Intensive insulin therapy in the intensive care unit: update on clinical impact and mechanisms of action

Electronic Glycemic Management System and Endocrinology Service Improve Value in Cardiac Surgery

BACKGROUND

Postoperative glycemic control improves cardiac surgery outcomes but insulin protocols are limited by complexity and inflexibility. We sought to evaluate the effect of implementing an electronic glycemic management system (eGMS) in conjunction with a cardiac surgery endocrinology consult service on glycemic control and outcomes after cardiac surgery.

METHODS

All patients with a calculated preoperative risk of mortality who underwent cardiac surgery before and after implementation of an eGMS and an endocrinology consult service were identified. Glycemic control and surgical outcomes were compared using univariate analysis, and multivariate regression was used to model the risk-adjusted effects of the interventions on glycemic control, surgical outcomes, and resource utilization. The health care-related value added by the interventions was calculated by dividing risk-adjusted outcomes by total hospital costs.

RESULTS

A total of 2612 patients were identified, with 1263 patients in the preimplementation cohort and 1349 in the postimplementation cohort. Multivariate regression demonstrated fewer postoperative hyperglycemic events (odds ratio [OR] 0.8, 95% CI, 0.65-0.99) after protocol implementation without an increase in hypoglycemic events (OR 0.96, 95% CI, 0.71-1.3). Average day-weighted mean glucose decreased from 144 to 138 mg/dL (P < .001). The improved glycemic control correlated with a risk-adjusted decrease in composite morbidity or mortality (OR 0.61, 95% CI, 0.47-0.79). Although hospital costs increased after implementation, the protocol increased health care-related value by 38%.

CONCLUSION

Implementation of a protocol consisting of an eGMS paired with a cardiac surgery-specific endocrinology consult service was associated with improved glycemic control and reduced morbidity. Despite higher costs health care-related value increased as a result of eGMS implementation.

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.

Fasting hyperglycemia upon hospital admission is associated with higher pneumonia complication rates among the elderly

BACKGROUND

Hyperglycemia is an independent predictor of adverse outcomes during hospitalization. In patients who have pneumonia, significant hyperglycemia is associated with poor outcomes. This study evaluates the interaction of the degree of hyperglycemia and complication rates stratified by age in non-critically ill patients admitted to the hospital for care of community-acquired pneumonia.

METHODS

Retrospective review of patient records coded for pneumonia. Analysis included 501 non-critically ill patients admitted to a tertiary care hospital in New York City. Data were stratified by diabetes status, age (less than 65 and 65 and over), and fasting blood glucose (FBG) within the first 24 hours of hospitalization. Among patients with no history of diabetes, FBG was stratified as "normal" [FBG /=126 mg/dl (7 mmol/l)]. The diabetic group included known diabetics regardless of FBG. The Pneumonia Severity Index (PSI) was calculated for all patients. Complications rates, hospital length of stay and mortality were compared among the groups.

RESULTS

In patients age 65 and older, complication rates were 16.7% in normoglycemics, 27.5% in the "mild-hyperglycemia" group, 28.6% in the "severe hyperglycemia" group, and 25.5% in those with known diabetes. The mild and severe-hyperglycemics had similar complication rates (p = 0.94). Compared to the normal group, mild and severe groups had higher rates of complications, p = 0.05 and p = 0.03, respectively. PSI tended to be higher in those over the age of 65. PSI was not significantly different when the normal, mild, severe, and known diabetes groups were compared. PSI did not predict complications for new hyperglycemia (normals' mean score 87, mild 84.7, severe 93.9, diabetics 100). Hospital mortality did not differ among groups. Length of stay was longer (p = 0.05) among mild-hyperglycemics (days = 8.4 s.e. 14.3) vs. normals (days = 6.2 s.e.6.5).

CONCLUSION

This study shows that FBS between 101-125 mg/dl (5.7-6.9 mmol/l) on hospital admission increases pneumonia complication rates among the elderly with no previous diagnosis of diabetes.

Impact of hyperglycemia on morbidity and mortality, length of hospitalization and rates of re-hospitalization in a general hospital setting in Brazil

BACKGROUND

Hyperglycemia in hospitalized patients is known to be related to a higher incidence of clinical and surgical complications and poorer outcomes. Adequate glycemic control and earlier diagnosis of type 2 diabetes during hospitalization are cost-effective measures.

METHODS

This prospective cohort study was designed to determine the impact of hyperglycemia on morbidity and mortality in a general hospital setting during a 3-month period by reviewing patients' records. The primary purposes of this trial were to verify that hyperglycemia was diagnosed properly and sufficiently early and that it was managed during the hospital stay; we also aimed to evaluate the relationship between in-hospital hyperglycemia control and outcomes such as complications during the hospital stay, extent of hospitalization, frequency of re-hospitalization, death rates and number of days in the ICU (Intensive Care Unit) after admission. Statistical analyses utilized the Kruskall-Wallis complemented by the "a posteriori" d.m.s. test, Spearman correlation and Chi-squared test, with a level of significance of 5% (p < 0.05).

RESULTS

We reviewed 779 patient records that fulfilled inclusion criteria. The patients were divided into 5 groups: group (1) diabetic with normal glycemic levels according to American Diabetes Association criteria for in-hospital patients (n = 123); group (2) diabetics with hyperglycemia (n = 76); group (3) non-diabetics with hyperglycemia (n = 225); group (4)diabetics and non-diabetics with persistent hyperglycemia during 3 consecutive days (n = 57) and group (5) those with normal glucose control (n = 298). Compared to patients in groups 1 and 5, patients in groups 2, 3 and 4 had significantly higher mortality rates (17.7% vs. 2.8%) and Intensive Care Unit admissions with complications (23.3% vs. 4.5%). Patients in group 4 had the longest hospitalizations (mean 15.5 days), and group 5 had the lowest re-hospitalization rate (mean of 1.28 hospitalizations). Only 184 (51.4%) hyperglycemic patients had received treatment. An insulin "sliding-scale" alone was the most frequent treatment used, and there was a wide variation in glucose target medical prescriptions. Intra Venous insulin infusion was used in 3.8% of patients in the ICU. Glycohemoglobin(A1C) was measured in 11 patients(2.2%).

CONCLUSIONS

Hospital hyperglycemia was correlated with, among other parameters, morbidity/mortality, length of hospitalization and number of re-hospitalizations. Most patients did not have their glycemic levels measured at the hospital; despite the high number of hyperglycemic patients not diagnosed as diabetics, A1C was not frequently measured. Even when patients are assessed for hyperglycemia, they were not treated properly.

Incretin-based therapies: review of the outpatient literature with implications for use in the hospital and after discharge

A large percentage of critically ill adult inpatients have type 2 diabetes, which may be undiagnosed or uncontrolled during hospitalization. Hyperglycemia complicates the therapeutic management of inpatients and leads to adverse outcomes, and intensive glycemic control with insulin reduces morbidity and mortality. Insulin therapy, however, is labor-intensive and time-consuming. More important, long-standing protocols such as the sliding scale do not provide adequate glucose control. Although more research is needed to determine the best methods for treating hyperglycemia in-hospital, the importance of achieving better glycemic control while reducing the risk of hypoglycemia has been demonstrated. Post-discharge diabetes care is equally important, as it is essential in improving long-term outcomes after a hospital stay. Hospital care providers can play an important role in effective antihyperglycemic regimens in patients with diabetes prior to discharge. Post-discharge management is a formidable challenge because of the availability of an array of oral antidiabetes agents, including metformin, sulfonylureas, and thiazolidinediones, each with distinct therapeutic and adverse event profiles. Incretin-based therapies offer a potentially useful option for post-discharge therapy, and possibly for inpatient diabetes treatment. Incretins are effective, safe, and well-tolerated; they are easier for patients to use compared with insulin injections (eg, continual glucose monitoring is not required); and they may provide long-term improvement of cardiovascular parameters and beta-cell function. This review examines the challenges to achieving glycemic control in the hospital setting and summarizes clinical data on the efficacy and safety of incretin-based therapies in their use in the hospital and after discharge.

Surviving sepsis campaign: a critical reappraisal

In 2002, the declaration of Barcelona launched a worldwide campaign that proposed to decrease in sepsis-related mortality by the introduction of evidence-based medicine into the management of sepsis. This paved the way for the publication of a wide selection of recommendations entitled the Surviving Sepsis Campaign (SSC) Guidelines. Whereas most of the medical community received the guidelines with enthusiasm, dissonant voices were made public just after its publication, and in recent years, the SSC guidelines were a source of intense debate, resulting in a recent revision of the guidelines. In the midst of a large controversy, it is evident that a critical reappraisal of the SSC guidelines is timely. In our opinion, whereas many relevant aspects of the SSC guidelines have been discussed, there are three major limitations that deserve a closer look, and they are sepsis as a public health issue, the weight of the evidence behind the recommendations, and the absence of recommendations related to the prevention of sepsis. In conclusion, although we recognize that the SSC is a valuable initiative, many of its present aspects must be revised to provide a clear message for clinicians taking care of sepsis patients at bedside. New guidelines should be based on solid evidence, have no interference from the pharmaceutical or medical equipment industry, and should have a stronger preventive and public health approach.

Glycemic penalty index for adequately assessing and comparing different blood glucose control algorithms

Introduction

Blood glucose (BG) control performed by intensive care unit (ICU) nurses is becoming standard practice for critically ill patients. New (semi-automated) 'BG control' algorithms (or 'insulin titration' algorithms) are under development, but these require stringent validation before they can replace the currently used algorithms. Existing methods for objectively comparing different insulin titration algorithms show weaknesses. In the current study, a new approach for appropriately assessing the adequacy of different algorithms is proposed.

Methods

Two ICU patient populations (with different baseline characteristics) were studied, both treated with a similar 'nurse-driven' insulin titration algorithm targeting BG levels of 80 to 110 mg/dl. A new method for objectively evaluating BG deviations from normoglycemia was founded on a smooth penalty function. Next, the performance of this new evaluation tool was compared with the current standard assessment methods, on an individual as well as a population basis. Finally, the impact of four selected parameters (the average BG sampling frequency, the duration of algorithm application, the severity of disease, and the type of illness) on the performance of an insulin titration algorithm was determined by multiple regression analysis.

Results

The glycemic penalty index (GPI) was proposed as a tool for assessing the overall glycemic control behavior in ICU patients. The GPI of a patient is the average of all penalties that are individually assigned to each measured BG value based on the optimized smooth penalty function. The computation of this index returns a number between 0 (no penalty) and 100 (the highest penalty). For some patients, the assessment of the BG control behavior using the traditional standard evaluation methods was different from the evaluation with GPI. Two parameters were found to have a significant impact on GPI: the BG sampling frequency and the duration of algorithm application. A higher BG sampling frequency and a longer algorithm application duration resulted in an apparently better performance, as indicated by a lower GPI.

Conclusion

The GPI is an alternative method for evaluating the performance of BG control algorithms. The blood glucose sampling frequency and the duration of algorithm application should be similar when comparing algorithms.

Inpatient point-of-care bedside glucose testing: preliminary data on use of connectivity informatics to measure hospital glycemic control

BACKGROUND

Point-of-care (POC) bedside glucose (BG) testing and timely evaluation of its effectiveness are important components of hospital inpatient glycemic control programs. We describe a new technology to evaluate inpatient POC-BG testing and report preliminary results of inpatient glycemic control from 10 U.S. hospitals.

METHODS

We used the Remote Automated Laboratory System RALS-Tight Glycemic Control Module (TGCM) (Medical Automation Systems, Charlottesville, VA) connected to the RALS-Plus to extract and analyze inpatient POC-BG tests from 10 U.S. hospitals for a 3-month period. POC-BG measurements were evaluated in aggregate from all 10 facilities for intensive care unit (ICU), non-ICU, and ICU + non-ICU combined.

RESULTS

A total of 742,154 POC-BGs were analyzed. The combined (ICU + non-ICU) mean POC-BG was 159 mg/dL, compared with 146 mg/dL for the ICU and 164 mg/dL for non-ICU. The proportion of hypoglycemic values (<70 mg/dL) was low at 4%, but the percentage of measurements that would be considered hyperglycemic (>180 mg/dL) was high, with more than 30% of values in the non-ICU and 20% in the ICU being elevated.

CONCLUSIONS

POC-BG data can be captured through automated data management software and can support hospital efforts to evaluate and monitor the status of inpatient glycemic control. These preliminary data suggest that there is a need to conduct broad-based efforts to improve inpatient glucose management. Increasing hospital participation in data collection has the potential to create a national benchmarking process for the development of best practices and improved inpatient hyperglycemia management.

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.

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.