January 26, 2017
Is Hemoglobin A1c the Right Outcome for Studies of Diabetes?
JAMA. Published online January 26, 2017. doi:10.1001/jama.2017.0029
The goals of treatment of type 2 diabetes are to reduce the risk of diabetic complications and, as a result, improve the quality and, possibly, duration of life. For several decades, authoritative guidelines instructed clinicians to strictly control glucose levels of patients with diabetes to accomplish these goals. In addition, in the 1990s, the US Food and Drug Administration (FDA) began to approve drugs for the treatment of diabetes based on hemoglobin A1c (HbA1c) levels as the outcome. The prevailing concept was that risk reduction could be achieved by a clinical focus on reaching target values of HbA1c, agnostic to the strategies used. This concept, analogous to early notions about lipid lowering, persisted despite the failure of trials evaluating tight glycemic targets, as assessed by HbA1c levels, to reduce the risk of heart disease or improve survival.1