More than 400,000 men, women
The researchers enrolled men and women aged 40-69 between 2006 to 2010 who were living in England, Scotland, and Wales. After excluding people with type 1 diabetes or those whose A1c data were missing, the current study included 427,435 people (46% of whom were men).
The participants were classified as having low-normal A1c (< 35 mmol/mol or < 5.5%), normal A1c (35-41 mmol/mol or 5.5%-5.9%), prediabetes (42-47 mmol/mol or 6.0%-6.4%), undiagnosed diabetes (≥ 48 mmol/mol or ≥ 6.5%), or diagnosed type 2 diabetes (medical history and in receipt of glucose-lowering medication).
The researchers determined the incidence of six CVD outcomes during a median 11.8-year follow-up: coronary artery disease, atrial fibrillation, deep vein thrombosis, pulmonary embolism, stroke, and heart failure.
Few participants (5%) had any of these outcomes prior to study enrollment.
During the follow-up, there were 51,288 incident CVD events.
After adjustment for age, compared to having normal A1c, having prediabetes or undiagnosed diabetes was associated with an increased risk of CVD for women and men (hazard ratio [HR], 1.30-1.47).
Among individuals with diagnosed type 2 diabetes, the age-adjusted risk of CVD was greater for women (HR, 2.00) than for men (HR, 1.55).
After further adjustment for clinical and lifestyle factors, especially obesity and antihypertensive or statin use, the risk of CVD decreased and became similar among men and women. The fully adjusted HR for CVD was 1.17 for women and 1.06 for men with diagnosed diabetes.
Compared with having normal A1c, women and men with low-normal A1c were at decreased risk of CVD (HR, 0.86 for both).
The study was funded by Diabetes UK and the British Heart Foundation. Dr. Rentsch and Dr. Storey have disclosed no relevant financial relationships. The disclosures of the other study authors are listed in the original article.
A version of this article appeared on Medscape.com.