On the basis of these 2 large controlled trials, along with smaller studies and numerous epidemiological reports, the consistent findings related to microvascular risk reduction with intensive glycemic control have led the American Diabetes Association (ADA) to recommend an A1c goal of 7% for most adults with diabetes, 6 recognizing that more or less stringent goals may be appropriate for certain patients. Whereas many epidemiological studies and meta-analyses7, 8 have clearly shown a direct relationship between A1c and CVD, the potential of intensive glycemic control to reduce CVD events has been less clearly defined. In the DCCT, there was a trend toward lower risk of CVD events with intensive control (risk reduction, 41%; 95% CI, 10 to 68), but the number of events was small. However, 9-year post-DCCT follow-up of the cohort has shown that participants previously randomized to the intensive arm had a 42% reduction (P 0.02) in CVD outcomes and a 57% reduction (P 0.02) in the risk of nonfatal myocardial infarction (MI), stroke, or CVD death compared with those previously in the standard arm. 9

The UKPDS of type 2 diabetes observed a 16% reduction in cardiovascular complications (combined fatal or nonfatal MI and sudden death) in the intensive glycemic control arm, although this difference was not statistically significant (P 0.052), and there was no suggestion of benefit on other CVD outcomes such as stroke. However, in an epidemiological analysis of the study cohort, a continuous association was observed such that for every percentage point of lower median on-study A1c (eg, 8% to 7%) there was a statistically significant 18% reduction in CVD events, again with no glycemic threshold.