One-year mortality in elderly adults with non-ST-elevation acute coronary syndrome: effect of diabetic status and admission hyperglycemia.

OBJECTIVES

To determine whether type 2 diabetes mellitus and hyperglycemia on admission should be considered independent predictors of mortality in elderly adults with acute coronary syndrome (ACS).

DESIGN

Prospective cohort study.

SETTING

Twenty-three hospitals in Italy.

PARTICIPANTS

Individuals aged 75 and older with non-ST-elevation ACS (NSTEACS) (mean age 82, 47% female) (N = 645).

MEASUREMENTS

Diabetic status and blood glucose levels were assessed on admission. Hyperglycemia was defined as glucose greater than 140 mg/dL. Multivariable Cox proportional hazard regression was used to assess the potential confounding effect of major covariates on the association between diabetic status, admission glucose, and 1-year mortality.

RESULTS

A history of diabetes mellitus was found in 231 participants (35.8%), whereas 257 (39.8%) had hyperglycemia. Hyperglycemia was found in 171 participants with diabetes mellitus (70%) and 86 (21%) without diabetes mellitus. Participants with diabetes mellitus were significantly (P < .05) more likely to have had prior myocardial infarction and stroke and had lower ejection fraction and blood hemoglobin. Hyperglycemia was associated with lower (P < .05) ejection fraction and estimated glomerular filtration rate (eGFR). Diabetic status and hyperglycemia were associated with greater 1-year mortality according to univariate analysis (54 participants with diabetes mellitus died (23.4%), versus 66 (15.9%) without diabetes mellitus (hazard ratio (HR) = 1.5 95% confidence interval (CI) = 1.0-2.1), and 60 participants with hyperglycemia died (23.3%), versus 60 (15.5%) without hyperglycemia (HR=1.6; 95% CI = 1.1-2.2), but this association was not statistically significant after adjustment for ejection fraction, age, blood hemoglobin, and eGFR.

CONCLUSION

In elderly adults with NSTEACS, diabetes mellitus and hyperglycemia on admission are associated with higher mortality, mostly because of preexisting cardiovascular and renal damage.