Glycemic Control and Cardiovascular Outcomes in Diabetes

While type 1 Diabetes Mellitus (DM) is characterized by insulin deficiency due to pancreatic beta cell destruction, type 2 DM is characterized by a state of long standing insulin resistance (IR), compensatory hyperinsulinemia and varying degrees of elevated plasma glucose (PG), associated with clustering of cardiovascular (CV) risk and development of macrovascular disease prior to diagnosis of DM. Coronary artery disease (CAD) accounts for 70% of mortality and morbidity in patients with diabetes. Studies made in diabetes care have helped prevent or reduce microvascular complications in type 1 and 2 diabetes. However the same cannot be said about macrovascular disease. Despite all data concerning the association of diabetes and cardiovascular disease (CVD), the exact mechanism by which diabetes is linked to atherosclerosis is incompletely understood, this is especially true in case of hyperglycemia. The positive effect of intensive glucose management in comparison to non intensive glucose control is far from proven. DCCT and UKPDS studies have shown that while a glycemic control is important for reaching long term macrovascular complications, early glucose control is far more rewarding (metabolic memory). Later trials like ACCORD, ADVANCE and VADT don't advocate tight glycemic control. In fact, ACCORD trial has shown increased mortality with tight glucose control. Tight glucose control may be beneficial in selected patients with short disease duration, long life expectancy and no CVD. In critically ill patients a blood glucose target of 140-180 mg% is fairly reasonable and achievable. The ESC/EASD guidelines of October 2013, Iike those of ADA, AHA and ACC continue to endorse a treatment target for glucose control in diabetes of HbAlc <7%, based predominantly on microvascular disease with acknowledged uncertainty regarding the effect of the intensive glucose control on CVD risk. Management of hyperglycemia in diabetics should not be considered in isolation; diabetics require multifactorial intervention for hypertension, dyslipidemia and microalbuminuria besides hyperglycemia. In fact combined use of antihypertensives, aspirin and lipid lowering agent makes it difficult to discern salutary effects of anti hyperglycemic therapy.