The Diabetes Control and Complications Trial (DCCT) and its observational follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) demonstrated the dominant role of glycemia, second only to age, as a risk factor for a first cardiovascular event in type 1 diabetes (T1D). The study investigated the association between established risk factors and the total cardiovascular disease (CVD) burden, including recurrent events.

      CVD events in 1,441 DCCT/EDIC participants were analyzed separately by type such as CVD death, acute myocardial infarction, stroke, silent MI, angina, percutaneous transluminal coronary angioplasty/coronary artery bypass graft (PTCA/CABG), and congestive heart failure (CHF) or as composite outcomes (CVD or major adverse cardiovascular events (MACE). Proportional rate models and conditional models assessed associations between risk factors and CVD outcomes.

      Over a median follow-up of 29 years, it was observed that 239 participants had 421 CVD events, and 120 individuals had 149 MACE. Age was found to be the strongest risk factor for acute MI, silent MI, stroke, and PTCA/CABG, while glycemia was the strongest risk factor for CVD death, CHF, and angina, second strongest for acute MI and PTCA/CABG, third strongest for stroke, and not associated with silent MI. It was also observed that HbA1c was the strongest modifiable risk factor for a first CVD event (CVD: HR 1.38 [95% CI 1.21, 1.56] per 1% higher HbA1c; MACE: HR 1.54 [1.30, 1.82]) and also for subsequent CVD events (CVD: incidence ratio [IR] 1.28 [95% CI 1.09, 1.51]; MACE: IR 1.89 [1.36, 2.61]).

      Cardiovascular events are common yet unforeseen and difficult to prevent in patients with T1D. However, once sensed the presence of serious atherosclerosis, the challenge is to prevent a recurrence, which carries significant morbidity and mortality, even among individuals without diabetes. Age followed by mean HbA1c were the two strongest risk factors for all (i.e., considering an average effect over the first and subsequent events) CVD events and MACE in proportional rate models. Hence intensive glycemic management is recommended to lower the risk of initial CVD events in T1D.