To what extent should we lower HbA1c in diabetic subjects?

Current recommendations regarding glycemic control suggest that HbA(1c) should be lower than 6.5%. This is supported by data regarding microvascular disease, namely retinopathy rather than nephropathy. The question is not completely solved regarding cardiovascular diseases, where a strategy of very low HbA(1c) ("the lower the better") is expected to be effective. Some ongoing studies will help to answer these unsolved questions.