Effect of insulin therapy on coagulation and fibrinolysis in medical intensive care patients

Therapeutic effect of intensive glycemic control therapy in patients with traumatic brain injury: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Hyperglycemia is associated with dismal outcomes in patients with traumatic brain injury (TBI), which is frequently treated with insulin therapy. In this study, a systematic review and meta-analysis of the published randomized controlled trials (RCTs) was performed to assess the safety and efficacy of intensive glycemic control (IGC) versus conventional glycemic control (CGC) for patients following TBI.

METHODS

Databases, including PubMed, Embase, and the Cochran database, were retrieved up to January 2018. The outcomes evaluated in this study included mortality, neurological outcome, infection rate, hypoglycemia episode, and length of stay (LOS) in intensive care unit (ICU). The enrolled trials were analyzed using the Review Manager 5.3 software.

RESULTS

A total of 7 randomized controlled trials (RCTs) involving 1013 cases were enrolled in this study, and the results indicated no significant difference in 6-month mortality (risk ratio [RR], 0.92; 95% confidence interval [CI] 0.76-1.10; P = .34). Subsequently, IGC was associated with a better neurological outcome (RR, 1.22; 95% CI 1.05-1.43; P = .01), lower infection rate (RR, 0.65; 95% CI 0.51-0.82; P = .0003) and shorter LOS in ICU (mean difference [MD] = -1.37; 95%CI = -2.11, -0.63; P = .0003). In addition, IGC would also increase the risk of hypoglycemia episode (RR, 4.53; 95% CI 2.18-9.42; P < .001).

CONCLUSIONS

IGC plays a protective role in improving neurological outcome, decreasing infection rate and reducing the LOS in ICU. However, IGC therapy can also remarkably increase the risk of hypoglycemia, but it will not affect the mortality in TBI patients.

Venous thromboembolism has the same risk factors as atherosclerosis: A PRISMA-compliant systemic review and meta-analysis

BACKGROUND

Previous studies have shown that idiopathic pulmonary embolism is positively associated with other cardiovascular events, such as myocardial infarction and stroke, suggesting a potentially important association between atherosclerosis risk factors and venous thromboembolism (VTE). We performed a meta-analysis to evaluate the correlation between risk factors for atherosclerosis and VTE.

METHODS

In December 2014, we searched MEDLINE and EMBASE for studies evaluating the associations between VTE and risk factors for atherosclerosis and pooled outcome data using random-effects meta-analysis. In addition, we analyzed publication bias.

RESULTS

Thirty-three case-control and cohort studies with a total of 185,124 patients met the inclusion criteria. We found that participants with body mass index (BMI) ≥30 kg/m had a significantly higher prevalence of VTE than those with BMI <30 kg/m in both case-control studies (odds ratio [OR] = 2.45, 95% confidence interval [CI]: 1.78-3.35) and cohort studies (relative risk [RR] = 2.39, 95% CI: 1.79-3.17). VTE was more prevalent in patients with hypertension than without hypertension (OR = 1.40, 95% CI: 1.06-1.84; RR = 1.36, 95% CI: 1.11-1.67). The findings were similar for VTE prevalence between patients with and without diabetes (OR = 1.78, 95% CI: 1.17-2.69; RR = 1.41, 95% CI: 1.20-1.66). Current smoking was significantly associated with VTE prevalence in case-control studies (OR = 1.34, 95% CI: 1.01-1.77), but not in cohort studies (RR = 1.29, 95% CI: 0.96-1.72). In addition, we found that total cholesterol and triglyceride concentrations were significantly higher in patients with VTE than without VTE (weighted mean differences [WMD] = 8.94 mg/dL, 95% CI: 3.52-14.35 mg/dL, and WMD = 14.00 mg/dL, 95% CI: 8.85-19.16 mg/dL, respectively). High-density lipoprotein cholesterol concentrations were significantly lower in patients with VTE than without VTE (WMD = -2.03 mg/dL, 95% CI: -3.42 to -0.63 mg/dL). Higher quality studies were more homogeneous, but confirmed the same significant associations.

CONCLUSIONS

Based on our systematic review and meta-analysis, we observed a significant association between VTE and the risk factors for atherosclerosis. These results may make an important contribution to clinical practice regarding VTE treatment.

Association between early glycemic control and improvements in markers of coagulation and fibrinolysis in patients with septic shock-induced stress hyperglycemia

PURPOSE

The purpose of this study is to evaluate the coagulation and inflammatory profiles in septic shock patients with baseline hyperglycemia under glycemic control.

METHODS

Prospective, observational study conducted in an intensive care unit of a university hospital, including 41 septic shock nondiabetic patients with hyperglycemia (n = 21) or normoglycemia (n = 20) profiles at baseline. Hyperglycemic patients received a glucose control protocol (target glycemia, <150 mg/dL). Metabolic, inflammatory, and coagulation markers were measured at baseline and after 24 hours.

RESULTS

Median glycemic values between groups were different at baseline but not after 24 hours. Baseline coagulation profile was similar in both groups with elevated levels of coagulation markers, reduced factor VII, protein C, and antithrombin activities and fibrinolysis impairment. Normoglycemic patients had unchanged coagulation markers after 24 hours. After treatment, previously hyperglycemic patients exhibited increased plasminogen concentrations (P = .03) and reduced levels of plasminogen activator inhibitor 1 (P = .01) and tissue plasminogen activator (P = .03) as compared with baseline. They also had higher factor VII (P = .03), protein C (P = .04), and antithrombin (P = .04) activities than normoglycemic patients. Inflammatory markers were elevated in both groups and improved after 24 hours, independently of the glycemic profile.

CONCLUSIONS

Glycemic control during septic shock is associated with improvements in coagulation and fibrinolysis parameters compared with baseline and normoglycemic patients.

Blood glucose as a marker of venous thromboembolism in critically ill children

BACKGROUND

The ability to predict the development of venous thromboembolism is highly desirable.

OBJECTIVE

We aim to determine the association between hyperglycemia and venous thromboembolism in non-diabetic critically ill children.

PATIENTS/METHODS

We conducted a retrospective cohort study that included children in the pediatric intensive care unit on a vasopressor or mechanical ventilator and without history of diabetes mellitus or prior diagnosis of thrombosis. Based on maximum blood glucose > 150 mg dL(-1) while admitted to the unit, children were categorized as hyperglycemic or non-hyperglycemic. The primary outcome was development of venous thromboembolism while admitted to the unit. We determined the association between hyperglycemia and venous thromboembolism using logistic regression models adjusting for selected subject characteristics.

RESULTS

Of the 789 subjects analyzed, 34 subjects developed venous thromboembolism (incidence, 4.3%; 95% confidence interval, 3-6%). Venous thromboembolism was more likely to develop in hyperglycemic subjects compared with non-hyperglycemic subjects. A total of 31 subjects (6.2%; 95% confidence interval, 4.2-8.7%) developed venous thromboembolism after becoming hyperglycemic compared with three non-hyperglycemic subjects with venous thromboembolism (1%; 95% confidence interval, 0.2-3%). When adjusted for age, diagnosis, presence of central venous catheter, prophylactic antithrombotic use and severity of illness, the odds ratio of venous thromboembolism with hyperglycemia was 4.1 (95% confidence interval, 1.2-14.1). For every 10 mg dL(-1) increase in maximum blood glucose, the adjusted odds ratio of venous thromboembolism was 1.04 (95% confidence interval, 1.01-1.06).

CONCLUSION

Hyperglycemia is associated with venous thromboembolism in critically ill non-diabetic children. Maximum blood glucose is a potential predictor of venous thromboembolism in this population.

Emerging drugs for the treatment of sepsis

INTRODUCTION

Despite improvement in medical care, severe sepsis and septic shock remain an unmet medical need. Their incidence is steadily increasing and the worldwide mortality ranges between 30% and 50%. This generates the need for agents that modulate the immune function of the host.

AREAS COVERED

Available agents can be divided into three categories according to their mechanism of action: i) agents that block bacterial products and inflammatory mediators. Hemoperfusion with polymyxin B embedded fiber device that blocks bacterial lipopolysaccharides (LPS) has given promising clinical results. Blockade of TNF-α with afelimomab and CytoFab appears promising; ii) modulators of immune function. Hydrocortisone stress replacement, intravenous infusion of clarithromycin and immunonutrition with omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) have all yielded positive clinical results. Recombinant thrombomodulin for patients with disseminated intravascular coagulation appears a promising alternative; and iii) immunostimulation. Meta-analysis of conducted trials disclosed the decrease of mortality in septic shock after administration of immunoglobulin preparations enriched with IgM.

EXPERT OPINION

The underlying pathophysiologic mechanisms in septic patients are highly individualized. As such, specific tools should be developed in the near future to define these differences and tailor therapeutic strategies accordingly.

Fat content in liver and skeletal muscle changes in a reciprocal manner in patients with acromegaly during combination therapy with a somatostatin analog and a GH receptor antagonist: a randomized clinical trial

CONTEXT

Pegvisomant is a GH antagonist, which is used for the treatment of acromegalic patients. It effectively blocks the hepatic and peripheral effects of GH, but transient elevations in circulating liver enzymes of unknown pathogenesis may occur, which seems to be more prevalent when the treatment is combined with a somatostatin analog (SA). Accumulation of intrahepatic lipid is a known cause of elevated liver enzymes, and there is evidence to suggest that GH impacts lipid content in liver and skeletal muscle.

OBJECTIVE

Our objective was to measure lipid content in liver and skeletal muscle in acromegalic patients before and after cotreatment with pegvisomant and SA as compared with SA monotherapy.

DESIGN

Eighteen acromegalic patients well controlled on SA monotherapy were randomized in a parallel study over 24 wk to 1) unchanged SA monotherapy, or 2) cotreatment with pegvisomant (15-30 mg twice a week) and SA (half the usual dosage).

SETTING

This was an investigator-initiated study in a single tertiary referral center.

MAIN OUTCOME MEASURES

Intrahepatic lipid (IHL) and intramyocellular lipid (IMCL) was assessed by ¹H magnetic resonance spectroscopy.

RESULTS

IHL increased in the cotreatment group compared with SA only (P = 0.002). The increase was positively correlated to weekly pegvisomant dose (r² = 0.52; P = 0.01). By contrast, IMCL decreased in the cotreatment group compared with SA only (P = 0.01). These changes related neither to insulin sensitivity nor inflammatory markers.

CONCLUSION

Cotreatment with pegvisomant and a reduced SA dose increase IHL and decrease IMCL compared with SA monotherapy. The clinical implications remain unclear, but increased IHL may be causally linked to the transient elevations in liver enzymes observed during pegvisomant treatment.

Critical illness evokes elevated circulating bile acids related to altered hepatic transporter and nuclear receptor expression

Hyperbilirubinemia is common during critical illness and is associated with adverse outcome. Whether hyperbilirubinemia reflects intensive care unit (ICU) cholestasis is unclear. Therefore, the aim of this study was to analyze hyperbilirubinemia in conjunction with serum bile acids (BAs) and the key steps in BA synthesis, transport, and regulation by nuclear receptors (NRs). Serum BA and bilirubin levels were determined in 130 ICU and 20 control patients. In liver biopsies messenger RNA (mRNA) expression of BA synthesis enzymes, BA transporters, and NRs was assessed. In a subset (40 ICU / 10 controls) immunohistochemical staining of the transporters and receptors together with a histological evaluation of cholestasis was performed. BA levels were much more elevated than bilirubin in ICU patients. Conjugated cholic acid (CA) and chenodeoxycholic acid (CDCA) were elevated, with an increased CA/CDCA ratio. Unconjugated BA did not differ between controls and patients. Despite elevated serum BA levels, CYP7A1 protein, the rate-limiting enzyme in BA synthesis, was not lowered in ICU patients. Also, protein expression of the apical bile salt export pump (BSEP) was decreased, whereas multidrug resistance-associated protein (MRP) 3 was strongly increased at the basolateral side. This reversal of BA transport toward the sinusoidal blood compartment is in line with the increased serum conjugated BA levels. Immunostaining showed marked down-regulation of nuclear farnesoid X receptor, retinoid X receptor alpha, constitutive androstane receptor, and pregnane X receptor nuclear protein levels.

CONCLUSION

Failure to inhibit BA synthesis, up-regulate canalicular BA export, and localize pivotal NR in the hepatocytic nuclei may indicate dysfunctional feedback regulation by increased BA levels. Alternatively, critical illness may result in maintained BA synthesis (CYP7A1), reversal of normal BA transport (BSEP/MRP3), and inhibition of the BA sensor (FXR/RXRα) to increase serum BA levels.

Critical illness induces alternative activation of M2 macrophages in adipose tissue

Introduction

We recently reported macrophage accumulation in adipose tissue of critically ill patients. Classically activated macrophage accumulation in adipose tissue is a known feature of obesity, where it is linked with increasing insulin resistance. However, the characteristics of adipose tissue macrophage accumulation in critical illness remain unknown.

Methods

We studied macrophage markers with immunostaining and gene expression in visceral and subcutaneous adipose tissue from healthy control subjects (n = 20) and non-surviving prolonged critically ill patients (n = 61). For comparison, also subcutaneous in vivo adipose tissue biopsies were studied from 15 prolonged critically ill patients.

Results

Subcutaneous and visceral adipose tissue biopsies from non-surviving prolonged critically ill patients displayed a large increase in macrophage staining. This staining corresponded with elevated gene expression of "alternatively activated" M2 macrophage markers arginase-1, IL-10 and CD163 and low levels of the "classically activated" M1 macrophage markers tumor necrosis factor (TNF)-α and inducible nitric-oxide synthase (iNOS). Immunostaining for CD163 confirmed positive M2 macrophage staining in both visceral and subcutaneous adipose tissue biopsies from critically ill patients. Surprisingly, circulating levels and tissue gene expression of the alternative M2 activators IL-4 and IL-13 were low and not different from controls. In contrast, adipose tissue protein levels of peroxisome proliferator-activated receptor-γ (PPARγ), a nuclear receptor required for M2 differentiation and acting downstream of IL-4, was markedly elevated in illness. In subcutaneous abdominal adipose tissue biopsies from surviving critically ill patients, we could confirm positive macrophage staining with CD68 and CD163. We also could confirm elevated arginase-1 gene expression and elevated PPARγ protein levels.

Conclusions

Unlike obesity, critical illness evokes adipose tissue accumulation of alternatively activated M2 macrophages, which have local anti-inflammatory and insulin sensitizing features. This M2 macrophage accumulation may contribute to the previously observed protective metabolic activity of adipose tissue during critical illness.

Immunomodulation in sepsis: state of the art and future perspective

Despite advances in supportive care of critically ill patients, sepsis remains an important cause of death worldwide. More than 750,000 individuals develop severe sepsis in North America annually, with a mortality rate varying between 35 and 50%. Over recent years, numerous efforts have been committed to understanding the pathophysiology of septic syndrome, as well as attempts to intervene in the inflammatory cascade with the aim of altering the outcome of the syndrome and to improve survival. Not all of these attempts have been successful. Issued guidelines by the International Sepsis Forum have incorporated only the use of corticosteroids, tight glycemic control and the use of recombinant activated protein C as recommendations for the management of the septic patient along with the initial resuscitation and infection-site control measures. These strategies along, with novel attempts of immunomodulation, are thoroughly reviewed in this article.

Organ failure and tight glycemic control in the SPRINT study

Introduction

Intensive care unit mortality is strongly associated with organ failure rate and severity. The sequential organ failure assessment (SOFA) score is used to evaluate the impact of a successful tight glycemic control (TGC) intervention (SPRINT) on organ failure, morbidity, and thus mortality.

Methods

A retrospective analysis of 371 patients (3,356 days) on SPRINT (August 2005 - April 2007) and 413 retrospective patients (3,211 days) from two years prior, matched by Acute Physiology and Chronic Health Evaluation (APACHE) III. SOFA is calculated daily for each patient. The effect of the SPRINT TGC intervention is assessed by comparing the percentage of patients with SOFA ≤5 each day and its trends over time and cohort/group. Organ-failure free days (all SOFA components ≤2) and number of organ failures (SOFA components >2) are also compared. Cumulative time in 4.0 to 7.0 mmol/L band (cTIB) was evaluated daily to link tightness and consistency of TGC (cTIB ≥0.5) to SOFA ≤5 using conditional and joint probabilities.

Results

Admission and maximum SOFA scores were similar (P = 0.20; P = 0.76), with similar time to maximum (median: one day; IQR: [1,3] days; P = 0.99). Median length of stay was similar (4.1 days SPRINT and 3.8 days Pre-SPRINT; P = 0.94). The percentage of patients with SOFA ≤5 is different over the first 14 days (P = 0.016), rising to approximately 75% for Pre-SPRINT and approximately 85% for SPRINT, with clear separation after two days. Organ-failure-free days were different (SPRINT = 41.6%; Pre-SPRINT = 36.5%; P < 0.0001) as were the percent of total possible organ failures (SPRINT = 16.0%; Pre-SPRINT = 19.0%; P < 0.0001). By Day 3 over 90% of SPRINT patients had cTIB ≥0.5 (37% Pre-SPRINT) reaching 100% by Day 7 (50% Pre-SPRINT). Conditional and joint probabilities indicate tighter, more consistent TGC under SPRINT (cTIB ≥0.5) increased the likelihood SOFA ≤5.

Conclusions

SPRINT TGC resolved organ failure faster, and for more patients, from similar admission and maximum SOFA scores, than conventional control. These reductions mirror the reduced mortality with SPRINT. The cTIB ≥0.5 metric provides a first benchmark linking TGC quality to organ failure. These results support other physiological and clinical results indicating the role tight, consistent TGC can play in reducing organ failure, morbidity and mortality, and should be validated on data from randomised trials.

Hyperglycemia: a prothrombotic factor?

Diabetes mellitus is characterized by a high risk of atherothrombotic events. What is more, venous thrombosis has also been found to occur more frequently in this patient group. This prothrombotic condition in diabetes is underpinned by laboratory findings of elevated coagulation factors and impaired fibrinolysis. Hyperglycemia plays an important role in the development of these hemostatic abnormalities, as is illustrated by the association with glycemic control and the improvement upon treatment of hyperglycemia. Interestingly, stress induced hyperglycemia, which is often transient, has also been associated with poor outcome in thrombotic disease. Similar laboratory findings suggest a common effect of acute vs. chronic hyperglycemia on the coagulation system. Many mechanisms have been proposed to explain this prothrombotic shift in hyperglycemia, such as a direct effect on gene transcription of coagulation factors caused by hyperglycemia-induced oxidative stress, loss of the endothelial glycocalyx layer, which harbours coagulation factors, and direct glycation of coagulation factors, altering their activity. In addition, both chronic and acute hyperglycemia are often accompanied by hyperinsulinemia, which has been shown to have prothrombotic effects as well. In conclusion, the laboratory evidence of the effects of both chronic and acute hyperglycemia suggests a prothrombotic shift. Additionally, hyperglycemia is associated with poor clinical outcome of thrombotic events. Whether intensive treatment of hyperglycemia can prevent hypercoagulability and improve clinical outcome remains to be investigated.

Intensive insulin therapy in severe traumatic brain injury: a randomized trial

BACKGROUND

Intensive insulin therapy (IIT) has been shown to reduce morbidity and mortality in critically ill patients. Little investigation has been done to find out whether it improves the prognosis of patients with severe traumatic brain injury (STBI).

METHODS

We conducted a prospective controlled study where adult patients with blunt STBI, with Glasgow Coma Scale <or=8, admitted to the intensive care unit (ICU) were randomly assigned to receive either IIT (maintenance of blood glucose between 80 mg/dL and 110 mg/dL with continuous insulin infusion) or conventional glycemic therapy (CGT) (maintenance of blood glucose below 180 mg/dL with subcutaneous insulin and insulin infusion only if blood glucose levels exceeded 220 mg/dL). The main outcome was Glasgow outcome scale 6 months after trauma. Secondary measures were hypoglycemia, incidence of infections, and days in ICU.

RESULTS

Of the 88 patients randomized, 42 were assigned to IIT and 46 to CGT. There was no difference (p = 0.63) in neurologic outcomes between the treatment groups: Glasgow outcome scale >3 was observed in 16 patients (41%) in the IIT and in 13 patients (32.5%) in the CGT group. More patients in the IIT group had hypoglycemia: 32 (82.1%), compared with 7 (17.5%) in the CGT group (p < 0.001). There were no differences in the number of days spent in the ICU (18.2 +/- 27.6 vs. 12.9 +/- 12.7) or in the sepsis rates (84.6% vs. 80%) between the groups.

CONCLUSION

In our study, IIT did not improve the neurologic outcome of patients with STBI but did increase the risk of hypoglycemia compared with CGT.

Alterations in adipose tissue during critical illness: An adaptive and protective response?

RATIONALE

Critical illness is characterized by lean tissue wasting, whereas adipose tissue is preserved. Overweight and obese critically ill patients may have a lower risk of death than lean patients, suggestive of a protective role for adipose tissue during illness.

OBJECTIVES

To investigate whether adipose tissue could protectively respond to critical illness by storing potentially toxic metabolites, such as excess circulating glucose and triglycerides.

METHODS

We studied adipose tissue morphology and metabolic activity markers in postmortem biopsies of 61 critically ill patients and 20 matched control subjects. Adipose morphology was also studied in in vivo biopsies of 27 patients and in a rabbit model of critical illness (n = 22).

MEASUREMENTS AND MAIN RESULTS

Adipose tissue from critically ill patients revealed a higher number and a smaller size of adipocytes and increased preadipocyte marker levels as compared with control subjects. Virtually all adipose biopsies from critically ill patients displayed positive macrophage staining. The animal model demonstrated similar changes. Glucose transporter levels and glucose content were increased. Glucokinase expression was up-regulated, whereas glycogen and glucose-6-phosphate levels were low. Acetyl CoA carboxylase protein and fatty acid synthase activity were increased. Hormone-sensitive lipase activity was not altered, whereas lipoprotein lipase activity was increased. A substantially increased AMP-activated protein kinase activity may play a crucial role.

CONCLUSIONS

Postmortem adipose tissue biopsies from critically ill patients displayed a larger number of small adipocytes in response to critical illness, revealing an increased ability to take up circulating glucose and triglycerides. Similar morphologic changes were present in vivo. Such changes may render adipose tissue biologically active as a functional storage depot for potentially toxic metabolites, thereby contributing to survival.

Molecular mechanisms behind clinical benefits of intensive insulin therapy during critical illness: glucose versus insulin

High blood glucose levels have been associated with morbidity and poor outcome in critically ill patients, irrespective of underlying pathology. In a large, randomised, controlled study the use of insulin therapy to maintain normoglycaemia for at least a few days improved survival and reduced morbidity of patients who are in a surgical intensive care unit (ICU). Since the publication of this landmark study, several other investigators have provided support for, whereas others have questioned, the beneficial effects of intensive insulin therapy. In this review, we discuss the investigated potential molecular mechanisms behind the clinical benefits of intensive insulin therapy. We first describe the molecular origin of hyperglycaemia and the impact of the therapy on insulin sensitivity. Next, the molecular basis of glucose toxicity in critical illness and the impact of intensive insulin therapy hereon are described, as well as other non-glucose-toxicity-related metabolic effects of intensive insulin therapy.

Adiponectin, retinol-binding protein 4, and leptin in protracted critical illness of pulmonary origin

Introduction

Critically ill patients requiring intensive care uniformly develop insulin resistance. This is most pronounced in patients with sepsis. Recently, several hormones secreted by adipose tissue have been identified to be involved in overall insulin sensitivity in metabolic syndrome-related conditions. However, little is known about these adipokines in critical illness.

Methods

We studied circulating levels of the adipokines adiponectin, retinol-binding protein 4 (RBP4), and leptin during critical illness, and the impact of intensive insulin therapy, a therapy shown to affect insulin sensitivity, in serum samples from prolonged critically ill patients with a respiratory critical illness (n = 318). For comparison, we studied healthy subjects (n = 22) and acutely stressed patients (n = 22).

Results

During acute critical illness, circulating levels of adiponectin, RBP4, and leptin were low. Patients with sepsis had lower levels of leptin and RBP4 than did nonseptic patients. When critical illness was sustained, adipokine levels returned to normal reference values. Insulin therapy enhanced adiponectin, blunted the rise of RBP4, and did not alter leptin levels.

Conclusions

Acute critical illness is associated with immediate, but transiently low serum adipokine levels. Adiponectin and RBP4 are associated with altered insulin resistance in critical illness.