This January 31, 2017 JAMA Viewpoint article examines whether Hemoglobin A1c should be used as an outcome (quality) measure

Type 2 diabetes and its complications are one of the most expensive issues facing U.S. healthcare.  An obvious goal is to reduce the number  and scope of diabetic complications which should in return improve diabetic’s quality and likely longevity.  The conventional thinking is strict blood sugar control is the answer and goal.

Since 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

Results from diabetes medications demonstrated different cardiovascular outcomes in patients with type 2 diabetes casting further doubt that HbA1c is a good measure as a surrogate of predicting  diabetic complications .  Also several studies showed that some drugs notably, empagliflozin and liraglutide  decreased cardiovascular events and mortality regardless of blood sugar control.

Subsequently, 3 major clinical trials demonstrated that lowering HbA1c levels to less than 7% of total hemoglobin was not associated with cardiovascular benefits compared with less intensive glycemic control.Moreover, intensive glucose control had minimal, if any, effects on hard microvascular complications, such as vision loss or renal failure. this was published in the AHA publication Circulation on August 23, 2016

Unfortunately, the article argues that Hemoglobin A1c should not be used as a quality measure when looking at a measure to decrease diabetic complications.  Unfortunately the authors end  without suggesting an alternative outcome or quality measure for diabetesQualitQua.

Source: Hemoglobin A1c as an Outcome for Studies of Diabetes | Endocrinology | JAMA | The JAMA Network