This population-based study compared the 7-year incidence of fatal and nonfatal MI among subjects with and without type 2 diabetes. A history of MI at baseline in either group was significantly associated with an increased incidence of fatal and nonfatal MI (P<0.001).
Subjects with neither diabetes nor prior MI had the best prognosis (3.5% incidence of MI); subjects with both diabetes and prior MI had the worst prognosis (45% incidence of MI).
Those patients with type 2 diabetes and no prior history of MI had intermediate survival rates, similar to patients without diabetes but with a history of MI (20.2% and 18.8%, respectively, after adjustments for age and sex). Coronary disease incidence rates were also similar between these two groups.
These findings suggest that all patients with diabetes should be treated as if they had prior MI, ie, should be treated aggressively.

Haffner SM, et al. N Engl J Med. 1998;339:229–234.