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One in 10 heart attack patients has unrecognized diabetes
Key clinical point: Obtaining a HbA1c level in patients presenting with an acute MI who are not known to have diabetes will help identify those...
SAN FRANCISCO – About 17% of patients presenting with a myocardial infarction have undiagnosed diabetes, and their long-term mortality is similar regardless of what type of MI they had, according to analysis of data from the SWEETHEART registry.
The findings suggest that clinicians should "look for pathologic glucose metabolism in cardiac patients to identify those at high risk for subsequent events," Dr. Anselm K. Gitt said in an interview at the annual scientific sessions of the American Diabetes Association.
Dr. Anselm K. Gitt
Similar findings were first documented in the Euro Heart Survey Programme of the European Society of Cardiology (ESC), according to Dr. Gitt, a cardiologist at Klinikum Ludwigshafen, Germany. Those findings led to the first common guidelines of cardiologists and diabetologists in Europe (ESC and the European Association for the Study of Diabetes), which recommended the routine use of oral glucose tolerance testing (OGTT) in cardiac patients," he said. "SWEETHEART was the first registry documenting the application of these recommendations in clinical practice."
For the observational study, which was carried out at 30 sites in Germany from October 2007 to September 2009, researchers enrolled 2,767 consecutive patients with ST-segment MI (STEMI) or non-STEMI (NSTEMI) to identify newly diagnosed cases of diabetes mellitus and to document outcomes. In patients without DM, the researchers performed OGGT at day 4 after the MI and went on to examine the impact of known and newly diagnosed DM on 3-year outcomes.
Dr. Gitt reported that OGTT detected new DM in 16% of STEMI patients and in 17.8% of NSTEMI patients. Patients with newly diagnosed DM were younger, compared with those who had known DM (a mean age of 66 years vs. 70 years, respectively, among STEMI patients, and a mean of 70 vs. 72 years among NSTEMI patients). They also had fewer concomitant diseases and fewer prior cardiovascular interventions such as percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery.
Three-year mortality was similar in the newly diagnosed DM patients (11% and 13.9% for STEMI patients and NSTEMI, respectively). In the patients with known diabetes, the rates were also similar, at 22.6% and 21%, albeit significantly higher than in the newly diagnosed patients. The proportion of major adverse cardiac and cerebrovascular events at 3 years was also similar among the newly diagnosed DM patients with STEMI and NSTEMI, at 16.8% and 17.9%, and again similar in the known DM group (28.5% and 28.7%) but significantly higher than the newly diagnosed group.
The findings are akin to those of a study recently presented at the American Heart Association’s Quality of Care and Outcomes Research conference, which showed a lower percentage of undiagnosed diabetes (10%) in similar circumstances. In that study, however, hemoglobin A1c was used as a screening tool for previously unknown diabetes. HbA1c "is only the first step of screening," emphasized Dr. Gitt, who was not involved in the study. "OGTT has a much higher sensitivity than HbA1c."
Regarding the clinical implications of the SWEETHEART findings, Dr. Gitt said that "as a cardiologist, I would say we should treat [STEMI and NSTEMI high-risk] patients more stringently to the guideline-recommended targets for blood pressure and also for lipid control. Of course, we have to treat the diabetes, although we know that glucose control doesn’t alter mortality."
The study was supported by an unrestricted grant from Sanofi and Roche Diagnostics. Dr. Gitt disclosed that he is a member of Sanofi’s advisory board.
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