CHICAGO– Impaired fasting glucose was associated with a doubled risk of asymptomatic or unrecognized myocardial infarction during prospective follow-up of subjects without overt cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis.
The clinical relevance of this finding lies in previous work establishing that asymptomatic, unrecognized MIs are associated with a prognosis as serious as for symptomatic MIs.
“Because of the high prevalence of impaired fasting glucose, the implications of this finding may have ramifications for a large proportion of the adult population,” Dr. Richard B. Stacey observed at the American Heart Association Scientific Sessions.
The magnitude of the risk of unrecognized MI was associated with duration of exposure to abnormal blood glucose levels in the landmark population-based MESA study. Subjects with impaired fasting glucose (IFG) noted on at least three of five biannual examinations conducted over a 10-year period had an adjusted 1.97-fold greater risk of experiencing an unrecognized MI during that time, compared with MESA participants who had normal blood glucose, added Dr. Stacey of Wake Forest University in Winston-Salem, N.C.
He presented two new analyses from the MESA study. One was cross-sectional: Among 4,955 study participants with normal fasting glucose and 930 with IFG upon study enrollment, a baseline 12-lead ECG revealed a prior unrecognized MI in 1.4% of those with normal fasting glucose and 3.2% of those with IFG, a 2.3-fold increase. MESA participants were on average in their mid-60s, and none had clinical cardiovascular disease.
In a multivariate logistic regression analysis fully adjusted for demographics and the standard cardiovascular risk factors as well as body mass index and the use of antihypertensive and lipid-lowering medications, IFG was associated with a 1.63-fold increased risk of prior asymptomatic or unrecognized MI (P < .001).
The other, prospective, longitudinal analysis, included 872 subjects with baseline normal fasting glucose and 545 with IFG, none of whom had evidence of a prior unrecognized MI at entry. This analysis excluded individuals who developed diabetes mellitus, had a clinically recognized MI, or underwent coronary revascularization during follow-up. During 10 years of follow-up, 14.9% of the group who continued to have normal fasting glucose experienced an unrecognized MI, as did 23.8% of those with IFG at entry. The unrecognized MIs were detected either by the presence of pathologic Q waves or minor Q waves with ST-T abnormalities on ECG or by an MRI showing late gadolinium enhancement indicative of myocardial scar.
The MESA study is funded by the National Institutes of Health. Dr. Stacey reported having no financial conflicts.