Introduction: Admission blood glucose (BG) level is a predictor of mortality in patients with ST-segment elevation myocardial infarction (STEMI). However, limited data are available relating admission BG to mortality in patients with STEMI complicated by cardiogenic shock, and it is not known whether diabetic status has an independent effect on this relationship.
Methods: Between November 2005 and September 2010, 816 STEMI patients with cardiogenic shock were enrolled in a nationwide, prospective, multi-center registry; 239 (29.3%) had diabetes mellitus (DM). Patients were categorized according to BG levels at admission: <7.8, 7.8-10.9, 11.0-16.5 and ≥ 16.6 mmol/L. The primary outcome was 30-day mortality. The added values of BG to the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) scores were assessed by receiver operating characteristic curves and integrated discrimination improvement analyses.
Results: Thirty-day mortality was higher in patients with higher admission BG (20.4%, 23.3%, 39.8%, and 43.1% p < 0.001). Among non-diabetic patients, 30-day mortality was predicted by TIMI scores with a c-statistic of 0.615 (95% confidence interval [CI], 0.561-0.662) and GRACE scores with a c-statistic of 0.652 (95% CI, 0.604-0.695). Incorporation of admission BG increased the c-statistic for TIMI score to 0.685 (95% CI, 0.639-0.720, p < 0.001) and GRACE score to 0.708 (95% CI 0.664-0.742, p < 0.001). Additional predictive values for BG were not observed for diabetes. Integrated discrimination improvements (TIMI vs. additional BG and GRACE vs. additional BG) were 0.041 (p < 0.001) and 0.039 (p < 0.001) in non-diabetic patients.
Conclusions: In a cohort of patients with STEMI complicated by cardiogenic shock, admission BG was an independent predictor of increased risk of mortality only among patients without DM.