coronary risk equivalent? Systematic review and meta-analysis.

Do patients with diabetes and no history of myocardial infarction (MI) have similar risk for coronary artery disease (CAD) events as patients with previous MI and no diabetes? Review scope Included studies compared risk for CAD events in patients with diabetes and no MI and patients with previous MI and no diabetes. Outcomes were fatal or nonfatal MI. Commentary In recent years, evidence from large cohort studies, including the Finnish study by Haffner and colleagues, has led to the concept that diabetes mellitus (DM) is a coronary risk equivalent (1, 2). In trials of acute coronary syndromes, patients with DM have increased risk for subsequent cardiovascular events. Therefore, experts have argued that patients with DM and no coronary events should be treated in a similar fashion to their counterparts with CAD. To evaluate this concept, Bulugahapitiya and colleagues evaluated 14 cohorts in a systematic overview and found that patients with DM and no history of MI had lower risk for CAD events than patients without DM and a history of MI. The discrepancies between this meta-analysis and the Haffner study can be explained by the fact that diabetes, as a cardiovascular process, is complex. Simply, not all primary prevention patients with DM are the same. The cardiovascular prognosis for type 2 DM depends on several variables, including age, duration of DM, degree of opti-mization of serum lipid levels and blood pressure, and presence of other comorbid conditions, such as nephropathy. Because type 2 DM is often accompanied by ≥ 1 other traditional risk factor, some rationale exists for treating patients with DM aggressively. Based on national guidelines over the past decade, we have wit-nessed the advent of statin therapy for all patients with type 2 DM regardless of low-density lipoprotein cholesterol levels, a