Effect of Insulin Therapy on Nonglycemic Variables During Acute Illness

Hyperglycemia at the Time of Acquiring Central Catheter-Associated Bloodstream Infections Is Associated With Mortality in Critically Ill Children

OBJECTIVES

Hyperglycemia is common and may be a risk factor for nosocomial infections, including central catheter-associated bloodstream infections in critically ill children. It is unknown whether hyperglycemia at the time of acquiring central catheter-associated bloodstream infections in pediatric critical illness is associated with worse outcomes. We hypothesized that hyperglycemia (blood glucose concentration > 126 mg/dL [> 7 mmol/L]) at the time of acquiring central catheter-associated bloodstream infections (from 4 d prior to the day of first positive blood culture, i.e., central catheter-associated bloodstream infections) in critically ill children is common and associated with ICU mortality.

DESIGN

Retrospective observational cohort study.

SETTING

Fifty-five-bed PICU and 26-bed cardiac ICU at an academic freestanding children's hospital.

PATIENTS

One hundred sixteen consecutively admitted critically ill children from January 1, 2008, to June 30, 2012, who were 0-21 years with central catheter-associated bloodstream infections were included. We excluded children with diabetes mellitus, metabolic disorders, and those with a "do not attempt resuscitation" order.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study cohort had an overall ICU mortality of 23%, with 48% of subjects developing hyperglycemia at the time of acquiring central catheter-associated bloodstream infections. Compared with survivors, nonsurvivors experienced more hyperglycemia both at the time of acquiring central catheter-associated bloodstream infections and subsequently. Median blood glucose at the time of acquiring central catheter-associated bloodstream infections was higher in nonsurvivors compared with survivors (139.5 mg/dL [7.7 mmol/L] vs 111 mg/dL [6.2 mmol/L]; p < 0.001) with 70% of nonsurvivors experiencing blood glucose greater than 126 mg/dL (> 7 mmol/L) during the 7 days following central catheter-associated bloodstream infections (in comparison to 45% of survivors; p = 0.03). After controlling for severity of illness and interventions, hyperglycemia at the time of acquiring central catheter-associated bloodstream infections was independently associated with ICU mortality (adjusted odds ratio, 1.9; 95% CI, 1.1-6.4; p = 0.03), in addition to other risk factors for ICU mortality (vasopressor use and severity of organ dysfunction).

CONCLUSIONS

Hyperglycemia at the time of acquiring central catheter-associated bloodstream infections is common and associated with ICU mortality in critically ill children. Strategies to monitor and control blood glucose to avoid hyperglycemia may improve outcomes in critically ill children experiencing central catheter-associated bloodstream infections.

Tight glycemic control after pediatric cardiac surgery in high-risk patient populations: a secondary analysis of the safe pediatric euglycemia after cardiac surgery trial

BACKGROUND

Our previous randomized, clinical trial showed that postoperative tight glycemic control (TGC) for children undergoing cardiac surgery did not reduce the rate of health care-associated infections compared with standard care (STD). Heterogeneity of treatment effect may exist within this population.

METHODS AND RESULTS

We performed a post hoc exploratory analysis of 980 children from birth to 36 months of age at the time of cardiac surgery who were randomized to postoperative TGC or STD in the intensive care unit. Significant interactions were observed between treatment group and both neonate (age ≤30 days; P=0.03) and intraoperative glucocorticoid exposure (P=0.03) on the risk of infection. The rate and incidence of infections in subjects ≤60 days old were significantly increased in the TGC compared with the STD group (rate: 13.5 versus 3.7 infections per 1000 cardiac intensive care unit days, P=0.01; incidence: 13% versus 4%, P=0.02), whereas infections among those >60 days of age were significantly reduced in the TGC compared with the STD group (rate: 5.0 versus 14.1 infections per 1000 cardiac intensive care unit days, P=0.02; incidence: 2% versus 5%, P=0.03); the interaction of treatment group by age subgroup was highly significant (P=0.001). Multivariable logistic regression controlling for the main effects revealed that previous cardiac surgery, chromosomal anomaly, and delayed sternal closure were independently associated with increased risk of infection.

CONCLUSIONS

This exploratory analysis demonstrated that TGC may lower the risk of infection in children >60 days of age at the time of cardiac surgery compared with children receiving STD. Meta-analyses of past and ongoing clinical trials are necessary to confirm these findings before clinical practice is altered.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00443599.

Design and rationale of safe pediatric euglycemia after cardiac surgery: a randomized controlled trial of tight glycemic control after pediatric cardiac surgery

OBJECTIVES

To describe the design of a clinical trial testing the hypothesis that children randomized to tight glycemic control with intensive insulin therapy after cardiac surgery will have improved clinical outcomes compared to children randomized to conventional blood glucose management.

DESIGN

Two-center, randomized controlled trial.

SETTING

Cardiac ICUs at two large academic pediatric centers.

PATIENTS

Children from birth to those aged 36 months recovering in the cardiac ICU after surgery with cardiopulmonary bypass.

INTERVENTIONS

Subjects in the tight glycemic control (intervention) group receive an intravenous insulin infusion titrated to achieve normoglycemia (target blood glucose range of 80-110 mg/dL; 4.4-6.1 mmol/L). The intervention begins at admission to the cardiac ICU from the operating room and terminates when the patient is ready for discharge from the ICU. Continuous glucose monitoring is performed during insulin infusion to minimize the risks of hypoglycemia. The standard care group has no target blood glucose range.

MEASUREMENTS AND MAIN RESULTS

The primary outcome is the development of any nosocomial infection (bloodstream, urinary tract, and surgical site infection or nosocomial pneumonia). Secondary outcomes include mortality, measures of cardiorespiratory function and recovery, laboratory indices of nutritional balance, immunologic, endocrinologic, and neurologic function, cardiac ICU and hospital length of stay, and neurodevelopmental outcome at 1 and 3 yrs of age. A total of 980 subjects will be enrolled (490 in each treatment arm) for sufficient power to show a 50% reduction in the prevalence of the primary outcome.

CONCLUSIONS

Pediatric cardiac surgery patients may recognize great benefit from tight glycemic control in the postoperative period, particularly with regard to reduction of nosocomial infections. The Safe Pediatric Euglycemia after Cardiac Surgery trial is designed to provide an unbiased answer to the question of whether this therapy is indeed beneficial and to define the associated risks of therapy.

Risk of postoperative hypoglycemia in cardiovascular surgical patients receiving computer-based versus paper-based insulin therapy

OBJECTIVE

To evaluate the safety and efficacy of replacing a paper-based protocol with a computer-guided glucose management system (CGMS) for the treatment of postoperative hyperglycemia in the cardiovascular intensive care unit (CVICU).

METHODS

With use of a before-and-after analysis, adult patients (≥18 years) discharged from the CVICU and treated with the paper protocol were compared with patients discharged from the CVICU and treated with the CGMS. Of the 1,648 patients analyzed, 991 were in the CGMS group. Clinical end points were evaluated by using the Wilcoxon test. Unadjusted and adjusted hazard ratios (HRs) for each hypoglycemic end point were calculated from Cox models with use of the proportional hazards regression procedure, and clinical end points were adjusted for potential confounders.

RESULTS

Patients treated with the paper protocol were 6 times as likely to experience clinical hypoglycemia (blood glucose ≤70 mg/dL) as patients treated with the CGMS (adjusted HR = 6.06; P<.0001) and more than 7 times as likely to experience severe hypoglycemia (blood glucose ≤40 mg/dL) (adjusted HR = 7.59; P=.01). Despite the increased risk of hypoglycemia, no significant difference in length of stay or mortality was observed between the groups.

CONCLUSION

CGMS treatment of postoperative hyperglycemia in CVICU patients can successfully attain goal glucose levels with a significant reduction in hypoglycemia in comparison with a paper protocol. This association persists after controlling for covariates.

A randomized controlled trial to evaluate the effect of glycemic control on renal transplantation outcomes

CONTEXT

Outcomes from intensive glycemic control postrenal transplant have not been studied.

OBJECTIVE

Our objective was to observe the optimal management of hyperglycemia in patients with diabetes or impaired glucose tolerance receiving renal transplantation.

DESIGN, SETTING, AND PATIENTS

We conducted a randomized controlled trial with patients undergoing renal transplantation randomized to either i.v. insulin therapy (intensive) or standard s.c. insulin therapy while the patients were admitted to the hospital.

INTERVENTIONS

The study consisted of a 3-day postrenal transplant group treated with intensive i.v. insulin [blood glucose (BG) = 70-110 mg/dl] or a control group treated with s.c. insulin (BG = 70-180 mg/dl).

MAIN OUTCOME MEASURE

The primary endpoint was delayed graft function (DGF). Secondary endpoints were glycemic control, graft survival, and acute rejection episodes.

RESULTS

A total of 104 patients were screened and randomized to either the intensive or control condition; however, the intention-to-treat analysis set consisted of only the 93 participants (n = 44 intensive, n = 49 control) that underwent a renal transplant. DGF was present in 18% (eight of 44) of the intensive group and 24% (12 of 49) of the control group (P = 0.46). The occurrence of severe hypoglycemia (BG < 40 mg/dl) and severe hyperglycemia (BG > 350 mg/dl) were the primary safety outcome measures. There were nine participants with hypoglycemia identified, seven of which (78%) were in the intensive treatment group (P = 0.08). There were 30 instances of hyperglycemia with five participants (11%) in the intensive group and 12 participants (24%) in the control group having at least one hyperglycemic event (P = 0.10). For the 11 rejection episodes, nine were in the intensive treatment group (P = 0.013).

CONCLUSIONS

The primary outcome measure of DGF was not statistically different for the two treatment groups. Regarding longer-term rejection and graft survival, the intensively treated participants were at higher risk for a rejection episode.

Inpatient diabetes: review of data from the cardiac care unit

OBJECTIVE

To review prospective and retrospective studies in an effort to assess the effect of glucose control on outcomes in critically ill populations.

METHODS

Results from recent prospective and retrospective studies are presented and analyzed in detail, with an emphasis on patients with myocardial infarction.

RESULTS

Retrospective observations show that, with the routine use of percutaneous coronary interventions, hyperglycemia continues to be a risk factor for mortality. In 2 prospective studies using glucose-insulin-potassium infusion, glucose levels did not reach target, and the results of both trials were negative with regard to the primary endpoint, mortality. However, progressive hyperglycemia was a risk factor for death in both prospective studies. It is an interesting paradox that diabetes actually may be protective for myocardial infarction. Although the reasons for this are not clear, one study showed that patients with diabetes were more likely to receive insulin for any given blood glucose level.

CONCLUSION

A study using variable-rate intravenous insulin infusion should be commissioned. In the meantime, clinicians should strive to achieve the best-possible glucose control in all patients with acute myocardial infarction and hyperglycemia. While we improve our understanding of the basic roles of glucose and insulin in modulating inflammation, we must aggressively treat hyperglycemia to the national goals for this population, which would substantially improve outcomes.

Effects of outcome on in-hospital transition from intravenous insulin infusion to subcutaneous therapy

It is widely accepted by medical practitioners that diabetes is a major independent risk factor for the development of cardiovascular disease. However, less attention has been directed toward elevated blood glucose as a predictor of poor outcomes in hospitalized patients in cardiac critical care. This has occurred despite documentation of hyperglycemia in a significant proportion of patients admitted for cardiac care and considerable data supporting the use of intravenous (IV) insulin to achieve glycemic control. The increased risk for mortality due to hyperglycemia provides a strong rationale for an intensive approach using insulin to control blood glucose levels in cardiac patients being treated in acute care and surgical settings. IV insulin infusion is the therapy of choice for patients in cardiac critical care units, with transition to a subcutaneous insulin therapy regimen when appropriate. The timing of this transition can be critical. Strong evidence from studies on patients who have undergone cardiac surgery suggests that glycemic control by insulin infusion should be maintained for > or =3 postoperative days. Nonetheless, transition from IV to subcutaneous therapy must occur at some point during the hospital stay. In conclusion, the implementation of measures to achieve glycemic control in acute cardiac care hospital settings can significantly reduce morbidity and mortality and can substantially decrease the costs associated with prolonged hospital stays. This report reviews recent clinical data on the benefits of IV insulin infusion in cardiac patients in critical care and provides recommendations on transitioning patients from IV insulin infusion to subcutaneous therapy.

Systematic strategies for improved outcomes for the hyperglycemic hospitalized patient with diabetes mellitus

Diabetes mellitus is reaching epidemic proportions in the United States. It is now the fourth most common comorbid condition complicating hospital discharges. There is a rapidly evolving body of literature assessing the short-term and long-term effects of strict glycemic control in the hospital setting. Results from several landmark studies have challenged the long-held notion that stress hyperglycemia is beneficial. This article will focus on these studies, postulated mechanisms of action, and finally, description of an insulin infusion protocol developed at a community hospital for patients undergoing cardiac surgery.

Inflammatory response during hyperglycemia and hyperinsulinemia in a porcine endotoxemic model: the contribution of essential organs

BACKGROUND

During euglycemia acute hyperinsulinemia diminishes the cytokine response to endotoxin [Lipopolysaccharide (LPS)] exposure. In this study we elucidated whether acute hyperglycemia and hyperinsulinemia modify the cytokine content in several organs during LPS challenge in a porcine model.

METHODS

Pigs (35-40 kg) were randomized to either normoglycemia (group 1, n = 8) or hyperglycemia and hyperinsulinemia (group 2, n = 8), anesthetized and mechanically ventilated. Both groups received a 180-min intravenous infusion of LPS (total 10 microg kg(-1)). Groups 1 and 2 were clamped at plasma glucose concentrations of 5 mM and 15 mM, respectively. Group 1 maintained a baseline insulin level while the hyperglycemic group exhibited increased insulin levels.

RESULTS

Circulating cytokines, cytokine mRNA and cytokine protein content were examined in the heart, liver, kidneys, lungs, spleen, adipose and muscle tissue. After LPS exposure, in both groups vast and equal plasma cytokines were elicited by approximately 70-5000-fold. A 10-fold higher level of IL-10, IL-6 and TNF-alpha protein was found in kidney tissue compared to the other organs together with a 3-10-fold increase of TNF-alpha in adipose tissue. However, cytokine mRNAs as well as organ function were without statistical difference between the groups.

CONCLUSION

Endotoxemia elicited a pronounced cytokine response in both plasma and at organ level. The kidneys and adipose tissue showed the highest cytokine protein content. Acute hyperglycemia apparently counteracts the well-established anti-inflammatory effects of insulin on the inflammatory response in a LPS challenged porcine model. Whether the observation can be extrapolated to more long-term stress-exposure remains to be clarified.

Hospital management of diabetes

The evidence continues to strengthen our understanding that improved glycemic control with the use of insulin therapy may significantly improve morbidity and mortality in hospitalized patients with hyperglycemia, with or without a previous diagnosis of diabetes. However, many questions remain concerning the impact and relative contributions of blood glucose and insulin per se. Nevertheless, the publication of numerous and consistent studies have made it clear that the topic of glycemic management in the hospital requires a larger priority among clinicians caring for these patients. The recently published guidelines by the American Association of Clinical Endocrinologists are the first formal recommendations on this topic,but national guidelines for blood glucose levels cannot take into account all of the different challenges facing different hospitals. This suggests that each institution will require individualization of protocols even though the ultimate metabolic goals are identical. Furthermore, it is not realistic to expect those unfamiliar with diabetes therapy to appreciate all of the nuances and vagaries of insulin treatment. Like any medical treatment, a significant amount of time will need to be invested by the providers involved with the.care of these patients before a mastery of the therapy can be achieved. Nevertheless, because the rewards to our patients can be significant, we need to strive to improve the systems where we work. Individual clinicians with vast experience in diabetes care cannot be successful for the inpatient with diabetes unless the hospital has systems in place to effectively and efficiently facilitate the management of the metabolic needs of this population. The main challenge now is the safe and effective implementation of these guidelines in both small and large hospitals given the limited level of re-sources available in today's medical environment. Therefore, our single most important recommendation is to ensure that all clinicians involved in the management of these patients are in agreement about general philosophies of diabetes management. We would recommend that there are "champions" for each discipline: endocrinology, cardiology, anesthesiology, surgery, nursing,and pharmacy, all of which have developed hospital-specific guidelines for glycemic management. These recommendations can be slowly adapted, one unit at a time, until the entire hospital has transitioned to a more "diabetes-friendly" environment. The ultimate goal of well-controlled glycemia with minimal hypoglycemia should be possible for most hospitals, and we hope this review will assist clinicians in achieving this objective. We await additional outcome research with carefully controlled studies to confirm the value of these recommendations at different levels of glycemic control. We believe that we can already state with confidence that the preliminary evidence shows that, like outpatient diabetes management,metabolic control matters during acute illness.

Depression-related hyperglycemia in type 1 diabetes: a mediational approach

OBJECTIVE

Depression is linked with hyperglycemia and with an increased risk for diabetes complications, but the mechanisms underlying these relationships have not been established. In this study, we applied mediational analysis methods to determine whether the hyperglycemic effect of depression could be mediated by poor diabetes self-care.

METHODS

Depression symptoms and diabetes self-care activity were assessed in a primary care sample of 188 patients with type 1 diabetes by using the Hopkins Symptom Checklist-90 (SCL-90) and the Summary of Diabetes Self-Care Activities (SDSCA). A composite score of self-care activity was formed from SDSCA ratings for diet amount, exercise, and glucose testing. Degree of hyperglycemia (level of glycosylated hemoglobin [HbA1c]), weight, insulin dose, and other clinical characteristics were obtained from electronic medical records. Ordinary least-squares regression was used to determine the effect of depression on HbA1c level controlling for weight and insulin dose. The SDSCA score was then added to the regression model to determine whether it attenuated the effect of depression symptoms on HbA1c level, thus providing suggestive evidence of mediation from these cross-sectional data.

RESULTS

Depression symptoms, poor diabetes self-care, and hyperglycemia were correlated with one another in univariate analyses (p <.05). Depression symptoms were associated with higher HbA1c after controlling for weight and insulin dose (parameter estimate for depression 0.53, t = 3.6, p <.001). Inclusion of SDSCA in the model minimally attenuated the effect of depression symptoms (adjusted parameter estimate for depression 0.50, t = 3.3, p = .001).

CONCLUSIONS

These findings do not support mediation of the depression-hyperglycemia relationship by diabetes self-care behavior. Other pathways, including psychophysiological mechanisms, should be investigated.

Inpatient management of hospitalized patients with type 2 diabetes

Over the past 4 years, the scientific literature addressing issues relevant to inpatient hyperglycemia and its management has grown dramatically but remains incomplete. The growing interest in inpatient diabetes management is particularly pertinent given the epidemic rise in the prevalence of type 2 diabetes and the associated increase in the proportion of inpatients carrying this diagnosis. The benefits of aggressive glucose control are well-established in certain admission categories. These benefits likely apply to many other admission diagnoses, but remain unproven at this time. Similarly, the best methods of glucose control remain uncertain in the various inpatient settings. Intensive insulin infusion therapy is becoming the standard care in the intensive care unit setting. Its use is also growing in less acute inpatient settings but requires further study. Inpatient subcutaneous insulin recommendations are general based on experience gained in the outpatient setting but offer a practical, physiologic approach.