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Low 25-OH vitamin D levels have been associated with an increased rate of cardiovascular events as well as many markers of cardiovascular disease, including hypertension, increased vascular resistance, increased left ventricular mass index, and coronary calcification. Records were reviewed for 16,871 patients hospitalized with acute myocardial infarction from January 2000 to December 2005 who had at least one glucose measurement in the first 24 h. Data included both fingerstick and venous blood glucose measurements obtained throughout the hospitalizations. Using logistic regression models and C indexes, three metrics of glucose control (mean glucose, time-averaged glucose, hyperglycemic index), each evaluated over three time windows (first 24 h, 48 h, entire hospitalization), were compared with admission glucose for their ability to discriminate hospitalization survivors from nonsurvivors.

Findings. An analysis was performed of data from a large database that included 40 participating medical centers. Records were reviewed for 16,871 patients hospitalized with acute myocardial infarction from January 2000 to December 2005 who had at least one glucose measurement in the first 24 h. Data included both fingerstick and venous blood glucose measurements obtained throughout the hospitalizations. Using logistic regression models and C indexes, three metrics of glucose control (mean glucose, time-averaged glucose, hyperglycemic index), each evaluated over three time windows (first 24 h, 48 h, entire hospitalization), were compared with admission glucose for their ability to discriminate hospitalization survivors from nonsurvivors. All average glucose metrics performed better than admission glucose. The ability of models to predict mortality improved as the time window increased (C indexes for admission, mean 24 h, 48 h, and hospitalization glucose were 0.62, 0.64, 0.66, 0.70; P = 0.0001). Mortality rates increased with each 10-mg/dl rise in mean glucose ≥120 mg/dl (odds ratio [OR] 1.8, P = 0.003 for glucose 120 to <130 mg/dl) and with incremental decline <70 mg/dl (OR 6.4, P = 0.01 vs. glucose 100 to < 110 mg/dl). The slope of these relationships was steeper in patients without diabetes.

Significance. Hyperglycemia on admission is associated with an increased mortality in patients with acute myocardial infarction. Multiple "glucometrics" for identifying inpatients at risk for poor outcomes have been proposed. This study indicates that measures of persistent hyperglycemia throughout hospitalization appear to be better predictors of mortality than admission glucose. It remains unknown whether reducing glucose levels will improve outcomes.

Clinical impact. Patients with elevated glucose values in the setting of myocardial infarction, especially those without previously diagnosed diabetes, have an increased mortality risk. When hypoglycemia or hyperglycemia is noted, clinicians should consider the patient to be high risk and provide care with this in mind.