Table 1:

Summary of observational studies reporting increased mortality with low HbA1c

Study	Design	Population	Cut off HbA1c*	Characteristics of patients with low HbA1c
Engoren et al, 2013	Prospective	Diabetics undergoing heart surgery	5.7%	Older, having myocardial infarctions, smokers, needed blood transfusions, and concomitant valve surgery.
Aguilar et al, 2009	Retrospective	Diabetics with heart failure	6.4%	Older, have chronic kidney disease, anemia and low cholesterol
Nichols et al, 2013, US	Prospective	Diabetics	6%	Older, more macrovascular complications, lower body mass index and lower blood pressure.
Currie et al, 2010, UK	Retrospective	Diabetics	6.4%	Insulin treated, older, more comorbidities and longer duration of diabetes.
Nicholas et al, 20	Case-control	Diabetics	6.5%	More prevalence of vascular disease, renal failure, malnutrition, smoking and weight loss.
Monami et al, 2013	Case-control	Diabetics	6.5%	Insulin-treated, older, longer duration of diabetes and more comorbidity burden.
Colayco et al, 2011	Case-control	Diabetics	6.4%	More prevalence of cardiovascular comorbidities.
Carson, et al 2010	Prospective	General population	4.0%	Low cholesterol, high ferritin, low blood pressure and abnormal liver function.
Shurraw et al, 2011	Prospective	Diabetics with CKD	6.5	Older, high level of heart, lung, liver diseases, malignancy and dementia.
Ricks et al, 2012	Prospective	Diabetics on hemodialysis	6.9	Low body weight and increased markers of malnutrition and inflammation.