Influence of hyperglycemia on stroke mortality

Circadian Factors in Stroke: A Clinician's Perspective

Stroke remains one of the leading causes of mortality and long-term and permanent disability worldwide despite technological innovations and developments in pharmacotherapy. In the last few decades, the growing data have evidenced the role of the circadian system in brain vulnerability to damage, the development and evolution of stroke, and short-term and long-term recovery. On the other hand, the stroke itself can affect the circadian system via direct injury of specific brain structures involved in circadian regulation (i.e., hypothalamus, retinohypothalamic tracts, etc.) and impairment of endogenous regulatory mechanisms, metabolic derangement, and a neurogenic inflammatory response in acute stroke. Moreover, the disruption of circadian rhythms can occur or exacerbate as a result of exogenous factors related to hospitalization itself, the conditions in the intensive care unit and the ward (light, noise, etc.), medication (sedatives and hypnotics), and loss of external factors entraining the circadian rhythms. In the acute phase of stroke, patients demonstrate abnormal circadian variations in circadian biomarkers (melatonin, cortisol), core body temperature, and rest-activity patterns. The approaches aimed at the restoration of disrupted circadian patterns include pharmacological (melatonin supplementation) and non-medication (bright light therapy, shifting feeding schedules, etc.) interventions; however, their effects on short- and long-term recovery after stroke are not well understood.

Incidence of Stress-Induced Hyperglycemia in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

The aim of this study was to systematically evaluate the incidence of stress-induced hyperglycemia (SIH) in acute ischemic stroke (AIS). Studies that reported SIH incidence in AIS and examined risk factors for SIH and non-SIH patients were systematically searched in PubMed, Embase, Cochrane Library, and Web of Science from the inception of each database to December 2021. Article screening and data extraction were performed by two independent reviewers according to the inclusion and exclusion criteria. The quality of the included studies was assessed using the Newcastle–Ottawa Scale (NOS), and meta-analysis was performed using Stata. A total of 13 studies involving 4552 patients (977 in the SIH group and 3575 in the non-SIH group) were included. Meta-analysis showed that the incidence of SIH was 24% (95% CI: 21–27%) in the total population, 33% (14–52%) in North America, 25% (20–29%) in Europe, and 21% (12–29%) in Asia. Subgroup analysis by year of publication revealed that the pooled incidence of SIH was 27% (22–32%) in studies published before 2010 and 19% (14–24%) in those published after 2010. SIH is relatively common in AIS and poses a serious public health problem. Therefore, more emphasis should be placed on the prevention and control of SIH in AIS.

Lipid Paradox in Statin-Naïve Acute Ischemic Stroke But Not Hemorrhagic Stroke

Background: Low lipid level is associated with better cardiovascular outcome. However, lipid paradox indicating low lipid level having worse outcomes could be seen under acute injury in some diseases. The present study was designed to clarify the prognostic significance of acute-phase lipid levels within 1 day after admission for stroke on mortality in first-ever statin-naïve acute ischemic stroke (IS) and hemorrhagic stroke (HS). Methods: This observational study was conducted using the data collected from Stroke Registry In Chang-Gung Healthcare System (SRICHS) between 2009 and 2012. Patients with recurrent stroke, onset of symptoms >1 day, and history of the use of lipid-lowering agents prior to index stroke were excluded. Stroke was classified into IS and hypertension-related HS. The primary outcomes were 30-day and 1-year mortality identified by linkage to national death registry for date and cause of death. Receiver operating characteristic (ROC) curve analysis and multivariate Cox proportional hazard models were used to examine the association of lipid profiles on admission with mortality. Results: Among the 18,268 admitted stroke patients, 3,746 IS and 465 HS patients were eligible for analysis. In IS, total cholesterol (TC) <163.5 mg/dL, triglyceride (TG) <94.5 mg/dL, low-density lipoprotein (LDL) <100 mg/dL, non-high-density lipoprotein cholesterol (non-HDL-C) <130.5 mg/dL, and TC/HDL ratio <4.06 had significantly higher risk for 30-day/1-year mortality with hazard ratio (HR) of 2.05/1.37, 1.65/1.31, 1.68/1.38, 1.80/1.41, and 1.58/1.38, respectively, compared with high TC, TG, LDL, non-HDL-C, and TC/HDL ratio (p < 0.01 in all cases). In HS, lipid profiles were not associated with mortality, except HDL for 30-day mortality (p = 0.025) and high uric acid (UA) concentrations for 30-day and 1-year mortality (p = 0.002 and 0.012, respectively). High fasting glucose and high National Institute of Health Stroke Scale (NIHSS) score at admission were associated with higher 30-day and 1-year mortality in both IS and HS and low blood pressure only in IS (p < 0.05). Synergic effects on mortality were found when low lipids were incorporated with high fasting glucose, low blood pressure, and high NIHSS score in IS (p < 0.05). Conclusions: Lipid paradox showing low acute-phase lipid levels with high mortality could be seen in statin-naïve acute IS but not in HS. The mortality in IS was increased when low lipids were incorporated with high fasting glucose, low blood pressure, and high NIHSS score.

Acute ischemic stroke and hyperglycemia

To increase the comprehension about the profound effects of hyperglycemia within the first 48 hours poststroke on the outcomes of acute ischemic stroke, the authors reviewed multiple studies and literature reviews. Research supports the detrimental effects of hyperglycemia on the morbidity and mortality of patients diagnosed with acute ischemic stroke. The studies that were examined revealed that although further research is necessary, controlling hyperglycemia is overall beneficial to support superior clinical outcomes. The purpose of this article was to discuss the importance of not only glucose control but also the vital role of nurses in controlling glucose levels efficiently and immediately during the first 48 hours poststroke.

Optimal glycemic control in neurocritical care patients: a systematic review and meta-analysis

INTRODUCTION

Hyper- and hypoglycemia are strongly associated with adverse outcomes in critical care. Neurologically injured patients are a unique subgroup, where optimal glycemic targets may differ, such that the findings of clinical trials involving heterogeneous critically ill patients may not apply.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing intensive insulin therapy with conventional glycemic control among patients with traumatic brain injury, ischemic or hemorrhagic stroke, anoxic encephalopathy, central nervous system infections or spinal cord injury.

RESULTS

Sixteen RCTs, involving 1248 neurocritical care patients, were included. Glycemic targets with intensive insulin ranged from 70-140 mg/dl (3.9-7.8 mmol/L), while conventional protocols aimed to keep glucose levels below 144-300 mg/dl (8.0-16.7 mmol/L). Tight glycemic control had no impact on mortality (RR 0.99; 95% CI 0.83-1.17; p = 0.88), but did result in fewer unfavorable neurological outcomes (RR 0.91; 95% CI 0.84-1.00; p = 0.04). However, improved outcomes were only observed when glucose levels in the conventional glycemic control group were permitted to be relatively high [threshold for insulin administration > 200 mg/dl (> 11.1 mmol/L)], but not with more intermediate glycemic targets [threshold for insulin administration 140-180 mg/dl (7.8-10.0 mmol/L)]. Hypoglycemia was far more common with intensive therapy (RR 3.10; 95% CI 1.54-6.23; p = 0.002), but there was a large degree of heterogeneity in the results of individual trials (Q = 47.9; p<0.0001; I2 = 75%). Mortality was non-significantly higher with intensive insulin in studies where the proportion of patients developing hypoglycemia was large (> 33%) (RR 1.17; 95% CI 0.79-1.75; p = 0.44).

CONCLUSIONS

Intensive insulin therapy significantly increases the risk of hypoglycemia and does not influence mortality among neurocritical care patients. Very loose glucose control is associated with worse neurological recovery and should be avoided. These results suggest that intermediate glycemic goals may be most appropriate.

Effects of hyperglycemia and effects of ketosis on cerebral perfusion, cerebral water distribution, and cerebral metabolism

Diabetic ketoacidosis (DKA) may cause brain injuries in children. The mechanisms responsible are difficult to elucidate because DKA involves multiple metabolic derangements. We aimed to determine the independent effects of hyperglycemia and ketosis on cerebral metabolism, blood flow, and water distribution. We used magnetic resonance spectroscopy to measure ratios of cerebral metabolites (ATP to inorganic phosphate [Pi], phosphocreatine [PCr] to Pi, N-acetyl aspartate [NAA] to creatine [Cr], and lactate to Cr) and diffusion-weighted imaging and perfusion-weighted imaging to assess cerebral water distribution (apparent diffusion coefficient [ADC] values) and cerebral blood flow (CBF) in three groups of juvenile rats (hyperglycemic, ketotic, and normal control). ATP-to-Pi ratio was reduced in both hyperglycemic and ketotic rats in comparison with controls. PCr-to-Pi ratio was reduced in the ketotic group, and there was a trend toward reduction in the hyperglycemic group. No significant differences were observed in NAA-to-Cr or lactate-to-Cr ratio. Cortical ADC was reduced in both groups (indicating brain cell swelling). Cortical CBF was also reduced in both groups. We conclude that both hyperglycemia and ketosis independently cause reductions in cerebral high-energy phosphates, CBF, and cortical ADC values. These effects may play a role in the pathophysiology of DKA-related brain injury.

A prospective study of predictors of prolonged hospital stay and disability after stroke

This study examined predictors of prolonged hospitalisation (>30 days) and significant disability (modified Rankin Scale >2) in 257 patients with acute ischaemic stroke. These patients were assessed prospectively regarding stroke severity, comorbidities and complications in hospital. Multivariate logistic regression was used to select variables that best predicted prolonged hospital stay and significant disability on discharge. Four factors significantly predicted prolonged hospital stay: older age (>65); diabetes mellitus; in-hospital infection; and significant disability on discharge. Significant disability on discharge was in turn associated with diabetes, infection, premorbid disability, stroke in progression and atrial fibrillation. Diabetes and in-hospital infection, together with other factors, can significantly predict prolonged hospital stay and disability in stroke patients. These two potentially modifiable factors are possible targets for interventions to reduce the burden of illness and healthcare costs of stroke.

Hyperglycaemia in acute ischaemic stroke is associated with an increased 5-year mortality

BACKGROUND

admission hyperglycaemia (HG) is associated with worse prognosis and higher mortality within 3 months after stroke. Reports on long-term mortality are inconsistent.

OBJECTIVE

to evaluate the influence of admission HG [blood glucose (BG) levels >8 mmol/L] on long-term mortality after ischaemic stroke (IS) and transient ischaemic attack (TIA).

METHODS

consecutive patients with IS or TIA, admitted from January 1997 until December 2002, were retrospectively screened. BG was measured within 3 days from onset of symptoms. Information on the date of death was obtained within 10 years after onset.

RESULTS

a total of 509 patients (78% IS; 22% TIA) were included. Admission HG was present in 28% and 18% of the IS and TIA patients, respectively (P = 0.05). Mean admission BG was 7.6 +/- 3.2 mmol/L in the IS and 6.7 +/- 2.3 mmol/L in TIA (P = 0.002). During a mean observation of 66 +/- 35 months, the overall 1- and 10-year mortality rate was 12% and 51% in IS compared to 4% and 38% in TIA patients (P = 0.004). Normoglycaemic IS patients had a longer median survival than those with HG (113 vs 84 months, P = 0.04). Admission HG did not affect the mortality rates in TIA patients.

CONCLUSION

admission HG is associated with greater mortality rates up to 5 years after stroke but does not influence the survival of TIA patients.

Homeostasis as basis of acute stroke treatment: stroke units are the key

INTRODUCTION

Several studies suggest that the control of blood pressure (BP), blood glucose level, body temperature, and oxygen saturation, when analyzed separately, is related with successful acute stroke outcome. However, in a biological system these parameters are interrelated and could influence the process. Recent studies highlight the importance of the appropriate maintenance of these variables that are involved in homeostasis in patients with stroke and the influence they have on outcome.

METHODS

A review was conducted of published studies which analyzed the influence of control of these physiological variables in acute stroke, whether in isolation or combinations, and we have contributed our own data derived from observational studies.

RESULTS

The maintenance of homeostasis forms the basis of acute stroke treatment, in what is termed nonpharmacological neuroprotection. Stroke units (SU) are the ideal environment for this therapeutic approach since their favorable influence on the correct management of BP, body temperature, oxygen saturation, and blood glucose in the progress of stroke patients have been proved.

CONCLUSIONS

The proper management of physiological variables (homeostasis) such as BP, body temperature, blood glucose, and oxygen saturation is the basis of acute stroke treatment, and SU are the key to this approach.

Acute Care in Stroke: The Importance of Early Intervention to Achieve Better Brain Protection

It is known that 'time is brain', and only early therapies in acute stroke have been effective, like thrombolysis within the first 3 h, and useful neuroprotective drugs are searched for that probably would be effective only with their very early administration. General care (respiratory and cardiac care, fluid and metabolic management, especially blood glucose and blood pressure control, early treatment of hyperthermia, and prevention and treatment of neurological and systemic complications) in acute stroke patients is essential and must already start in the prehospital setting and continue at the patient's arrival to hospital in the emergency room and in the stroke unit. A review of published studies analyzing the influence of general care on stroke outcome and the personal experience from observational studies was performed. Glucose levels >8 mmol/l have been found to be predictive of a poor prognosis after correcting for age, stroke severity, and stroke subtype. Although a clinical trial of glucose-insulin-potassium infusions is ongoing, increased plasma glucose levels should be treated. Moreover, insulin therapy in critically ill patients, including stroke patients, is safe and determines lower mortality and complication rates. Both high and low blood pressure levels have been related to a poor prognosis in acute stroke, although the target levels have not been defined yet in clinical trials. The body temperature has been shown to have a negative effect on stroke outcome, and its control and early treatment of hyperthermia are important. Hypoxemia also worsens the stroke prognosis, and oxygen therapy in case of <92% O(2) saturation is recommended. Besides, blood pressure stabilization avoiding falls of the diastolic pressure and the lowering of glycemia and temperature have been related to a better prognosis in stroke units patients, and homeostasis maintenance is associated with a better outcome. General care has become an emergent and first-line brain-protectant treatment that must be started at the prehospital level from the very beginning. This could help to save more brain tissue to get the best conditions for further specific stroke therapies such as the use of neuroprotective or thrombolytic drugs in the hospital.

Persistent poststroke hyperglycemia is independently associated with infarct expansion and worse clinical outcome

BACKGROUND AND PURPOSE

Hyperglycemia at the time of ischemic stroke is associated with increased mortality and morbidity. Animal studies suggest that infarct expansion may be responsible. The influence of persisting hyperglycemia after stroke has not previously been examined. We measured the blood glucose profile after acute ischemic stroke and correlated it with infarct volume changes using T2- and diffusion-weighted MRI.

METHODS

We recruited 25 subjects within 24 hours of ischemic stroke symptoms. Continuous glucose monitoring was performed with a glucose monitoring device (CGMS), and 4-hour capillary glucose levels (BGL) were measured for 72 hours after admission. MRI and clinical assessments were performed at acute (median, 15 hours), subacute (median, 5 days), and outcome (median, 85 days) time points.

RESULTS

Mean CGMS glucose and mean BGL glucose correlated with infarct volume change between acute and subacute diffusion-weighted MRI (r>or=0.60, P<0.01), acute and outcome MRI (r=0.56, P=0.01), outcome National Institutes of Health Stroke Scale (NIHSS; r>or=0.53, P<0.02), and outcome modified Rankin Scale (mRS; r>or=0.53, P=0.02). Acute and final infarct volume change and outcome NIHSS and mRS were significantly higher in patients with mean CGMS or mean BGL glucose >or=7 mmol/L. Multiple regression analysis indicated that both mean CGMS and BGL glucose levels >or=7 mmol/L were independently associated with increased final infarct volume change.

CONCLUSIONS

Persistent hyperglycemia on serial glucose monitoring is an independent determinant of infarct expansion and is associated with worse functional outcome. There is an urgent need to study normalization of blood glucose after stroke.

The influence of diabetes mellitus and hyperglycaemia on stroke incidence and outcome

Diabetes mellitus is a complex metabolic syndrome with significant effects on the systemic and cerebral vasculature. The incidence and severity of ischaemic stroke are increased by the presence of diabetes, and outcome from stroke is poorer. More than one third of patients admitted with acute stroke are hyperglycaemic at presentation. Reasons for the altered prognosis in diabetes associated stroke are multifactorial. A direct influence of hyperglycaemia at the time of ischaemia is likely to be important. The use of novel methods to delineate stroke topography and pathophysiology such as MR spectroscopy, diffusion and perfusion weighted MRI appear helpful in delineating the effects of hyperglycaemia on stroke pathophysiology. Randomised clinical trials to determine optimal management for patients with hyperglycaemia following stroke are ongoing. Such trials will determine if aggressive control of acute hyperglycaemia following stroke has similar benefits to that observed following acute myocardial infarction. Clinicians responsible for stroke patients should be aware of the importance of adequate glycaemic control in both primary and secondary prevention of stroke.