The Data Collection on Adverse Events of Anti-HIV Drugs (DAD) Study Group conducted a prospective observational study to investigate the association between combination antiretroviral therapy and the risk of myocardial infarction. The study enrolled 23,468 HIV-1-infected patients from 11 cohorts and followed them until February 2002. Over 36,199 person-years, 126 patients experienced myocardial infarction. The incidence of myocardial infarction increased with longer exposure to combination antiretroviral therapy (adjusted relative rate per year of exposure, 1.26 [95% CI, 1.12 to 1.41]; P<0.001). Other significant risk factors included older age, smoking, previous cardiovascular disease, and male sex. Higher total serum cholesterol levels, triglyceride levels, and diabetes were also associated with an increased risk. The study concluded that combination antiretroviral therapy was independently associated with a 26% relative increase in the rate of myocardial infarction per year of exposure during the first four to six years of use, but the absolute risk was low and must be balanced against the benefits of antiretroviral treatment.The Data Collection on Adverse Events of Anti-HIV Drugs (DAD) Study Group conducted a prospective observational study to investigate the association between combination antiretroviral therapy and the risk of myocardial infarction. The study enrolled 23,468 HIV-1-infected patients from 11 cohorts and followed them until February 2002. Over 36,199 person-years, 126 patients experienced myocardial infarction. The incidence of myocardial infarction increased with longer exposure to combination antiretroviral therapy (adjusted relative rate per year of exposure, 1.26 [95% CI, 1.12 to 1.41]; P<0.001). Other significant risk factors included older age, smoking, previous cardiovascular disease, and male sex. Higher total serum cholesterol levels, triglyceride levels, and diabetes were also associated with an increased risk. The study concluded that combination antiretroviral therapy was independently associated with a 26% relative increase in the rate of myocardial infarction per year of exposure during the first four to six years of use, but the absolute risk was low and must be balanced against the benefits of antiretroviral treatment.