The benefits of treatment for diabetes needs to be weighed against the risks, especially hypoglycaemia. In general, the greatest benefits are seen by reducing HbA1c down to less than 7%. While targeting HbA1c less than 6.5% may give additional benefits in terms of reducing the risk of diabetic kidney disease and retinopathy, the benefits for cardiovascular risk reduction is less clear cut. This is likely due to the increased risk of hypoglycaemia, which in turn increases cardiovascular risk as HbA1c targets get even lower. Current guidelines recommend HbA1c target of less than 7% for most people with diabetes, while aiming for less than 6.5% if this can be safely achieved without hypoglycaemia or other treatment-related side effects.
Some high-risk individuals may develop significant hypoglycaemia and side effects even at higher HbA1c targets. This is especially true for the elderly, frail, and those with advanced diabetes or diabetes complications. People from a disadvantaged social background with limited monitoring resources may also be at higher risk for hypoglycaemia. For these groups of high-risk individuals, a higher HbA1c target may be reasonable, typically ranging from 7.5% to 8%.
Approach to individualized HbA1c targets. Image from American Diabetes Association (click on image to zoom).
Blood pressure targets have also been extensively studied in clinical trials. Current evidence suggest that a blood pressure of less than 140/80 mmHg is optimal for cardiovascular risk reduction. Lower blood pressure target of less than 130/80 mmHg may be considered for people at higher cardiovascular risk.
Similarly, treatment targets for cholesterol lowering depend on the cardiovascular risk profile of a person. Most people with diabetes should receive cholesterol-lowering treatment at 40 years of age and above, or at an earlier age after discussion with their diabetes care providers. The target for LDL-cholesterol lowering is less than 2.6 mmol/L for most people with diabetes, less than 1.8 mmol/L for those with higher cardiovascular risk, and even lower for those with established cardiovascular diseases. However, these treatment targets need to be balanced with the risk of treatment side effects, which may vary between different individuals.