Approximately two-thirds of patients who experience an acute myocardial infarction (AMI) and have no prior history of diabetes have been shown to have dysglycemia when evaluated with either an oral glucose tolerance test (OGTT) or measurement of HbA1c, underscoring the importance of screening for diabetes in this population. These findings were published in the journal Cardiovascular Diabetology.

A single-center, observational cohort study was conducted among patients aged younger than 80 years who were admitted for AMI at the Department of Cardiology, Danderyd University Hospital, in Stockholm, Sweden, between  January 1, 2006, and December 31, 2013. Having initiated an implementation program to identify undetected dysglycemia and offer lifestyle advice to patients, researchers sought to explore the link between newly detected disturbances of glucose metabolism and long-term prognosis following AMI, as well as to compare the predictive value of OGTTs and HbA1c.

Prior to discharge from the hospital, participants were examined with an OGTT and an HbA1c measurement, and were classified as having normal glucose tolerance (NGT), prediabetes, or diabetes, based on diagnostic criteria of the American Diabetes Association. All patients were followed up for all-cause mortality until December 25, 2017, and for hospitalization for MI, ischemic stroke, or heart failure (HF) until December 31, 2014.


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Investigators used a nationwide, all-inclusive register to follow-up with patients for a mean of 4.8 years for incidence of the combined event (CE) of mortality or first MI, HF, or ischemic stroke. Among a total of 841 patients who were assessed with both an OGTT and an HbA1c measurement, 17% had NGT, 47%  had prediabetes, and 36% had diabetes, according to OGTT. The corresponding for values for HbA1c measurement were 38%, 55%, and 7%, respectively.

Results of the study showed that patients with newly diagnosed diabetes were older and had a higher BMI than those with NGT. Although an OGTT was not predictive of the CE, prediabetes identified by HbA1c measurement was associated with an increased risk for the CE (hazard ratio [HR], 1.31; 95% CI, 1.05-1.63) compared with normoglycemia. When the prognostic values of different glucose and HbA1c cut-offs were compared, only an HbA1c of 39 mmol/mol or greater was significantly associated with the CE (HR, 1.30; 95% CI, 1.05-1.61). Patients with prediabetes had poorer prognoses, with significantly higher risks for cardiovascular events and mortality

“Our findings seem to support the latest guidelines recommending to primarily use [fasting plasma glucose] and HbA1c in screening for diabetes after AMI and, only if needed, complement with an OGTT,” the researchers noted.

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference  

Karayiannides S, Djupsjö C, Kuhl J, et al. Long-term prognosis in patients with acute myocardial infarction and newly detected glucose abnormalities: predictive value of oral glucose tolerance test and HbA1c. Cardiovasc Diabetol. Published online June 14, 2021. doi:10.1186/s12933-021-01315-5