BENEFIT AND RISKS OF ANTIDIABETIC TREATMENT IN PATIENTS WITH CORONARY ARTERY DISEASE AND HEART FAILURE


Christoph H. Saely, M.D., VIVIT Institute, Academic Teaching Hospital, Feldkirch, Austria

Diabetes mellitus is a paramount risk factor both for coronary artery disease (CAD) and heart failure, and the prevalence of diabetes among patients with CAD or heart failure is high. While better glucose control epidemiologically is associated with a lower incidence of cardiovascular events, lowering blood glucose failed to lower the incidence of macrovascular diabetes complications, i.e. of atherosclerotic cardiovascular disease in multiple trials, in particular among patients with established CAD. Aggressive glucose lowering even was associated with increased mortality in one landmark trial. Pathophysiologically, hypoglycemia poses patients with CAD or heart failure at an increased risk of cardiac arrhythmia. With regard to specific anti-diabetic agents, data from randomized trials point towards a favorable impact of pioglitazone and metformin on cardiovascular event risk. Because of signals that rosiglitazone confers an increase in cardiovascular event risk, the FDA required that new anti-diabetic drugs are tested for cardiovascular safety in adequately powered trials; for example the cardiovascular safety of the DPP-4 inhibitors alogliptin and saxagliptin has recently been demonstrated. Pioglitazone increases fluid retention and therefore is contraindicated in patients with heart failure. Even though metformin is formally contraindicated in patients with heart failure, the prognosis of heart failure patients on metformin in registries is better than of those on other anti-diabetic drugs. Importantly, the prevention of microvascular diabetes complications is important also in CAD or heat failure patients. Like for other patients, the American Diabetes Association therefore recommends an HbA1c goal of <7.0% in these patients.