Abnormal Fasting Glucose Increases Risk of Unrecognized Myocardial Infarctions in an Elderly Cohort

Objectives: To investigate glucose levels as a risk factor for unrecognized myocardial infarctions (UMIs).

Design: Cohort SETTING: Cardiovascular Health Study.

Participants: Individuals aged 65 and older with fasting glucose measurements (N=4,355; normal fasting glucose (NFG), n = 2,041; impaired fasting glucose (IFG), n = 1,706; DM: n = 608; 40% male, 84% white, mean age 72.4 ± 5.6).

Measurements: The relationship between glucose levels and UMI was examined. Participants with prior coronary heart disease (CHD) or UMI on initial electrocardiography were excluded. Using Minnesota codes, UMI was identified according to the presence of pathological Q-waves or minor Q-waves with ST-T abnormalities. Crude and adjusted hazard ratios (HRs) were calculated. Analyses were adjusted for age, sex, body mass index (BMI), hypertension, antihypertensive and lipid-lowering medication use, total cholesterol, high-density lipoprotein cholesterol, and smoking status.

Results: Over a mean follow-up of 6 years, there were 459 incident UMIs (NFG, n=202; IFG, n=183; DM, n=74). Participants with IFG were slightly more likely than those with NFG to experience a UMI (hazard ratio (HR)=1.11, 95% confidence interval (CI)=0.91-1.36, p = .30), and those with DM were more likely than those with NFG to experience a UMI (HR=1.65, 95% CI=1.25-2.13, p < .001). After adjustment HR for UMI in IFG those with IFG were no more likely than those with NFG to experience a UMI (HR=1.01, 95% CI=0.82-1.24, p = .93), whereas those with DM were more likely than those with NFG to experience a UMI (HR=1.37, 95% CI=1.02-1.81, p = .03). The 2-hour oral glucose tolerance test was not statistically significantly associated with UMI.

Conclusion: Fasting glucose status, particularly in the diabetic range, forecasted UMI during 6 years of follow-up in elderly adults. Further studies are needed to clarify the level of glucose at which risk is greater. J Am Geriatr Soc 67:43-49, 2019.