Onset Of Diabetes Higher In Patients Who Have Had Heart Attacks

Dr Dariush Mozaffarian, Harvard Medical School and Harvard School of Public Health, Boston, USA, Dr Roberto Marchioli, Consorzio Mario Negri Sud, Italy and colleagues studied 8291 Italian patients who had had a heart attack within the previous three months, and were free of diabetes. Incidence of new-onset diabetes and IGF were measured at 0.5, 1.0, 1.5, 2.5, and 3.5 years follow-up. Data for body-mass index, other risk factors, dietary habits, and medications were updated during the follow up, and a Mediterranean diet score was given to each patient based on their consumption of raw and cooked vegetables, fruit, fish and olive oil.

The researchers found one third of patients with a recent heart attack developed diabetes or IFG (blood glucose 6.1 mmol/L or more), during the 3.5 years of follow up; this rose to two-thirds when the lower IFG cut-off point of 5.6mmol/L or more blood glucose was used. Patients with a recent heart attack were up to four-and-a-half times more likely to develop diabetes (3.7%) compared with the general population (0.8-1.6%), and more than 15 times more likely to develop IFG (27.5% versus 1.5%).

Independent risk factors associated with new-onset diabetes or IFG included older age, high blood pressure, use of beta-blockers, lipid-lowering medications (protective), and diuretic use. Independent life-style risk factors included higher body mass index, (BMI), greater BMI gain during follow-up, current smoking (which increased risk by 60%), a lower Mediterranean dietary score, and wine consumption of more than one litre per day. Data for physical activity were unavailable, but people who could not perform exercise testing were at higher risk of both diabetes and IFG.

The authors conclude: “Our findings suggest that incidence of IFG and diabetes is high in the years after myocardial infarction, suggesting that acute myocardial infarction could be a pre-diabetes risk-equivalent….Our findings also suggest that smoking cessation, prevention of weight gain, and consumption of typical Mediterranean foods could substantially lower this risk, which has important implications for counselling patients soon after they have a myocardial infarction – an opportune time to institute lifestyle changes in patients motivated by a life-changing event.”

In an accompanying Comment, Dr Lionel Opie, Hatter Cardiovascular Research Institute, University of Cape Town, South Africa, says: “These findings further tie the knot between myocardial infarction and hyperglycaemia – each causes the other.” He adds that, of the lifestyle factors, “major interest lies in the potential protective effect of the Mediterranean diet.”