Background:The risk of myocardial infarction (MI) in type 2 diabetes (T2D) is 2-3 fold higher than the general population. Despite extensive diabetes literature documenting the relative risk of MI, there is less data on the association between the age at T2D diagnosis and expected time course to sustaining a MI^1,2.

Aim: To investigate the relationship between age at T2D diagnosis and duration of diabetes prior to MI.

Methods:The Royal Melbourne Hospital (RMH) cardiology database (n=7000, 2001-2012) was used to identify T2D patients with their first MI. The RMH diabetes database (n=5000, 1998-2012) was then accessed to confirm diabetes type and diagnosis date. Data from patients with T2D for a minimum of 10 years were analysed. 

Results: The cardiology database identified 2075 patients with MI; 665 (32%) had diabetes. Of the diabetes and MI group, 210 patients were identified in the diabetes database but 118 were excluded (due to T1D, <10y follow-up of diabetes or recurrent MI presentation with date of first MI not recorded). Thus data were available in 92 T2D patients (70% male).  In this subgroup, mean age at diagnosis of T2D was 50±24, mean age at MI was 68±20, hence a mean 18±17 period between the diagnosis of T2D and MI. Younger onset T2D developed MI at a younger age (Figure 1A) but had a greater duration to MI (Figure 1B). In T2D diagnosed before age 50 (n=44, age 41±14) versus after age 50y (n = 48, age 60±14) there was a significant greater time to MI (mean 22±19 vs 13±6, p<0.0001). 

Conclusions: In this cohort, the mean duration to MI after diagnosis of diabetes was 18 years. Despite the notion that diabetes is a high risk condition for MI, the window for therapeutic intervention in T2D may be greater than perceived, especially in younger patients.