For patients with diabetes who undergo percutaneous coronary intervention (PCI), drug-eluting stents (DES) reduce the risk of mortality, acute myocardial infarction (MI), and repeat revascularization compared with bare-metal stents (BMS). These 3-year findings from the Massachusetts Data Analysis Center Registry (Mass-DAC), which requires mandatory reporting and follow-up, reflect achievable treatment outcomes in the real-world clinical setting, researchers reported.

Findings from Mass-DAC are important because patients with diabetes have a higher prevalence of ischemic heart disease than the general population and account for approximately one-third of all patients who undergo PCI, said Laura Mauri, MD, MSc, Brigham and Women's Hospital, Boston, MA. In addition, PCI is associated with unique limitations in the diabetic population, such as a higher risk of restenosis, MI, and cardiac mortality.

Dr. Mauri presented results of the Mass-DAC trial, which were simultaneously published online in Circulation [Garg P et al. Circulation 2008].

The Mass-DAC analysis included data from all adults who underwent PCI in Massachusetts from April 1, 2003 through Sept. 30, 2004 and completed a 3-year follow-up (n=21,045). Of the 5051 patients with diabetes, 3341 received a DES and 1710 received a BMS. Patients who received both types of stent were excluded from the analysis.

Because Mass-DAC was an observational study in which patients were not randomly assigned to different treatment groups, several baseline characteristics differed in the 2 groups. Therefore, propensity score matching using 67 clinical variables was used to compare outcomes in the DES and BMS groups. The primary endpoints were mortality, MI, and target vessel revascularization after 3 years.

The unadjusted mortality rate was 14.4% for patients who received DES and 22.2% for those who received BMS. According to propensity score analysis, DES were associated with a 3.2% absolute reduction in the risk of death compared with BMS (17.5% vs 20.7%; p=0.02), a 3% absolute reduction in the risk of MI (13.8% vs 16.9%; p=0.02), and a 5.4% absolute reduction in the risk of target vessel revascularization (18.4% vs 23.7%; p<0.001; Figure 1).

Dr. Mauri noted that the mortality curves for the DES and BMS groups stayed roughly parallel from 6 months through 3 years. The durability of the restenosis benefit with the small but persistent survival benefit that was associated with DES suggests that they should be the preferred therapy in patients with diabetes, she concluded.