Increased Glycemic Variability Is Independently Associated With Length of Stay and Mortality in Noncritically Ill Hospitalized Patients

OBJECTIVE To investigate the association between glycemic variability (GV) and both length of stay (LOS) and 90-day mortality in noncritically ill hospitalized patients. RESEARCH DESIGN AND METHODS This study retrospectively analyzed 4,262 admissions to the general medicine or surgery services during a 2 year period. Patients with point-of-care glucose monitoring and a minimum of two glucose values per day on average were selected. GV was assessed by SD and coefficient of variation (CV). Data were analyzed with linear and logistic multivariate regression analysis in separate models for SD and CV. Analysis was performed with generalized estimating equations to adjust for correlation between multiple admissions in some individual cases. RESULTS After exclusions, 935 admissions comprised the sample. Results of adjusted analysis indicate that for every 10 mg/dL increase in SD and 10–percentage point increase in CV, LOS increased by 4.4 and 9.7%, respectively. Relative risk of death in 90 days also increased by 8% for every 10-mg/dL increase in SD. These associations were independent of age, race, service of care (medicine or surgery), previous diagnosis of diabetes, HbA1c, BMI, the use of regular insulin as a sole regimen, mean glucose, and hypoglycemia occurrence during the hospitalization. CONCLUSIONS Our results indicate that increased GV during hospitalization is independently associated with longer LOS and increased mortality in noncritically ill patients. Prospective studies with continuous glucose monitoring are necessary to investigate this association thoroughly and to generate therapeutic strategies targeted at decreasing GV. Inpatient hyperglycemia is common, and it has been associated with increased morbidity and mortality in patients with and without diabetes (1–7). In the intensive care unit (ICU) setting, hypoglycemia has also been independently associated with a significant increase in mortality (8–10). Recently, a third metric of glucose control, known as glycemic variability (GV), has been proposed to be additionally implicated in the disease-associated process of dysglycemia (11). GV refers to fluctuations of blood glucose values around the mean and has been posited as a novel marker for poor glycemic control (12,13). In vitro and human studies suggest that high GV leads to greater oxidative stress than does sustained hyperglycemia (14,15). Studies of ICU patients have consistently demonstrated that increased GV is independently associated with higher mortality (16–19). Notably, results from a large multicenter study concluded that GV was a stronger predictor of ICU mortality than was mean glucose concentrations (20). Although there is no consensus as to the best method to determine GV in hospitalized patients, the use of SD of glucose values has been well validated by previous ICU studies (16,20). Coefficient of variation (CV) has also been suggested as a strong independent index for measuring GV because it corrects for mean glucose levels (21,22). Despite substantial scientific evidence from the ICU, no previous studies have investigated the association between GV and clinical outcomes in patients admitted to the general medical and surgical wards. The purpose of this study was therefore to investigate the association between GV and length of stay (LOS) and 90-day mortality in noncritically ill hospitalized patients. We hypothesize that increased GV in this setting is associated with increased LOS and mortality

A Decrease in Glucose Variability Does Not Reduce Cardiovascular Event Rates in Type 2 Diabetic Patients After Acute Myocardial Infarction: A reanalysis of the HEART2D study

To assess the effect of intraday glucose variability (GV) on cardiovascular outcomes in a reanalysis of Hyperglycemia and Its Effect After Acute Myocardial Infarction on Cardiovascular Outcomes in Patients With Type 2 Diabetes Mellitus (HEART2D) study data. Type 2 diabetic patients after acute myocardial infarction were randomized to an insulin treatment strategy targeting postprandial (PRANDIAL; n = 557) or fasting/interprandial (BASAL; n = 558) hyperglycemia. GV was calculated as mean amplitude of glycemic excursions (MAGE), mean absolute glucose (MAG) change, and SD. The PRANDIAL strategy resulted in an 18% lower MAG than BASAL (mean [SEM] difference 0.09 [0.04] mmol/L/h, P = 0.02). In addition, MAGE and SD were lower in the PRANDIAL group, however, not significantly. HbA(1c) levels and cardiovascular event rates were comparable between groups. A PRANDIAL strategy demonstrated lower intraday GV vs. a BASAL strategy with similar overall glycemic control but did not result in a reduction in cardiovascular outcomes. This does not support the hypothesis that targeting GV would be beneficial in reducing subsequent secondary cardiovascular event

Mean glucose during ICU admission is related to mortality by a U-shaped curve in surgical and medical patients: a retrospective cohort study

Lowering of hyperglycemia in the intensive care unit (ICU) is widely practiced. We investigated in which way glucose regulation, defined as mean glucose concentration during admission, is associated with ICU mortality in a medical and a surgical cohort. Retrospective database cohort study including patients admitted between January 2004 and December 2007 in a 20-bed medical/surgical ICU in a teaching hospital. Hyperglycemia was treated using a computerized algorithm targeting for glucose levels of 4.0-7.0 mmol/l. Five thousand eight hundred twenty-eight patients were eligible for analyses, of whom 1,339 patients had a medical and 4,489 had a surgical admission diagnosis. The cohorts were subdivided in quintiles of increasing mean glucose. We examined the relation between these mean glucose strata and mortality. In both cohorts we observed the highest mortality in the lowest and highest strata. Logistic regression analysis adjusted for age, sex, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, admission duration and occurrence of severe hypoglycemia showed that in the medical cohort mean glucose levels 8.4 mmol/l and in the surgical cohort mean glucose levels 9.4 mmol/l were associated with significantly increased ICU mortality (OR 2.4-3.0 and 4.9-6.2, respectively). Limitations of the study were its retrospective design and possible incomplete correction for severity of disease. Mean overall glucose during ICU admission is related to mortality by a U-shaped curve in medical and surgical patients. In this cohort of patients a 'safe range' of mean glucose regulation might be defined approximately between 7.0 and 9.0 mmol/

Sense and nonsense in sensors

Continuous subcutaneous glucose monitoring (CGM) is a developing technology in the treatment of diabetes mellitus. The first randomised controlled trials on its efficacy have been performed. In several studies, CGM lowered HbA1c in adult patients with suboptimally controlled type 1 diabetes mellitus, when selecting compliant patients who tolerate the device. However, as a preventive tool for hypoglycaemia, CGM has not fulfilled the great expectations. Increasing reimbursement of CGM is expected in the near future, awaiting studies on cost-effectiveness