Intensive glycaemic control in type 2 diabetes mellitus: does it improve cardiovascular outcomes?

With growing urbanization and economic development, there is a rapid increase in the incidence of type 2 diabetes mellitus (T2DM) in India. T2DM is associated with 2-4 times higher risk for cardiovascular disease (CVD), including coronary artery disease, stroke and peripheral vascular disease. Several studies have shown the benefit of intensive glycaemic control in reducing the frequency of diabetic microvascular complications such as retinopathy and nephropathy. Results of long term follow up of patients with diabetes, who were enrolled in earlier trials, have shown that initial intensive glycaemic control led to a reduction in CVD outcomes when compared with standard therapy. However, it is unclear if intensive glycaemic control, aiming to reduce haemoglobin A1c to levels even lower than the current goal of <7%, will similarly lead to reduction in the rates of CVD. Recently, the results of 3 large, randomized controlled trials have been published, which suggest that in established T2DM with previous CVD or high risk of CVD, the benefits of intensive glycaemic control when compared with conventional good control, are minimal with regards to reduction of cardiovascular outcomes. Intensive therapy increases the risk of side-effects such as severe hypoglycaemia and weight gain. The implementation of such a therapy, with rigorous attention to frequent monitoring of blood glucose and visits to the physician, is not likely to be possible on a large scale, especially in a developing country such as India. The aim of management of patients with established T2DM should be to achieve the goal of good glycaemic control (haemoglobin A1c<7%), with avoidance of hypoglycaemia. It is equally, if not more important, to control other risk factors of CVD by paying greater attention to lifestyle measures (weight loss if overweight or obese, regular exercise, cessation of smoking), rigorous control of blood pressure (<130/80 mmHg) and low density lipoprotein (LDL) cholesterol (<100 mg/dl or <70 mg/dl if already diagnosed with CVD) and the prophylactic use of low dose aspirin as per current recommendations. A multifactorial approach targeting multiple cardiovascular risk factors is likely to be most effective in reducing CVD outcomes in T2DM.