Poor outcomes have been associated with elevated blood glucose levels in patients who were admitted to the hospital in critical condition or had acute myocardial infarction. This association has been shown in patients with and those without diabetes. In patients with heart failure, diabetes is an independent predictor of poor outcome. However, the consequences of high blood glucose levels in patients who do not have diabetes are unknown. Barsheshet and associates assessed the impact of high glucose levels on outcomes in patients without diabetes who were admitted to the hospital with heart failure to determine whether this variable could be used as a prognostic indicator.
The study used data collected over two months on patients admitted to one of 25 public hospitals for acute heart failure, acute exacerbation of chronic heart failure, or chronic heart failure. The diagnostic criteria for heart failure were symptoms consistent with heart failure and objective evidence of cardiac dysfunction at rest. Patients were excluded from the analysis if they had chronic stable heart failure but were admitted for noncardiovascular reasons, or if they had diabetes (i.e., had a history of diabetes, had a blood glucose level on admission of 200 mg per dL [11.1 mmol per L] or greater, or were taking diabetes medications on admission or discharge). Mortality information on patients was gathered for one year after their hospitalization.
There were 1,122 patients included in the study. Patients whose admission blood glucose level was in the highest tertile had a significantly higher in-hospital mortality rate than those in the first or second tertiles. An increase of 18 mg per dL (1.0 mmol per L) in blood glucose level was associated with a 31 percent increase in in-hospital mortality (adjusted odds ratio = 1.31) and a 12 percent increase in 60-day mortality (adjusted hazard ratio = 1.12). These were significant increases compared with patients who had normal blood glucose levels. The significance persisted when patients with acute myocardial infarction were excluded from the analysis. The six- and 12-month mortality rates were similar for patients who had elevated blood glucose levels and those with normal levels.
The authors conclude that high blood glucose levels correlate with increased inhospital and 60-day mortality rates in patients without diabetes admitted to a hospital for heart failure. They add that future studies need to be performed to determine whether blood glucose control may improve outcomes in patients with heart failure who do not have diabetes, as has been demonstrated in patients with acute myocardial infarction and in critically ill patients.