Vijan and colleagues [1] used a Markov decision model to estimate the benefit of glycemic control with respect to the end points of blindness and end-stage renal disease in persons with type 2 diabetes without preexisting microvascular complications. They found that the benefit of glycemic control decreased with increasing age at diabetes onset.

The decrease in absolute risk resulting from decreased duration of diabetes permits risk stratification in determining a patient's target hemoglobin A_1c level, an approach used to design the Veterans Health Administration (VHA) Guidelines for Management of Diabetes Mellitus. Developed in collaboration with members of the Executive Committee of the National Diabetes Education Program, the VHA guidelines are available on the Internet (http://www.va.gov/health/diabetes/default.htm) and are to be used in all VHA facilities.

Participants in the guideline development concluded that a synthesis of the evidence, including key controlled trials [2], epidemiologic studies [3], and computer modeling [1, 4] supported the use of life expectancy and clinical microvascular discase as major determinants in setting a target value for glycemic control in an individual patient. Clinicians should still assess other factors, such as psychosocial issues and patient preferences, when negotiating a target with their patients.

The VHA guidelines suggest that patients who are likely to live only a few years might have a target hemoglobin A_1c level of about 0.09, whereas younger patients, especially those with microvascular changes, may benefit from a target value of 0.07. Many, perhaps most, patients will have a target of about 0.08.

With risk stratification and flexible individual assessment, the VHA guidelines consider both the likelihood of an absolute reduction in microvascular outcomes and the likelihood of safely achieving a given level of glycemic control in a particular patient. We believe that this approach provides the evidence that practitioners and patients need to make informed choices and strengthens clinicians' role in caring for their patients.