Metabolic syndrome, diabetes mellitus, or both and cardiovascular risk in outpatients with or at risk for atherothrombosis

Background: The incidence of metabolic syndrome (MetS), diabetes mellitus (DM), and their coexistence is increasing but whether MetS increases cardiovascular risk beyond component risk factors is controversial.

Design: We compared the risk of cardiovascular death, myocardial infarction, or stroke among patients with MetS, newly detected DM, established DM, or coexistent MetS and DM in the global REduction of Atherothrombosis for Continued Health (REACH) registry.

Methods: Outpatients with or at risk for atherothrombosis were recruited between 1 December 2003 and 31 December 2004 and followed up to 4 years for cardiovascular events. Risk was compared in patients with or without MetS or DM after adjustment for age, sex, risk factors, vascular disease, fasting blood glucose, therapy, and region.

Results: Among 44,548 REACH participants, 17,887 (40%) were without MetS or DM; 6459 had MetS (15%); 12,059 had established DM (27%); 7503 had both (17%); and 640 had newly detected DM (1%). Presence of MetS was not associated with higher cardiovascular events (12.6%, adjusted HR 0.98, 95% CI 0.89-1.08). In addition, once DM was evident, patients with coexistent MetS had similar increased risk (16.1%, adjusted HR 1.33, 95% CI 1.21-1.47) as DM alone (16.7%, adjusted HR 1.36, 95% CI 1.24-1.48). Newly detected DM was associated with increased cardiovascular risk (18.5%, adjusted HR 1.26, 95% CI 1.02-1.57), similar to longstanding DM. MetS was associated with incident DM (adjusted OR 1.94).

Conclusions: In the REACH registry, presence of newly detected DM but not metabolic syndrome was associated with an increased risk of cardiovascular events.