Glycemic Control and Variability for Congestive Heart Failure Exacerbation

High glucose as well as fluctuations (rapid swings) in blood glucose can contribute to severe hospital complications and even death.

High glucose as well as fluctuations in blood glucose can contribute to severe hospital complications and even death. Studies also suggest that heart failure patients who have high glucose or diabetes do not live as long as patients with normal glucose. Glucose fluctuations have not been well-studied in patients with heart failure. In this study, we will determine whether better control of blood sugar fluctuations in the hospital improve outcomes. We will enroll 80 patients with severe heart failure and divide them into 2 groups. We will use intravenous (given through the vein) insulin to lower blood sugar levels in group 1, and insulin injections (under the skin) in group 2. We will determine whether intravenous insulin improves blood markers of inflammation, changes in vital signs, and other tests that predict mortality in patients with heart failure.

High frequency heart rate variability (HF HRV)is a measure of cardiac autonomic tone. Electrocardiographic measures were obtained using a Bionex system (Mindware, Gahanna, OH). The electrocardiogram was performed in the standard lead II configuration. Software (Mindware, Gahanna, OH) was used to derive HF HRV. HF HRV was calculated using power spectral analysis.

Pre-ejection period (PEP) is the time between the onset of electrical depolarization of the ventricle and the opening of the aortic valve, a measure of sympathetic tone. It is obtained noninvasively using cardiac impedance obtained using a Bionex system (Mindware, Gahanna, OH). PEP is measured in milliseconds; lower values reflect higher sympathetic tone.

High sensitivity C-reactive Protein (hs-CRP) is a measure of inflammation. hsCRP (range 0-15 mg/L) was performed using Immunlite 1000 assay (Siemens; Erlangen, Germany).

Laboratory analyses were performed by the study institution's Clinical Research Center using standard commercial kits

Quality of Life was measured using the Minnesota Living with Heart Failure Questionnaire, which is a 21 question survey that uses a likert scale of 0-5. Each item asks over the past 4 weeks whether they have had a particular symptom of heart failure and to classify the response as no symptoms (0) to having the symptom very much (5). Responses are summed for a total score (0-105).

GLI is a measure of glycemic variability. GLI is the sum of the square of the difference between successive glucose measurements divided by the difference in time between measurements

Inclusion Criteria: Age 18 and above Admitted (less than 48 hours) to the with worsening heart failure Hyperglycemia or diabetes. Hyperglycemia is defined as blood glucose greater than 150 mg/dL on at least 2 occasions separated by at least 4 hours apart, insulin use, or HbA1c >6.5%. Exclusion Criteria: Type 1 diabetes Receiving comfort care measures only Hospital stay expected to be less than 2 days Pregnancy Prisoners Participation in the study on prior hospitalizations Acute myocardial infarction within 3 months End stage renal or liver disease