Association of dysglycemia and all-cause mortality across the spectrum of coronary artery disease

Objective: To assess the association between fasting plasma glucose (FPG) and all-cause mortality across the spectrum of coronary artery disease (CAD).

Patients and methods: The study included 18,999 patients during a study period of April 1, 2004, through October 31, 2010. The primary end points were in-hospital and follow-up all-cause mortality. According to the quartiles of FPG levels, patients were categorized into 4 groups: quartile 1, less than 5.1 mmol/L; quartile 2, 5.1 to less than 5.9 mmol/L; quartile 3, 5.9 to less than 7.5 mmol/L; and quartile 4, 7.5 mmol/L or greater. The conversion factor for units of plasma glucose is 1.00 mmol/L equals 18 mg/dL. Presented as mg/dL, the 4 quartile ranges of plasma glucose concentrations used in our data analysis are ≤90.0 mg/dL, 90.1-106.0 mg/dL, 106.1 mg/dL-135.0 mg/dL and ≥135.1 mg/dL. Quartile 1 was recognized as the lower glycemic group, quartiles 2 and 3 as the normoglycemic groups, and quartile 4 as the higher glycemic group.

Results: In patients with acute myocardial infarction, all-cause mortality for the dysglycemic groups was higher than for the normoglycemic groups: in-hospital mortality for quartiles 1, 2, 3, and 4 was 1.0%, 0.9%, 0.2%, and 1.5%, respectively (P=.001); follow-up mortality for quartiles 1, 2, 3, and 4 was 1.7%, 0.9%, 0.3%, and 1.8%, respectively (P<.001). In patients with stable CAD, no significant differences in mortality were found among groups. However, in patients with unstable angina pectoris, the normoglycemic groups had lower follow-up mortality and roughly equal in-hospital mortality compared with the dysglycemic groups. After adjusting for confounding factors, this observation persisted.

Conclusion: The association between lower FPG level and mortality differed across the spectrum of CAD. In patients with acute myocardial infarction, there was a U-shaped relationship. In patients with stable CAD or unstable angina pectoris, mildly to moderately decreasing FPG level was associated with neither higher nor lower all-cause mortality.