypoglycemia (SUIH) may help in reducing its frequency.

METHODS

All consecutive admissions of patients with SUIH, between 2000 and 2008, were retrospectively reviewed.

RESULTS

Over the study period, 4702 patients with type 2 diabetes mellitus were admitted to the department of medicine. Of these, 155 patients were admitted because of SUIH. Most of these patients were elderly, had multiple comorbid situations, and were taking multiple medications. Almost a third of the patients had a history of recent changes in the use of their medications. Various infectious complications (urinary, lung, skin, and peritoneal) occurred in 43% of patients. Renal failure was a frequent finding at admission (44% of patients had creatinine plasma levels > 120 μmol/L). Poor oral intake before admission was reported by 31% of patients. Markers of malnutrition (low serum levels of albumin, iron, vitamin B-12, and folic acid) were frequently found in most patients. Mean hemoglobin A1C levels were in the low abnormal levels. A major vascular event during hospitalization co-occurred in 11% of patients. Three patients died during the hospital admission for SUIH.

CONCLUSIONS

Elderly fragile patients with multiple comorbid situations including renal failure and tight glycemic control are prone to develop SUIH. Sulphonylurea agents should be avoided in such patients. An episode of SUIH should be considered as an alarming prognostic marker.

Stratified analyses for selecting appropriate target patients with diabetic peripheral neuropathy for long-term treatment with an aldose reductase inhibitor, epalrestat

AIMS

The long-term efficacy of epalrestat, an aldose reductase inhibitor, in improving subjective symptoms and nerve function was comprehensively assessed to identify patients with diabetic peripheral neuropathy who responded to epalrestat treatment.

METHODS

Stratified analyses were conducted on data from patients in the Aldose Reductase Inhibitor-Diabetes Complications Trial (ADCT). The ADCT included patients with diabetic peripheral neuropathy, median motor nerve conduction velocity > or = 40 m/s and with glycated haemoglobin (HbA(1c)) < or = 9.0%. Longitudinal data on HbA(1c) and subjective symptoms of the patients for 3 years were analysed (epalrestat n = 231, control subjects n = 273). Stratified analyses based on background variables (glycaemic control, grades of retinopathy or proteinuria) were performed to examine the relationship between subjective symptoms and nerve function. Multiple logistic regression analyses were conducted.

RESULTS

Stratified subgroup analyses revealed significantly better efficacy of epalrestat in patients with good glycaemic control and less severe diabetic complications. In the control group, no improvement in nerve function was seen regardless of whether symptomatic benefit was obtained. In the epalrestat group, nerve function deteriorated less or improved in patients whose symptoms improved. The odds ratio of the efficacy of epalrestat vs. control subjects was approximately 2 : 1 (4 : 1 in patients with HbA(1c) < or = 7.0%).

CONCLUSION

Our results suggest that epalrestat, an aldose reductase inhibitor, will provide a clinically significant means of preventing and treating diabetic neuropathy if used in appropriate patients.

A signal of increased risk of hypoglycaemia with angiotensin receptor blockers caused by confounding

AIMS

To study reporting of hypoglycaemia in angiotensin receptor blocker (ARB) users, and to investigate the possibility of confounding.

METHODS

The French pharmacovigilance database was examined for an association between hypoglycaemia and ARBs or other drugs using reports notified between 1996 and 2005. This association was also tested in patients taking or not taking antidiabetic agents (ADAs) using reporting odds ratios (ROR).

RESULTS

Hypoglycaemia was mentioned in 807 of the 174 595 reports entered during the study period. Overall hypoglycaemia was associated with the use of ARBs [ROR 2, 95% confidence interval (CI) 1, 3] and with the use of ADAs (ROR 32, 95% CI 27, 37). Moreover, the use of ARBs was associated with the use of ADAs (OR 7, 95% CI 6, 8). Considering separately reports with and without ADA, the association of ARB use with a higher risk of hypoglycaemia disappeared (OR 0.4, 95% CI 0.2, 0.8 and OR 2, 95% CI 1, 3, respectively).

CONCLUSION

A signal indicating an association between ARB use and hypoglycaemia was found in the French pharmacovigilance database. This signal disappeared after stratification on ADA use, thus suggesting confounding by indication. Moreover, the association between ARB use and hypoglycaemia was negative in ADA users.

Blocking the renin-angiotensin-aldosterone system to prevent diabetes mellitus

Type 2 diabetes mellitus (DM) is increasing around the world, and the public health impact of DM, driven largely by cardiovascular disease complications, underpins the importance of continued efforts toward primary prevention of DM. Only a few interventions have been shown to prevent DM, with none of them yet proven to improve cardiovascular risk commensurately. Accumulating evidence suggest that drugs that block the renin-angiotensin-aldosterone system (RAAS), many of which have proven cardiovascular disease (CVD) benefit, also have favourable effects on parameters of glucose metabolism and incident diabetes. Here we review the evidence accumulated to date from animal studies, clinical mechanistic studies and clinical trials regarding the effect of RAAS inhibition and incident DM.

Enhancement of blood glucose lowering effect of a sulfonylurea when coadministered with an ACE inhibitor: results of a glucose-clamp study

BACKGROUND

To investigate if coadministration of enalapril alters the metabolic effect of glibenclamide by employing an euglycemic glucose-clamp technique in healthy volunteers.

METHODS

A double-blind crossover study with nine healthy normotensive volunteers (age 27 +/- 3 y, BMI 23.3 +/- 2.0 kg m(-2); mean +/- SD)-randomly assigned to a 3-day treatment of either 5 mg enalapril or placebo. In the morning of the fourth day, volunteers orally received 3.5 mg glibenclamide together with either 10 mg enalapril or placebo. Blood glucose levels of volunteers were allowed to fall by 10% from fasting levels and were kept constant thereafter by employing a Biostator-based euglycemic glucose clamp.

RESULTS

Coadministration of enalapril-compared with placebo-resulted in a temporarily higher metabolic effect of glibenclamide (AUC GIR(0-120)229 +/- 173 vs 137 +/- 44 mg kg(-1), p < 0.01; mean +/- SD), which lasted from 120 min to 240 min after enalapril administration. In parallel, the maximal metabolic effect of glibenclamide tended to be higher with enalapril (GIR(max)5.2 +/- 1.9 vs 4.1 +/- 1.3 mg kg(-1) min(-1); p = 0.19). However, the total metabolic effect of glibenclamide was almost identical between volunteers taking enalapril or placebo (AUC GIR(0-600)1267 +/- 334 vs 1286 +/- 249 mg kg(-1), ns). In contrast, serum insulin levels, C-peptide levels, and serum glibenclamide profiles were not significantly different between enalapril and placebo.

CONCLUSIONS

The results of this study may explain the higher incidence of hypoglycemic episodes observed in patients with type 2 diabetes when taking ACE inhibitors together with sulfonylureas or insulin. ACE inhibitors may cause a temporary increase of the insulin sensitivity, which leads to an increased risk of hypoglycemia under these conditions.

Can continuous glucose monitoring provide objective documentation of hypoglycemia unawareness?

OBJECTIVE

To establish criteria defining hypoglycemia as detected by the continuous glucose monitoring system (CGMS) in patients with type 1 diabetes that best predict hypoglycemia unawareness (HUN), established by a validated questionnaire.

METHODS

Adult patients were selected for inclusion in this study if they had long-standing type 1 diabetes, a fasting level of C peptide of < or = 0.6 ng/mL, commitment to achieving glycemic control, and a hemoglobin A1c value no higher than 9%. After clinical data and self-monitoring of plasma glucose data were collected, patients underwent a 72-hour glucose monitoring session with use of a Medtronic-MiniMed CGMS. The presence of HUN was determined by a questionnaire. Factors independently associated with HUN were estimated by multivariate independent analysis.

RESULTS

Our study group consisted of 60 patients (33 women and 27 men) who ranged in age from 18 to 84 years (mean, 50.4) and had had diabetes for 5 to 56 years (mean, 23.8). The best predictor of HUN was the maximal duration of hypoglycemia, as determined by the CGMS (P = 0.001). Detection of hypoglycemic episodes with a duration of more than 90 minutes identified patients who had HUN with an 88% specificity and 75% sensitivity. HUN was also significantly associated with use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (P = 0.003) and with a longer duration of diabetes (P = 0.008).

CONCLUSION

The CGMS can be used for objective detection of patients with HUN.

Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system

Type 2 diabetes mellitus is becoming a major health problem associated with excess morbidity and mortality. As the prevalence of type 2 diabetes is rapidly increasing, prevention of the disease should be considered as a key objective in the near future. Besides lifestyle changes, various pharmacological treatments have proven their efficacy in placebo-controlled clinical trials, including antidiabetic drugs such as metformin, acarbose and troglitazone, or antiobesity agents such as orlistat. Arterial hypertension, a clinical entity in which insulin resistance is common, is strongly associated with type 2 diabetes and may precede the disease by several years. While antihypertensive agents such as diuretics or beta-adrenoceptor antagonists may worsen insulin resistance and impair glucose tolerance, newer antihypertensive agents exert neutral or even slightly positive metabolic effects. Numerous clinical trials have investigated the effects of ACE inhibitors or angiotensin II receptor antagonists (ARAs) on insulin sensitivity in hypertensive patients, with or without diabetes, with no consistent results. Almost half of the studies with ACE inhibitors in hypertensive nondiabetic individuals demonstrated a slight but significant increase in insulin sensitivity as assessed by insulin-stimulated glucose disposal during a euglycaemic hyperinsulinaemic clamp, while the other half failed to reveal any significant change. The effects of ARAs on insulin sensitivity are neutral in most studies. Mechanisms of improvement of glucose tolerance and insulin sensitivity through the inhibition of the renin-angiotensin system (RAS) are complex. They may include improvement of blood flow and microcirculation in skeletal muscles and, thereby, enhancement of insulin and glucose delivery to the insulin-sensitive tissues, facilitating insulin signalling at the cellular level and improvement of insulin secretion by the beta cells. Six recent large-scale clinical studies reported a remarkably consistent reduction in the incidence of type 2 diabetes in hypertensive patients treated with either ACE inhibitors or ARAs for 3-6 years, compared with a thiazide diuretic, beta-adrenoceptor antagonist, the calcium channel antagonist amlodipine or even placebo. The relative risk reduction averaged 14% (p = 0.034) in the CAPPP (Captopril Prevention Project) with captopril compared with a thiazide or beta1-adrenoceptor antagonist, 34% (p < 0.001) in the HOPE (Heart Outcomes Prevention Evaluation) study with ramipril compared with placebo, 30% (p < 0.001) in the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) with lisinopril compared with chlortalidone, 25% (p < 0.001) in the LIFE (Losartan Intervention For Endpoint reduction in hypertension study) with losartan compared with atenolol, and 25% (p = 0.09) in the SCOPE (Study on Cognition and Prognosis in the Elderly) with candesartan cilexetil compared with placebo, and 23% (p < 0.0001) in the VALUE (Valsartan Antihypertensive Long-term Use Evaluation) trial with valsartan compared with amlodipine. All these studies considered the development of diabetes as a secondary endpoint, except the HOPE trial where it was a post hoc analysis. These encouraging observations led to the initiation of two large, prospective, placebo-controlled randomised clinical trials whose primary outcome is the prevention of type 2 diabetes: the DREAM (Diabetes REduction Approaches with ramipril and rosiglitazone Medications) trial with the ACE inhibitor ramipril and the NAVIGATOR (Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research) trial with the ARA valsartan. Finally, ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) will also investigate as a secondary endpoint whether it is possible to prevent the development of type 2 diabetes by blocking the RAS with either an ACE inhibitor or an ARA or a combination of both. Thus, the recent consistent observations of a 14-34% reduction of the development of diabetes in hypertensive patients receiving ACE inhibitors or ARAs are exciting. From a theoretical point of view, they emphasise that there are many aspects of the pathogenesis, prevention and treatment of type 2 diabetes that still need to be uncovered. From a practical point of view, they may offer a new strategy to reduce the ongoing epidemic and burden of type 2 diabetes.

Why blockade of the renin–angiotensin system reduces the incidence of new-onset diabetes

Recent trials have suggested that inhibitors of the renin-angiotensin system (RAS), such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), may reduce the incidence of new-onset diabetes in patients with or without hypertension and at high risk of developing diabetes. In this review, we critically evaluate the evidence from recent clinical trials for such a potential preventive effect of ACE inhibitors and ARBs, including a meta-analysis of these recent trials. The reduced incidence of diabetes in patients at high risk of developing diabetes by ACE inhibitors or ARBs has been explained by haemodynamic effects, such as improved delivery of insulin and glucose to the peripheral skeletal muscle, and non-haemodynamic effects, including direct effects on glucose transport and insulin signalling pathways, all of which decrease insulin resistance. There is now evidence that the pancreas may contain an in situ active RAS, which appears to be upregulated in an animal model of type 2 diabetes. Thus, ACE inhibitors and ARBs may act by attenuating the deleterious effect of angiotensin II on vasoconstriction, fibrosis, inflammation, apoptosis and beta-cell death in the pancreas, thereby protecting a critical beta-cell mass essential for insulin production. New evidence is presented that ACE inhibitors and ARBs may delay or prevent the development of insulin resistance and diabetes, for which novel mechanisms are suggested. The actions of agents that interrupt the RAS on insulin resistance, obesity and diabetes warrant further investigation in other animal models. Prospective clinical studies with the primary endpoint of the prevention of diabetes are now indicated to (i) further explore whether the inhibitors of the RAS are superior compared to other antihypertensive agents such as calcium channel blockers (CCBs) and (ii) to evaluate the potential beneficial effects of combination antihypertensive regimens on the development of diabetes.

The role of sulphonylureas in the management of type 2 diabetes mellitus

The sulphonylureas act by triggering insulin release from the pancreatic beta cell. A specific site on the adenosine triphosphate (ATP)-sensitive potassium channels is occupied by sulphonylureas leading to closure of the potassium channels and subsequent opening of calcium channels. This results in exocytosis of insulin. The meglitinides are not sulphonylureas but also occupy the sulphonylurea receptor unit coupled to the ATP-sensitive potassium channel. Glibenclamide (glyburide), gliclazide, glipizide and glimepiride are the primary sulphonylureas in current clinical use for type 2 diabetes mellitus. Glibenclamide has a higher frequency of hypoglycaemia than the other agents. With long-term use, there is a progressive decrease in the effectiveness of sulphonylureas. This loss of effect is the result of a reduction in insulin-producing capacity by the pancreatic beta cell and is also seen with other antihyperglycaemic agents. The major adverse effect of sulphonylureas is hypoglycaemia. There is a theoretical concern that sulphonylureas may affect cardiac potassium channels resulting in a diminished response to ischaemia. There are now many choices for initial therapy of type 2 diabetes in addition to sulphonylureas. Metformin and thiazolidinediones affect insulin sensitivity by independent mechanisms. Disaccharidase inhibitors reduce rapid carbohydrate absorption. No single agent appears capable of achieving target glucose levels in the majority of patients with type 2 diabetes. Combinations of agents are successful in lowering glycosylated haemoglobin levels more than with a single agent. Sulphonylureas are particularly beneficial when combined with agents such as metformin that decrease insulin resistance. Sulphonylureas can also be given with a basal insulin injection to provide enhanced endogenous insulin secretion after meals. Sulphonylureas will continue to be used both primarily and as part of combined therapy for most patients with type 2 diabetes.

Hospital hypoglycemia: not only treatment but also prevention

OBJECTIVE

To propose a strategy, applicable on general hospital wards, for prevention of hypoglycemia in hospitalized patients.

RESULTS

Although the mortality rate among hospitalized patients with hypoglycemia has been shown to be 22.2 to 27% in series that included patients with diabetes, some investigators have shown that hypoglycemia is not an independent predictor of mortality. Outside the critical care setting, the comparative risks of hyperglycemia and hypoglycemia and the relationship of hospital hypoglycemia to intensification of glycemic control have not been determined. The reported incidence of hospital hypoglycemia ranges from 1.2% for hospitalized adults to 20% for nonpregnant patients with diabetes admitted without a metabolic emergency. Among patients receiving antihyperglycemic therapy, the literature describes precipitating events--usually a sudden change of caloric exposure-- and predisposing conditions for hypoglycemic episodes.

CONCLUSION

Hospital hypoglycemia is predictable, and it is preventable by measures other than undertreatment of hyperglycemia. Physician orders for antihyperglycemic therapy should be written and, if necessary, be revised so as to respond to the presence of predisposing conditions for hypoglycemia. A ward-based protocol or hospital-wide policy should establish the appropriate response to triggering events. Within the time frame of action of previously administered antihyperglycemic drugs (after abrupt interruption of caloric exposure), the threshold for preventive intravenous administration of dextrose is a glucose concentration of 120 mg/dL.

A Systematic Approach to Managing Hypertension and the Metabolic Syndrome in Primary Care

OBJECTIVES

Obesity is driving a high prevalence of hypertension and metabolic syndrome-related risk and disease. This report summarizes the impact of a standardized, evidence-based approach to managing high blood pressure and associated metabolic syndrome abnormalities that was developed and implemented by one Clinical Hypertension Specialist.

METHODS

Longitudinal data on blood pressure, low-density lipoprotein cholesterol (LDL-C), hemoglobin A1c (HbA1c), cardiovascular and renal comorbidities, and treatment medications were obtained on all 817 hypertensive patients seen from January 1, 2000 to June 30, 2003.

RESULTS

The hypertensive patients were 72 +/- 11 (SD) years old, and more than 55% of them were high risk based on target organ damage, clinical cardiovascular disease, or diabetes mellitus. Blood pressure was < 140/90 mm Hg in 77% of all patients. Among the high-risk patients, mean blood pressure was 126 +/- 14/71 +/- 10 on 2.8 +/- 1.4 antihypertensive medications, with 88% on angiotensin converting enzyme inhibitors or angiotensin receptor blockers, 59% on diuretics, 49% on calcium channel blockers, and 36% on beta-blockers. Among dyslipidemic hypertensives, LDL-C was controlled to < 130 mg/dL in 84% (510/605) overall and to < 100 mg/dL in 70% of the high-risk group (299/427). Among diabetic hypertensives, the mean HbA1c was 6.8%, with 64% (155/242) less than 7%. New patients demonstrated improved blood pressure, LDL-C, and hemoglobin A1c control over time as the management algorithm was applied.

CONCLUSIONS

A high prevalence of complicated hypertension was documented. Blood pressure, LDL-C, and HbA1c were controlled to goal in a high proportion of patients. The findings demonstrate that application of an evidence-based management algorithm can facilitate higher rates of cardiovascular risk factor control than are generally reported in primary care practices.

Cost-effective strategies in the prevention of diabetic nephropathy

A significant subgroup of patients with diabetes mellitus are predisposed to developing diabetic nephropathy and it is in this subgroup that other diabetes- related complications, and in particular greatly increased cardiovascular disease risk, are concentrated. The high personal, social and financial costs of managing end-stage renal failure and the other complications associated with diabetic nephropathy make a powerful case for screening and effective intervention programmes to prevent the condition or retard its progression. As major breakthroughs in finding genetic susceptibility factors remain elusive, screening efforts continue to be based on microalbuminuria testing, despite increasing recognition of its limitations as a positive predictor of nephropathy. Interventions have been extensively studied, but results remain conflicting. Economic evaluations of such screening and intervention programmes are essential for health planners, yet models of the cost/benefit ratio of such interventions often rely on a rather slim evidence base. Where economic models are developed, they are frequently based on those papers that propound the greatest clinical benefits of a given intervention, leading to a possible over-estimation of the advantages of the chosen approach. Furthermore, the benefits of even such generally accepted interventions as ACE inhibitor treatment are less firmly established than generally appreciated. Lifestyle interventions are instinctively attractive, but are by no means a low-cost option (as is often assumed by both medical professionals and politicians). This review critically assesses the evidence for clinical efficacy and economic benefit of microalbuminuria screening and interventions such as intensive glycaemic control, antihypertensive treatment, ACE inhibition and angiotensin receptor blockade, dietary protein restriction and lipid-modifying therapy. The various costs associated with diabetic nephropathy are so great that even expensive interventions may have a favourable cost/benefit ratio, provided they are truly effective.

Mechanisms by which angiotensin-converting enzyme inhibitors prevent diabetes and cardiovascular disease

Angiotensin-converting enzyme (ACE) inhibitors are the first-line therapeutic agents for treating hypertension in patients with the cardiometabolic syndrome and those with diabetes. ACE inhibitor therapy reduces both microvascular and macrovascular complications in diabetes and appears to improve insulin sensitivity and glucose metabolism. Several recent studies indicate that ACE inhibitor therapy reduces the development of type 2 diabetes in persons with essential hypertension, a population with a high prevalence of insulin resistance. ACE inhibitor therapy has been shown to improve surrogates of cardiovascular disease (eg, vascular compliance, endothelial-derived nitric oxide production, vascular relaxation and plasma markers of inflammation, oxidative stress, and thrombosis) and reduce cardiovascular disease, renal disease progression, and stroke. This article explores potential mechanism by which ACE inhibition reduces the development of diabetes, improves these surrogate markers, and reduces cardiovascular disease and renal disease.

Analysis of metabolic parameters as predictors of risk in the RENAAL study

OBJECTIVE

Metabolic factors such as glycemic control, hyperlipidemia, and hyperkalemia are important considerations in the treatment of patients with type 2 diabetes and nephropathy. In the RENAAL (Reduction of End Points in Type 2 Diabetes With the Angiotensin II Antagonist Losartan) study, losartan reduced renal outcomes in the patient population. This post hoc analysis of the RENAAL study reports the effects of losartan on selected metabolic parameters and assesses the relationship between baseline values of metabolic parameters and the primary composite end point or end-stage renal disease (ESRD).

RESEARCH DESIGN AND METHODS

Glycemic control (HbA(1c)) and serum lipid, uric acid, and potassium levels were compared between the losartan and placebo groups over time, and baseline levels were correlated with the risk of reaching the primary composite end point (doubling of serum creatinine, ESRD, or death) or ESRD alone.

RESULTS

Losartan did not adversely affect glycemic control or serum lipid levels. Losartan-treated patients had lower total (227.4 vs. 195.4 mg/dl) and LDL (142.2 vs. 111.7 mg/dl) cholesterol. Losartan was associated with a mean increase of up to 0.3 mEq/l in serum potassium levels; however, the rate of hyperkalemia-related discontinuation was similar between the placebo and losartan groups. Univariate analysis revealed that baseline total and LDL cholesterol and triglyceride levels were associated with increased risk of developing the primary composite end point. Similarly, total and LDL cholesterol were also associated with increased risk of developing ESRD.

CONCLUSIONS

Overall, losartan was well tolerated by patients with type 2 diabetes and nephropathy and was associated with a favorable effect on the metabolic profile of this population.

Influence of captopril on symptomatic and hormonal responses to hypoglycaemia in humans

AIMS

Hypoglycaemic symptoms and hormonal counter-regulation are of high importance to avoid the risk of severe hypoglycaemia in patients with diabetes mellitus. Various antihypertensive drugs, such as angiotensin-converting enzyme (ACE) inhibitors, have been suspected for a long time to reduce this response to hypoglycaemia in diabetic subjects. Although ACE inhibitors are approved for controlling diabetic complications, previous investigations regarding this putative side-effect are controversial.

METHODS

We performed clamp experiments in 16 healthy men lasting for 6 h each. The subjects were pretreated for 7 days with captopril 3 x 25 mg day-1 vs placebo in a randomized, double-blind, crossover study. Plasma glucose was decreased in a stepwise manner during a hypoglycaemic clamp session and counter-regulatory hormones [epinephrine (adrenaline), norepinephrine (adrenaline), ACTH, cortisol, glucagon], symptoms, and haemodynamic parameters (blood pressure, heart rate] were measured.

RESULTS

Counter-regulatory hormone concentrations significantly increased in both sessions (ACE inhibitor vs placebo) during hypoglycaemia. The rise of counter-regulatory hormones as well as symptom scores were equal under both ACE inhibitor and placebo treatment. Systolic blood pressure and heart rate increased (from 110 +/- 3 vs 115 +/- 3 mmHg to 132 +/- 4 vs 133 +/- 4 mmHg) whereas diastolic blood pressure slightly decreased (from 63 +/- 2 vs 70 +/- 3 mmHg to 61 +/- 2 vs 64 +/- 2 mmHg) independent of pretreatment. Systolic and diastolic blood pressure were significantly lower in the captopril session vs placebo (P < 0.05).

CONCLUSIONS

Our results demonstrate that subchronic treatment with captopril does not attenuate symptomatic and hormonal response to hypoglycaemia. Thus, to patients at risk of hypoglycaemia who require antihypertensive or nephroprotective treatment, we would continue giving an ACE inhibitor.

Role of ACE inhibitors in treating hypertensive diabetic patients

Cardiovascular disease (CVD) is a major determining factor of morbidity and mortality in type 2 diabetic patients. Hypertension, which accompanies diabetes in more than 70% of cases, contributes to increased prevalence of CVD events in this group of patients. Results from the United Kingdom Prospective Diabetes Study (UKPDS) indicated that reduction of elevated blood pressure might decrease CVD morbidity and mortality more than reduction of hyperglycemia. Activation of circulating and tissue renin-angiotensin system (RAS) contributes to the development of both hypertension and insulin resistance in patients with the cardiometabolic syndrome. Angiotensin-converting enzyme (ACE) inhibitor therapy in patients with the cardiometabolic syndrome may improve insulin action as well as lessen CVD. In clinical trials, ACE inhibitors have been shown to be more efficient than other antihypertensive medications (i.e., calcium channel blockers) in the reduction of CVD morbidity and mortality in hypertensive diabetics. In this article, we summarize possible mechanisms by which ACE inhibition may improve insulin resistance, coagulation/clotting, and vascular function abnormalities, and postpone or even prevent the development of type 2 diabetes in hypertensive patients.

The use of ACE inhibitors on diabetic patients without renal disease

Strategies that interrupt the renin-angiotensin system, especially with angiotensin-converting enzyme (ACE) inhibition, reduce cardiovascular disease mortality and morbidity in high-risk persons such as those with the insulin resistance syndrome and diabetes mellitus. In the 1980s emphasis was placed on the renal protective effects of ACE inhibitors in patients with diabetes and proteinuria. During the past several years controlled clinical trials have demonstrated that ACE inhibition reduces cardiovascular disease (CVD) mortality and morbidity. This is especially important in patients in the United States, where 80% of excess mortality for diabetes mellitus is attributed to CVD. This article reviews the clinical trials in high-risk patients, especially those with diabetes, that shown beneficial CVD risk reduction with ACE inhibitors.

Beta-blockers in the management of hypertension in patients with type 2 diabetes mellitus: is there a role?

It has been conclusively established that treatment of hypertension in patients with type 2 (non-insulin-dependent) diabetes mellitus will significantly reduce the incidence of stroke, heart failure and progression of diabetic complications. Beta-blockers are effective antihypertensive agents which, in long term studies, have proven beneficial in reducing important clinical end-points. However nonselective beta-blockers may have a negative effect on lipid profiles and contribute to hypoglycaemic unawareness, thus preventing their use in some patients with diabetes mellitus. The development of newer and more selective beta-blockers has overcome many of these problems. In addition, some of the newer agents have novel properties such as release of nitric oxide, which theoretically would make them more attractive in patients with diabetes mellitus. Overall, the adverse metabolic effects of beta-blockers do not appear to be important in clinical practice and these agents should no longer be contraindicated in patients with type 2 diabetes mellitus. Their proven cardiovascular benefits would seem to easily tip the balance in favour of their use.

Betablocker treatment in diabetes mellitus

OBJECTIVES

Betablockers have been convincingly shown to reduce total and cardiovascular morbidity and mortality of hypertensive diabetic patients. In diabetic patients, after myocardial infarction, these agents confer a twice as high protective effect when compared to non-diabetic patients. However, most paradoxically, betablocking agents are used less frequently in diabetes. Control of hypertension is insufficient in most of the diabetic patients, probably because a combination of antihypertensive agents including betablockers is frequently needed to sufficiently control blood pressure but is not used in these patients. The fear of betablocker-associated side effects in diabetes may be partly responsible for the frequent antihypertensive mono-therapy and the resulting poor quality of blood pressure control among diabetic patients.

DESIGN

We have performed an analysis of the literature to assess whether possible adverse metabolic effects, a higher risk of hypoglycaemia or less nephroprotective effects of beta1-selective betablocking agents could justify the reticence in prescribing these antihypertensive agents to diabetic patients.

RESULTS

A thorough review of the literature does not indicate that beta1-selective betablocking agents have important adverse effects on glucose metabolism, prolong hypoglycaemia or mask hypoglycaemic symptoms. In diabetic nephropathy, betablockers are as nephroprotective as angiotensin converting enzyme inhibitors.

CONCLUSIONS

The unnecessary less frequent prescription of beta1-selective betablockers in diabetes mellitus may contribute to the higher cardiovascular mortality among these patients.

Diabetes mellitus and diabetes-associated vascular disease

Diabetes-related cardiovascular disease remains the leading cause of death in patients with type 2 diabetes. Hypertension is common among diabetics and has the same pathogenetic mechanisms as insulin resistance, in which the activated renin-angiotensin system contributes to the emerging high blood pressure and hyperglycemia. Hyperglycemia is one of the triggering factors for vascular dysfunction and clotting abnormalities and, therefore, for accelerated atherosclerosis in diabetes. Glycated hemoglobin levels, as a reflection of the degree of glycemia, are strongly associated with the risk of cardiovascular disease in diabetics and in the general population. Tight glycemic control, the treatment of dyslipidemia and raised blood pressure, in addition to the use of antiplatelet therapy, all powerfully reduce the risks associated with diabetes. Furthermore, angiotensin-converting enzyme inhibitors might offer additional cardioprotection to diabetics above that provided by blood pressure reduction.