Does Diabetes Mellitus Abolish the Beneficial Effect of Primary Coronary Angioplasty on Long-term Risk of Reinfarction After Acute ST-Segment Elevation Myocardial Infarction Compared With Fibrinolysis? (A DANAMI-2 Substudy)

Little is known about the effect of diabetes mellitus on long-term clinical outcome after primary percutaneous coronary intervention (pPCI) compared with fibrinolysis in patients who have acute ST-elevation myocardial infarction. We analyzed 3-year clinical outcome in diabetic patients and nondiabetic patients who had been randomized to fibrinolysis or pPCI in the DANAMI-2 trial to compare long-term clinical outcome. The primary end point was a composite of death, clinical reinfarction, or disabling stroke. Median follow-up was 3.8 years. Among 1,572 consecutive patients who had ST-elevation myocardial infarction and were randomized to pPCI or fibrinolysis, 173 (11.0%) had diabetes mellitus; 60 of these patients received metformin treatment and were excluded. After 3 years no difference was found between diabetic patients who underwent pPCI versus fibrinolysis (combined event p = 0.37, reinfarction p = 0.06 in favor of fibrinolysis), whereas pPCI was superior to fibrinolysis in nondiabetic patients (combined event p = 0.002, clinical reinfarction p <0.001). Three-year incidence of clinical reinfarction analyzed with Cox's regression showed that pPCI compared with fibrinolysis increased the relative risk of clinical reinfarction in diabetic patients (relative risk 2.57, 95% confidence interval 1.48 to 4.46, p <0.001) but decreased the risk in nondiabetic patients (relative risk 0.52, 95% confidence interval 0.36 to 0.74, p <0.001). In conclusion, from the DANAMI-2 trial we hypothesize that diabetes may abolish the beneficial effect of pPCI on long-term risk of clinical reinfarction.