Glycemic control ‘a major vascular risk factor’ in Type 1 diabetes
MedWire News: Glycemic control shows a positive linear correlation with risks for both cardiovascular disease (CVD) and coronary heart disease (CHD) in patients with Type 1 diabetes, an observational study has found.
Importantly, there was no evidence of J-shaped risk curve, confirming the role of glycated hemoglobin (HbA1c) as a strong independent risk factor in Type 1 diabetes.
Katarina Eeg-Olofsson (University of Gothenburg, Sweden) and colleagues used the Swedish National Diabetes Register to identify 7454 patients with Type 1 diabetes who were aged 20-65 years and had a diabetes duration of 1-35 years. They were followed-up from 2002 to 2007.
Writing in the journal Diabetes Care, the researchers report that each 1% unit increase in baseline HbA1c was associated with a 31% increased risk for fatal or nonfatal CHD and a 26% increased risk for fatal or nonfatal CVD, after adjusting for a raft of other risk factors.
Additional adjustment for albuminuria lowered the hazard ratios only marginally, they note.
Indeed, fully adjusted 5-year event rates for CHD and CVD increased progressively with HbA1c levels between 5% and 12%. For instance, the risk for fatal/nonfatal CHD and for fatal/nonfatal CVD were, respectively, 41% and 37% lower in patients with HbA1c in the range 5.0-7.9% at baseline compared with those with an HbA1c in the range 8.0-11.9%.
The team believes that this is the first large epidemiologic study to demonstrate a clear association between glycemic control and CHD risk in Type 1 diabetes.
"This observational study… demonstrates a strong independent effect of increased baseline or updated mean HbA1c values on risks of CHD and CVD, with no sign of a J-shaped curve at lower HbA1c values even with longer diabetes duration," they conclude.
"This emphasizes the role of HbA1c as a strong independent risk factor in Type 1 diabetes."
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By Joanna Lyford