Association between hyper- and hypoglycaemia and 2 year all-cause mortality risk in diabetic patients with acute coronary events

Insulin as an anti-inflammatory and antiatherogenic modulator

Data demonstrate the anti-inflammatory effects of insulin and proinflammatory effects of glucose. These data provide a mechanistic justification for the benefits of maintaining euglycemia with insulin infusions in hospitalized patients. Regimens that infuse fixed doses of insulin with high rates of glucose are usually associated with hyperglycemia, which may neutralize the beneficial effects of insulin. Therefore, we propose that such regimens should be avoided and instead replaced by insulin infusions that normalize and maintain blood glucose at a reasonably low level and ensure that plasma insulin is maintained at levels high enough to provide clinically relevant anti-inflammatory and cardioprotective effects. Trials to test this hypothesis are in progress.

Impaired insulin signaling accelerates cardiac mitochondrial dysfunction after myocardial infarction

Diabetes increases mortality and accelerates left ventricular (LV) dysfunction following myocardial infarction (MI). This study sought to determine the impact of impaired myocardial insulin signaling, in the absence of diabetes, on the development of LV dysfunction following MI. Mice with cardiomyocyte-restricted knock out of the insulin receptor (CIRKO) and wildtype (WT) mice were subjected to proximal left coronary artery ligation (MI) and followed for 14 days. Despite equivalent infarct size, mortality was increased in CIRKO-MI vs. WT-MI mice (68% vs. 40%, respectively). In surviving mice, LV ejection fraction and dP/dt were reduced by >40% in CIRKO-MI vs. WT-MI. Relative to shams, isometric developed tension in LV papillary muscles increased in WT-MI but not in CIRKO-MI. Time to peak tension and relaxation times were prolonged in CIRKO-MI vs. WT-MI suggesting impaired, load-independent myocardial contractile function. To elucidate mechanisms for impaired LV contractility, mitochondrial function was examined in permeabilized cardiac fibers. Whereas maximal ADP-stimulated mitochondrial O(2) consumption rates (V(ADP)) with palmitoyl carnitine were unchanged in WT-MI mice relative to sham-operated animals, V(ADP) was significantly reduced in CIRKO-MI (13.17+/-0.94 vs. 9.14+/-0.88 nmol O(2)/min/mgdw, p<0.05). Relative to WT-MI, expression levels of GLUT4, PPAR-alpha, SERCA2, and the FA-Oxidation genes MCAD, LCAD, CPT2 and the electron transfer flavoprotein ETFDH were repressed in CIRKO-MI. Thus reduced insulin action in cardiac myocytes accelerates post-MI LV dysfunction, due in part to a rapid decline in mitochondrial FA oxidative capacity, which combined with limited glucose transport capacity that may reduce substrate utilization and availability.

Association of fasting and post-prandial hyperglycemia on the risk of cardiovascular and all-cause death among non-diabetic Chinese

The role of post-prandial glucose on cardiovascular risk among Chinese adults without diabetes was investigated. In a median follow-up of 3.5 years on 16,590 participants, 95 cardiovascular deaths were found. The relative risk in the highest quintile post-prandial glucose was 1.61 (P for trend, 0.05) for cardiovascular death.

Fasting and postchallenge hyperglycemia and risk of cardiovascular disease in Chinese: the Chin-Shan Community Cardiovascular Cohort study

BACKGROUND

Whether fasting glucose is superior to postchallenge glucose or insulin level for prediction of cardiovascular disease (CVD) remains controversial. The aim of our study was to compare fasting, postchallenge glucose and other markers as predictors of CVD in a community-based prospective cohort study among 2,165 adult participants.

METHODS

A standard 75-g oral glucose tolerance test was performed, with measurements of fasting and 2-hour postchallenge plasma glucose and insulin levels. We defined the CVD outcome as incident coronary heart disease and stroke. Cox regression model was used to estimate the relative risk (RR) for CVD.

RESULTS

A total of 166 individuals developed major CVD events during 10.5 years of follow-up. Both fasting and postchallenge glucose were significantly associated with CVD risk (adjusted RR in the highest quartile vs the lowest quartile 1.74, 95% confidence interval [CI] 1.06-2.86 for fasting glucose; RR in highest quartile 2.05, 95% CI 1.23-3.42 for postchallenge glucose). Postchallenge and fasting glucose had similar areas of receiver operative characteristics curves (0.65, 95% CI 0.58-0.72 for postchallenge glucose; 0.65, 95% CI 0.58-0.72 for fasting glucose). In mutually adjusted models, fasting and postchallenge glucose remained significant risk factors for CVD, whereas insulin resistance variables became nonsigificant.

CONCLUSIONS

These findings show that fasting and postchallenge glucose concentrations are independent predictors of CVD risk among ethnic Chinese in Taiwan.

Insulin therapy in acute coronary syndromes: an appraisal of completed and ongoing randomised trials with important clinical end points

Insulin therapy was first proposed as an adjunctive therapy in patients with acute coronary syndromes (ACS) in the 1960s. Since then, numerous randomised clinical trials have been conducted to determine the efficacy and to define the role of insulin therapy in ACS. This review will discuss: 1) completed trials of insulin therapy in ACS, including both glucose-insulin-potassium (GIK) approaches and non-GIK approaches; 2) trials of insulin therapy in critically ill non-ACS patients and the lessons from these trials that can be applied to trials of insulin in ACS patients; and 3) a summary of ongoing and planned trials of insulin in ACS patients.

Blood glucose and its prognostic implications in patients hospitalised with acute myocardial infarction

Elevated blood glucose and its potential link with adverse outcomes in patients with acute myocardial infarction (AMI) has been the subject of intense study over more than 40 years. The numerous observational studies performed to date have addressed some of the questions in this field, but many critically important questions are still poorly understood, and remain subjects of debate. This review summarises current epidemiological data on the prevalence of hyperglycaemia in the AMI patient population and its relationship to patient outcomes, and addresses some of the existing controversies in the field.

Cardiometabolic risk management in type 2 diabetes and obesity

Type 2 diabetes has become an epidemic in the United States, mainly due to an increase in obesity and sedentary lifestyle. Diabetes is considered a cardiovascular risk equivalent, and cardiovascular death remains the most common cause of death in this population. The cardiovascular complications of diabetes, beginning as early as 10 years before the development of frank hyperglycemia, are strongly linked to the development of insulin resistance and the ensuing metabolic disarray often referred to as the metabolic syndrome. To provide proper therapy for cardiovascular prevention, the downstream effects of insulin resistance must be understood. The most important aspect of treating patients with the metabolic syndrome is the realization that treatment must begin before the development of frank hyperglycemia, particularly if cardiovascular events are to be avoided. Thus, in addition to managing the hyperglycemia that develops with the onset of diabetes, insulin resistance, dyslipidemia, and hypertension must also be properly addressed.

Special commentary: a call for intensive metabolic support

PURPOSE OF REVIEW

This special commentary addresses recent clinical reviews regarding appropriate nutrition and metabolic support in the critical care setting.

RECENT FINDINGS

There are divergent approaches between North America and Europe for the use of early nutrition support and combined enteral nutrition and parenteral nutrition support possibly due to the commercial availability of specific parenteral nutrients. The advent of intensive insulin therapy has changed the landscape of metabolic support in the intensive care unit, and previous notions about infective risk of parenteral nutrition will need to be re-addressed. Patients with brain failure may benefit from an intensive insulin therapy with a blood glucose target that is higher than that used in patients without brain failure. Patients with heart failure may benefit from the addition of nutritional pharmacology that targets proximate oxidative pathophysiological pathways. Intradialytic parenteral nutrition may be viewed as another form of supplemental parenteral nutrition when enteral nutrition is insufficient in patients on hemodialysis in the intensive care unit.

SUMMARY

It is proposed that intensive metabolic support be routinely implemented in the intensive care unit based on the following steps: intensive insulin therapy with an appropriate blood glucose target, nutrition risk assessment, early and if needed combined enteral nutrition and parenteral nutrition to target 20-25 kcal/kg/day and 1.2-1.5 g protein/kg/day, and nutritional and metabolic monitoring.

Hyperglycemia and outcome in the pediatric intensive care unit

OBJECTIVE

To identify the frequency of hyperglycemia in children who are nondiabetic and critically ill and assess the independent effect of hyperglycemia on outcome.

STUDY DESIGN

Consecutive admissions to the pediatric intensive care unit (PICU) were reviewed. The Pediatric Risk of Mortality III score (PRISM) measured patient acuity. Because maximum glucose level in the first day of PICU admission (GLFD) >200mg/dL contributes to PRISM, 200 mg/dL was used to differentiate high glucose (HG) from normal glucose.

RESULTS

Of 1550 patients, 221 (14.3%) had HG. GLFD correlated with PRISM (r = 0.39, P < .001). Without controlling for PRISM, the HG group had more mechanical ventilation days (MVD; P < .001), longer PICU length of stay (PLOS; P < .001) and lower percent survival (P < .001) than the normal glucose group. Controlling for PRISM in survivors, GLFD was not associated with PLOS (P = .75) or with MVD (P = .06). GLFD was not significantly associated with survival (P = .76). In nonsurvivors, GLFD was not associated with PLOS (P = .19) or MVD (P = .31).

CONCLUSION

When controlling for disease severity, hyperglycemia within 24 hours of PICU admission was not independently associated with increased mechanical ventilation time, length of stay, or mortality. Prospective evaluation of glycemic control in critically ill children is needed to elucidate its effects on outcome.

[The impact of diabetes mellitus on the mortality of acute coronary syndromes]

Diabetes mellitus (DM) is a leading cause of mortality in the world, mainly on account of cardiovascular diseases. At present we know that not only DM but also other hyperglycemic states are a risk factor for coronary arterial disease. In the context of acute coronary syndromes, DM determines a worst prognosis, either in short- or long-term outcomes. Since the absolute risk of death is greater among diabetic patients when compared to non-diabetic patients, therapeutical interventions have a greater impact in terms of benefits to these patients as well. Strategies such as strict control of hyperglycemia during hospitalization, acute reperfusion management (either by thrombolysis or by percutaneous coronary intervention), use of platelet glycoprotein IIb/IIIa inhibitors and angiotensin-converting enzyme (ACE)-inhibitors have recently proven to be of greater benefit for diabetics over non-diabetic patients. Meanwhile, in spite of all proven benefits of the use of evidence-based interventions to the treatment of acute coronary syndromes on diabetic patients, there is still an under utilization of these measures. Therefore, taking into account the predictions of an increasing number of diabetics in the world for the future years, and the fact that acute coronary syndromes will be the leading cause of death among them, it becomes increasingly necessary for both cardiologists and endocrinologists to work together in order to reduce the unfavorable outcomes that are expected to arise.

Vascular disease and diabetes: is hypoglycaemia an aggravating factor?

Acute hypoglycaemia provokes profound physiological changes affecting the cardiovascular system and several haematological parameters, principally as a consequence of sympatho-adrenal activation and counter-regulatory hormonal secretion. Many of these responses have an important role in protecting the brain from neuroglycopenia, through altering regional blood flow and promoting metabolic changes that will restore blood glucose to normal. In healthy young adults the cardiovascular effects are transient and have no obvious detrimental consequences. However, some of the effected changes are potentially pathophysiological and in people with diabetes who have developed endothelial dysfunction, they may have an adverse impact on a vasculature that is already damaged. The acute haemodynamic and haematological changes may increase the risk of localized tissue ischaemia, and major vascular events can certainly be precipitated by acute hypoglycaemia. These include myocardial and cerebral ischaemia and occasionally infarction. Established diabetic retinopathy often deteriorates after strict glycaemic control is instituted, the latter being associated with a threefold increase in frequency of severe hypoglycaemia, and enhanced exposure to mild hypoglycaemia. The possible mechanisms underlying these hypoglycaemia-induced effects include haemorrheological changes, white cell activation, vasoconstriction, and the release of inflammatory mediators and cytokines. The concept that acute hypoglycaemia could aggravate vascular complications associated with diabetes is discussed in relation to evolving comprehension of the pathogenesis of atherosclerosis and blood vessel disease.

Effect of perioperative insulin infusion on surgical morbidity and mortality: systematic review and meta-analysis of randomized trials.7

OBJECTIVE

To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of perioperative insulin infusion on outcomes important to patients.

PATIENTS AND METHODS

We used 6 search strategies including an electronic database search of MEDLINE, EMBASE, and Cochrane CENTRAL, from their inception up to May 1, 2006, and included RCTs of perioperative insulin infusion (with or without glucose targets) measuring outcomes in patients undergoing any surgery. Pairs of reviewers working independently assessed the methodological quality and characteristics of included trials and abstracted data on perioperative outcomes (ie, outcomes that occurred during hospitalization or within 30 days of surgery).

RESULTS

We identified 34 eligible trials. In the 14 trials that assessed mortality, there were 68 deaths among 2192 patients randomized to insulin infusion compared with 98 deaths among 2163 patients randomized to control therapy (random-effects pooled relative risk, 0.69; 95% confidence interval [CI], 0.51-0.94; 99% CI, 0.46-1.04; I2, 0%; 95% CI, 0.0%-47.4%). Hypoglycemia increased in the intensively treated group (20 trials, 119/1470 patients in insulin infusion vs 48/1476 patients in control group; relative risk, 2.07; 95% CI, 1.29-3.32; 99% CI, 1.09-3.88; I2, 31.5%; 95% CI, 0.0%-59.0%). No significant effect was seen in any other outcomes. The available mortality data represent only 40% of the optimal information size required to reliably detect a plausible treatment effect; potential methodological and reporting biases weaken inferences.

CONCLUSION

Perioperative insulin infusion may reduce mortality but increases hypoglycemia in patients who are undergoing surgery; however, mortality results require confirmation in large and rigorous RCTs.

Use of insulin to improve glycemic control in diabetes mellitus

BACKGROUND

The restoration of normoglycemia ensures the control of diabetic symptoms and reduction in microangiopathic complications in type 1 and type 2 diabetes. However, there is no conclusive evidence that intensive glycemic control alone will prevent macrovascular disease, the commonest cause of morbidity and mortality in type 2 diabetes. As atherosclerosis is an inflammatory condition, it is relevant that the two common insulin resistant states of obesity and type 2 diabetes have significant inflammatory processes, which promote atherosclerosis. It is also relevant that glucose has been shown to have profound effects on the endothelial cell, the leukocyte and the platelet. These effects include the induction of acute oxidative and inflammatory stress and a prothrombotic and pro-apoptotic effect following glucose intake. In contrast insulin has been shown to exert several biological effects at physiologically relevant concentrations, in relation to the endothelial cell, the platelet and leucocyte function, which may be cardioprotective and potentially anti-atherosclerotic.

CONCLUSION

These findings are of great interest as it is possible that the prevention of macrovascular complications in type 2 diabetes may require the use of those glucose lowering drugs which have additional anti-inflammatory effects in addition to the control of comorbid conditions (hypertension and dyslipidemia) associated with this disease. Results of future clinical trials are awaited to confirm the benefits of this approach in the primary and secondary prevention of macrovascular complications in type 2 diabetes.

Hyperglycemia and acute coronary syndrome: a scientific statement from the American Heart Association Diabetes Committee of the Council on Nutrition, Physical Activity, and Metabolism

Hyperglycemia is common and associated with markedly increased mortality rates in patients hospitalized with acute coronary syndromes (ACS). Despite the fact that several studies have documented this association, hyperglycemia remains underappreciated as a risk factor, and it is frequently untreated in ACS patients. This is in large part due to limitations of prior studies, and the remaining critical gaps in our understanding of the relationship between hyperglycemia and poor outcomes. The main objective of the present statement is to summarize the current state of knowledge regarding the association between elevated glucose and patient outcomes in ACS and to outline the most important knowledge gaps in this field. These gaps include the need to specifically define hyperglycemia, develop optimal ways of measuring and tracking glucose values during ACS hospitalization, and better understand the physiological mechanisms responsible for poor outcomes associated with hyperglycemia. The most important issue, however, is whether elevated glucose is a direct mediator of adverse outcomes in ACS patients or just a marker of greater disease severity. Given the marked increase in short- and long-term mortality associated with hyperglycemia, there is an urgent need for definitive large randomized trials to determine whether treatment strategies aimed at glucose control will improve patient outcomes and to define specific glucose treatment targets. Although firm guidelines will need to await completion of these clinical trials, the present statement also provides consensus recommendations for hyperglycemia management in patients with ACS on the basis of the available data.

Glucometrics in patients hospitalized with acute myocardial infarction: defining the optimal outcomes-based measure of risk

BACKGROUND

Hyperglycemia on admission is associated with an increased mortality rate in patients with acute myocardial infarction. Whether metrics that incorporate multiple glucose assessments during acute myocardial infarction hospitalization are better predictors of mortality than admission glucose alone is not well defined.

METHODS AND RESULTS

We evaluated 16,871 acute myocardial infarction patients hospitalized from January 2000 to December 2005. Using logistic regression models and C indexes, 3 metrics of glucose control (mean glucose, time-averaged glucose, hyperglycemic index), each evaluated over 3 time windows (first 24 hours, 48 hours, entire hospitalization), were compared with admission glucose for their ability to discriminate hospitalization survivors from nonsurvivors. Models were then used to evaluate the relationship between mean glucose and in-hospital mortality. All average glucose metrics performed better than admission glucose. The ability of models to predict mortality improved as the time window increased (C indexes for admission, mean 24 hours, 48 hours, and hospitalization glucose were 0.62, 0.64, 0.66, 0.70; P<0.0001). Statistically significant but small differences in C indexes of mean glucose, time-averaged glucose, and hyperglycemic index were seen. Mortality rates increased with each 10-mg/dL rise in mean glucose > or = 120 mg/dL (odds ratio, 1.8; P=0.003 for glucose 120 to < 130 mg/dL) and with incremental decline < 70 mg/dL (odds ratio, 6.4; P=0.01 versus glucose 100 to < 110 mg/dL). The slope of these relationships was steeper in patients without diabetes.

CONCLUSIONS

Measures of persistent hyperglycemia during acute myocardial infarction are better predictors of mortality than admission glucose. Mean hospitalization glucose appears to be the most practical metric of hyperglycemia-associated risk. A J-shaped relationship exists between average glucose and mortality, with both persistent hyperglycemia and hypoglycemia associated with adverse prognosis.

Admission glycaemia and outcome in patients with acute coronary syndrome

Some studies of patients with acute myocardial infarction have reported that hyperglycaemia at admission may be associated with a worse outcome. This study sought to evaluate the association of blood glucose at admission with the outcome of unselected patients with acute coronary syndrome (ACS). Using the Acute Myocardial Infarction and unstable angina in Switzerland (AMIS Plus) registry, ACS patients were stratified according to their blood glucose on admission: group 1: 2.80-6.99 mmol/L, group 2: 7.00-11.09 mmol/L and group 3: > 11.10 mmol/L. Odds ratios for in-hospital mortality were calculated using logistic regression models. Of 2,786 patients, 73% were male and 21% were known to have diabetes. In-hospital mortality increased from 3% in group 1 to 7% in group 2 and to 15% in group 3. Higher glucose levels were associated with larger enzymatic infarct sizes (p<0.001) and had a weak negative correlation with angiographic or echographic left ventricular ejection fraction. High admission glycaemia in ACS patients remains a significant independent predictor of in-hospital mortality (adjusted OR 1.08; 95% confidence intervals [CI] 1.05-1.14, p<0.001) per mmol/L. The OR for in-hospital mortality was 1.04 (95% CI 0.99-1.1; p=0.140) per mmol/L for patients with diabetes but 1.21 (95% CI 112-1.30; p<0.001) per mmol/L for non-diabetic patients. In conclusion, elevated glucose level in ACS patients on admission is a significant independent predictor of in-hospital mortality and is even more important for patients who do not have known diabetes.

Glycemia and inflammatory markers in acute coronary syndrome: association with late post-hospital outcomes

BACKGROUND

Glycemia and inflammatory markers were associated with clinical outcomes in patients with acute coronary syndrome (ACS).

OBJECTIVES

To evaluate the role of glycemia and inflammatory markers as predictors of late cardiovascular outcomes after ACS.

METHODS

One hundred and ninety-nine ACS patients of a Coronary Care Unit were included, from March to November 2002. They were reassessed clinically after approximately 3 years. Clinical variables, glycemia, CRP and fibrinogen were evaluated as event and mortality predictors. Statistical analyses included Cox multivariate analysis and survival curves (Kaplan-Meier).

RESULTS

At admission, 16.7% had normal glycemia. After 3 years, this proportion increased to 55.2%; the 40.6% who belonged to the borderline category decreased to 27.1%; the 42.7% with elevated glycemia decreased to 17.7%. Glycemia was not associated with the development of major cardiovascular events (MACE) and mortality at follow-up ( approximately 3 years). Considering MACE, CRP (p<0.001), but not fibrinogen, was predictive in bivariate analysis. Regarding mortality, both fibrinogen (p=0.020) and CRP (p=0.008) were predictive in bivariate analysis.

CONCLUSION

Glycemia was not associated with late mortality after ACS, but inflammatory markers were, suggesting that these are more sensitive markers to predict events in long-term. Moreover, glucose intolerance prevalence is lower in the follow-up after the ACS episode.

Glutathione suppresses increase of serum creatine kinase in experimental hypoglycemia

Inhibitory effects of reduced glutathione (GSH) on serum enzymes including alanine aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK) were investigated in the hypoglycemic rabbits. Hypoglycemia lasting for 60 min was induced by intravenous injection of insulin (10U/kg) and then recovered by intravenous glucose injection. Serum levels of ALT, AST, LDH and CK increased significantly (p<0.05) at 6h after the induction of hypoglycemia. Plasma GSH, oxidized glutathione (GSSG) and total glutathione (TGSH) began to increase significantly (p<0.05) at 1h after the insulin injection, and GSSG/TGSH ratio rose significantly (p<0.05) at 6h after the induction of hypoglycemia. GSSG contents and GSSG/TGSH ratio in quadriceps significantly increased during hypoglycemia. Administration of GSH significantly decreased plasma GSSG levels, GSSG/TGSH ratio (p<0.05) and suppressed the rise of serum enzymes induced by hypoglycemia. These results suggest that GSH administration may play a preventive role for increases of serum enzymes by experimental hypoglycemia.

Prognostic implication of hyperglycemia in myocardial infarction and primary angioplasty

PURPOSE

The study assessed the relationship of admission blood glucose level to in-hospital mortality in patients presenting with an ST-segment elevation myocardial infarction and treated with primary angioplasty.

METHODS

A total of 980 patients presenting with an ST-segment elevation myocardial infarction and treated exclusively with primary angioplasty were evaluated. Patients were divided into quartiles based on their admission blood glucose level: group 1 (< or =6.6 mmol/L [< or =119 mg/dL]), group 2 (6.7-7.8 mmol/L [120-140 mg/dL]), group 3 (7.9-10.0 mmol/L [141-180 mg/dL], and group 4 (> or =10.1 mmol/L [> or =181 mg/dL]. The primary end point was in-hospital mortality.

RESULTS

The mean age of the patient cohort was 62 years, 260 (27%) of whom were female. The mean admission blood glucose level was 9.1+/-4.4 mmol/L (164+/-79 mg/dL). At admission, 16% of this group were known to have diabetes. The in-hospital mortality rate was 3.8% (n=37), 5.2% in the diabetic group (n=8) and 3.5% (n=29) in the nondiabetic group. In-hospital mortality rates were significantly increased in patients with an elevated admission blood glucose level (P<.001). The in-hospital deaths in each admission blood glucose level quartile were 0.4% (n=1) in group 1, 2% (n=6) in group 2, 2% (n=6) in group 3, and 10% (n=24) in group 4.

CONCLUSIONS

In this cohort of patients who were admitted with an ST-segment elevation myocardial infarction and treated exclusively with primary angioplasty, elevated admission blood glucose level is significantly associated with an increase in in-hospital mortality.

Hypoglycemia in the intensive care unit

PURPOSE OF REVIEW

To review recent articles and evaluate hypoglycemia as a major complication of intensive insulin therapy in anticipation of emerging data from current clinical studies.

RECENT FINDINGS

Following the 2001 landmark Leuven study demonstrating that intensive insulin therapy in the surgical intensive care unit reduces mortality, many studies have evaluated aspects of intensive insulin therapy with respect to improved clinical outcome and the impact of hypoglycemia. Specific risk factors for hypoglycemia in the intensive care unit with intensive insulin therapy are diabetes, octreotide therapy, nutrition support, continuous venovenous hemofiltration with bicarbonate replacement fluid, sepsis and need for inotropic support. In prospective studies with a comparator group, the incidence of hypoglycemia in intensive care unit patients treated with intensive insulin therapy is up to 25%, corresponding to a relative risk of 5.0. In studies without a comparator group, however, the incidence is less than 7%.

SUMMARY

Hypoglycemia is associated with adverse outcome in intensive care unit patients. It remains unclear whether intensive insulin therapy-induced hypoglycemia per se is responsible for this adverse outcome. The threat of hypoglycemia is a barrier to intensive insulin therapy in critical care, supporting the need for frequent glucose monitoring, readily available concentrated intravenous dextrose infusions, better training of nurses and technological advances in glucose-sensing and insulin-dosing algorithms.

Impact of the metabolic syndrome on the clinical outcomes of non-clinically diagnosed diabetic patients with acute coronary syndrome

The aim of this study is to explore the impact of metabolic syndrome (MS) on the outcome of patients with non-clinically diagnosed diabetes with acute coronary syndrome (ACS) based on a comprehensive nationwide registry during a 1-year follow-up. In the ACS Israeli Survey, 1,060 consecutive patients with non-clinically diagnosed diabetes were admitted due to ACS; 359 patients with MS features on admission were compared with 701 subjects without MS. A modified National Cholesterol Education Program Adult Treatment Panel III definition of MS was used in patients who presented with > or =3 of the 5 components: (1) hyperglycemia, defined as occasional blood glucose on admission >140 mg/dl; (2) preexisting hypertension; (3) body mass index >28 kg/m(2); (4) high-density lipoprotein cholesterol < or =40 mg/dl (men) or < or =50 mg/dl (women); and (5) triglycerides > or =150 mg/dl. Patients with MS were more frequently women (27% vs 12%, p = 0.001), were in Killip > or =II on admission (19% vs 14%, p = 0.03), and had higher 30-day (5.0% vs 1.7%, p = 0.002) and 1-year (8.9% vs 4.6%, p = 0.005) crude mortality rates. Patients with hyperglycemia (glucose >140 mg/dl) and MS had higher 30-day mortality rates compared with patients with hyperglycemia without MS (8.3% vs 2.5%, p <0.05). Multivariate analysis identified MS as a strong independent predictor of 30-day and 1-year mortality with hazard ratios of 2.54 (95% confidence interval 1.22 to 5.31) and 1.96 (95% confidence interval 1.18 to 3.24), respectively. In conclusion, MS defined early at admission is a strong independent predictor of mortality and morbidity in patients with non-clinically diagnosed diabetes with ACS.

Hyperglycemia in the pediatric intensive care unit

PURPOSE OF REVIEW

Studies on critically ill adults demonstrate the benefits of glycemic control. There is a paucity of data, however, in pediatric intensive care settings. This review summarizes sentinel papers in the adult literature, outlines mechanisms by which hyperglycemia mediates its effects in the critically ill, highlighting those described in pediatrics, and discusses studies that associate hyperglycemia with negative outcome in critically ill children.

RECENT FINDINGS

Retrospective studies and prospective cohort studies have linked hyperglycemia to worse outcome in critically ill children. Investigations in small, homogenous groups, such as trauma, sepsis, burn and neonatal patients, have shown negative associations between hyperglycemia and injury-specific outcomes and have elucidated previously proposed mechanisms of tissue injury in children. In addition, certain properties of hyperglycemia, such as duration, peak, and excursion, may be more relevant than absolute levels of glucose. Larger studies generalize findings to heterogeneous pediatric intensive care populations, across ages and diagnoses. Further, in studies accounting for insulin administration, no obvious increases in hypoglycemia-related morbidity have been noted.

SUMMARY

Glucose control in pediatric intensive care has been receiving increasing attention. Large, prospective studies are needed to address certain issues in pediatrics, such as differences in diseases, target values, complications of disease, risks and sequelae of hypoglycemia and logistical challenges.

Practical aspects of intensive insulinization in the intensive care unit

PURPOSE OF REVIEW

Strategies used for intensive insulin therapy of critically ill patients and differences of approach according to medical condition are reviewed.

RECENT FINDINGS

Acceptance of proposed glycemic targets for critically ill patients has been tempered by uncertainties about benefit of strict glycemic control for specific target subpopulations, differences between treatment centers, optimal timing and duration of intervention, and safety. Present-day intravenous insulin infusion protocols may perform well only for restricted populations. Assessment of protocol performance requires knowledge of algorithm behavior on or near the narrow target range and, using the patient as unit of observation, examination of glycemic variability. Systems of the future will permit adjustment of algorithm parameters to meet individual- or population-specific targets and match carbohydrate exposure.

SUMMARY

Attainment and preservation of glycemic control among critically ill patients are best attempted with intravenous insulin infusion. Advances in the design of decision support and insulin delivery systems, and progress in the technology of continuous blood glucose monitoring, are likely to reduce the risk of hypoglycemia, without compromise of target range control, such that the patient outcomes enjoyed by experienced centers in the future will prove generalizable to others through the extension of new technologies.

One year outcomes after glucose-insulin-potassium in ST elevation myocardial infarction. The Glucose-insulin-potassium study II

BACKGROUND

There are conflicting data concerning the effect of treatment with glucose-insulin-potassium (GIK) in ST segment elevation myocardial infarction (STEMI). Early studies showed beneficial effects of GIK, however, recent large sample size trials did not confirm this, or suggested only benefits in patients without heart failure. We aimed to evaluate long-term effects of GIK in patients with STEMI without signs of heart failure, all treated with reperfusion therapy.

METHODS

From August 2003 to December 2004, 889 STEMI patients without signs of heart failure were randomized to standard care (N=445) or additional GIK infusion (N=444). Glucose-potassium (20% glucose with 80 mmol potassium/l) was infused at 2 ml/kg body weight per hour for 12 h through a peripheral line. Short-acting insulin was started according to admission glucose and adjusted based on hourly measured glucose. Clinical end points were of number of death, reinfarction and revascularization at 1 year.

RESULTS

One year follow-up was available in 864 patients (97.2%), 432 in the GIK group and 432 in the control group. Mortality rate was 5.3% in GIK and 3.9% in control patients, p=0.33. Rates of reinfarction and revascularization 4.6% vs. 4.6% and 15.5% and 15.0%, in GIK vs. control patients.

CONCLUSION

In patients with STEMI without signs of heart failure treated with reperfusion therapy, GIK therapy offers no clinical benefit at 1 year.

Multivariate models of health-related utility and the fear of hypoglycaemia in people with diabetes

AIM

The aim was to statistically model the degree of fear of hypoglycaemia experienced by people with diabetes, and then model the resulting change in health-related utility associated with differing severity and frequency of hypoglycaemia.

METHODS

The study used pooled data from two previous postal surveys among subjects with confirmed diabetes conducted in Cardiff, UK (n = 1305 responses). The fear of hypoglycaemia was characterised using the Hypoglycaemia Fear Survey (HFS [eight question worry sub-scale only]), and health-related utility using the EQ5D(index). The data were then analysed using univariate and multivariate analysis.

RESULTS

Following detailed preliminary analysis, a two-stage approach was used since fear was important when estimating the EQ5D(index). Fear was then modelled as a function of the severity and frequency of hypoglycaemia while controlling for other factors such as diabetes-related complications. Each severe hypoglycaemic event resulted in a change of 5.881 units on the HFS. One or more symptomatic hypoglycaemic events over the same period results in a corresponding change of 1.773 units on the HFS. A 1 unit increase on the HFS results in a 0.008 unit decrease on the EQ5D(index).

CONCLUSION

While controlling for other factors, the fear of hypoglycaemia was an important determinant of health-related utility. The magnitude of fear of hypoglycaemia was associated with the severity and frequency of hypoglycaemia. Hypoglycaemia was associated with a considerable decrement in health-related utility as a function of increased fear. Measures should be taken to minimise the severity and frequency of hypoglycaemia.

Admission glycaemia and outcome after acute coronary syndrome

BACKGROUND

Acute phase hyperglycaemia has been associated with increased mortality in patients with acute coronary syndrome. We investigated whether the predictive value of admission hyperglycaemia for mortality differs between diabetics and non-diabetics with acute coronary syndrome.

METHODS

Patients with acute coronary syndrome (n=1957) were followed up prospectively for 45 months. Patients were stratified into quartile groups defined by admission plasma glucose and hyperglycaemia was defined as plasma glucose of >9.4 mmol/l, which was the cut-off value for the 4th quartile. The relationship between admission hyperglycaemia and short-term (< or =30 day) and late (>30 day) mortality was analysed.

RESULTS

Of 1957 patients, 22% had a history of diabetes. Among patients without diabetes, those with hyperglycaemia had both a higher 30-day mortality rate (20.2% vs. 3.5%, p<0.0001) and late mortality rate (19.1% vs. 11.7%, p=0.007). Hyperglycaemic patients with diabetes had a higher late mortality rate than diabetic patients with plasma glucose of < or =9.4 mmol/l (29.3% vs. 14.9%, p=0.001). Of patients with hyperglycaemia at admission, those without diabetes had a higher 30-day mortality rate compared with those with diabetes (p=0.002).

CONCLUSION

Admission hyperglycaemia is a strong risk factor for mortality in patients with acute coronary syndrome and may be even stronger than a previous history of diabetes. Hyperglycaemic patients without recognised diabetes have a higher short-term mortality risk than hyperglycaemic patients with known diabetes.

Newly Diagnosed Diabetes/Hyperglycemia in Hospitals: What Should We Do?

OBJECTIVE

To examine the clinical problem of newly diagnosed diabetes/hyperglycemia in hospitals, and to develop a management strategy.

METHODS

A review of the literature on outcomes and management of such patients.

RESULTS

There are very few published papers on this subject, the majority being in patients with cardiovascular disease. However, there is recognition that the problem is common. No randomized clinic trials have been carried out on therapeutic strategies in such patients. The limited data available suggest that patients with newly diagnosed diabetes and hyperglycemia tend to have a poor prognosis.

CONCLUSION

Newly diagnosed diabetes/hyperglycemia in hospital is a common problem and is associated with a poor prognosis. Therefore, it seems appropriate that such patients be managed the same way as patients with established diabetes. Following discharge, appropriate diagnostic testing is needed to establish the presence or absence of diabetes so that long-term treatment plans can be initiated.

Glycemic control and macrovascular disease in types 1 and 2 diabetes mellitus: Meta-analysis of randomized trials

BACKGROUND

Uncertainty persists concerning the effect of improved long-term glycemic control on macrovascular disease in diabetes mellitus (DM).

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials comparing interventions to improve glycemic control with conventional treatment in type 1 and type 2 diabetes. Outcomes included the incidence rate ratios for any macrovascular event, cardiac events, stroke, and peripheral arterial disease, and the number needed to treat intensively during 10 years to prevent one macrovascular event.

RESULTS

The analysis was based on 8 randomized comparisons including 1800 patients with type 1 DM (134 macrovascular events, 40 cardiac events, 88 peripheral vascular events, 6 cerebrovascular events, 11293 person-years of follow-up) and 6 comparisons including 4472 patients with type 2 DM (1587 macrovascular events, 1197 cardiac events, 87 peripheral vascular events, 303 cerebrovascular events, 43607 person-years). Combined incidence rate ratios for any macrovascular event were 0.38 (95% CI 0.26-0.56) in type 1 and 0.81 (0.73-0.91) in type 2 DM. In type 1 DM, effect was mainly based on reduction of cardiac and peripheral vascular events and, in type 2 DM, due to reductions in stroke and peripheral vascular events. Effects appear to be particularly important in younger patients with shorter duration of diabetes.

CONCLUSIONS

Our data suggest that attempts to improve glycemic control reduce the incidence of macrovascular events both in type 1 and type 2 DM. In absolute terms, benefits are comparable, although effects on specific manifestations of macrovascular disease differ.

Association between blood glucose and long-term mortality in patients with acute coronary syndromes in the OPUS-TIMI 16 trial

Hyperglycemia in the context of acute coronary syndrome (ACS) is a common observation, and existing data suggest that high glucose levels are associated with increased in-hospital mortality. We assessed the relation between random glucose and long-term mortality in 9,020 patients with ACS who were enrolled in the OPUS-TIMI 16 trial. A significant relation between glucose level and 10-month mortality was observed (2.7% in quartile 1 vs 7.0% in quartile 4, p <0.0001). After multivariable adjustment for co-morbidity, which included history of diabetes, this relation remained significant (quartile 4 vs 1, hazard ratio 1.70, 95% confidence interval 1.16 to 2.50, p = 0.006). These observations were similar in the TACTICS-TIMI 18 trial. In addition, we observed that B-type natriuretic peptide and troponin I levels increased across glucose quartiles in the OPUS-TIMI 16 trial (p values for trend = 0.002 and 0.0001, respectively) and the TACTICS-TIMI 18 trial (p values for trend = 0.006 and 0.0001, respectively). High blood glucose during ACS is an independent predictor of long-term mortality and is significantly correlated with prognostic biomarkers. Glucose levels during ACS may be an important addition to the risk stratification of patients with ACS and a potentially important target for therapy.

Prognostic significance of the change in glucose level in the first 24 h after acute myocardial infarction: results from the CARDINAL study

AIMS

In acute myocardial infarction (AMI), baseline hyperglycaemia predicts adverse outcomes, but the relation between subsequent change in glucose levels and outcomes is unclear. We evaluated the prognostic significance of baseline glucose and the change in glucose in the first 24 h following AMI.

METHODS AND RESULTS

We analysed 1469 AMI patients with baseline and 24 h glucose data from the CARDINAL trial database. Baseline glucose and the 24 h change in glucose (24 h glucose level subtracted from baseline glucose) were included in multivariable models for 30- and 180-day mortality. By 30 and 180 days, respectively, 45 and 74 patients had died. In the multivariable 30-day mortality model, neither baseline glucose nor the 24 h change in glucose predicted mortality in diabetic patients (n=250). However, in nondiabetic patients (n=1219), higher baseline glucose predicted higher mortality [hazard ratio (HR) 1.12, 95% confidence interval (CI) 1.04-1.20, per 0.6 mmol/L increase], and a greater 24 h change in glucose predicted lower mortality (HR 0.91, 95% CI 0.86-0.96, for every 0.6 mmol/L drop in glucose in the first 24 h) at 30 days. Baseline glucose and the 24 h change in glucose remained significant multivariable mortality predictors at 180 days in nondiabetic patients.

CONCLUSION

Both higher baseline glucose and the failure of glucose levels to decrease in the first 24 h after AMI predict higher mortality in nondiabetic patients.

The acute reperfusion management of STEMI in patients with impaired glucose tolerance and type 2 diabetes

Diabetes mellitus (DM) remains an important predictor for mortality in patients with ST-segment Elevation Myocardial Infarction (STEMI) although the use of reperfusion therapy has resulted in a considerable improvement of survival. Of importance, newly diagnosed diabetic patients and those with fasting glycaemia in the diabetes range have even worse outcomes compared to patients with known diabetes. Overall, 50% of all patients presenting with STEMI have abnormal glucose metabolism of which fewer than 50% are known diabetics. Obviously, the efficacy of reperfusion therapy in reopening the occluded artery is similar in STEMI patients with or without impaired fasting glycaemia, while the pre-existing decreased myocardial perfusion in STEMI patients with impaired fasting glycaemia persists after successful epicardial revascularisation. There is no doubt that improving microvascular perfusion within the ischaemic myocardium remains the ultimate goal of managing STEMI patients with impaired glucose metabolism. Identification of defective myocardial perfusion together with an aggressive antithrombotic regimen, reduction of the inflammatory response of the ischaemic myocardium and improvement of glycaemia control represent promising therapeutic approaches that deserve additional specific clinical investigations. This review examines all these important issues.