How does the prognosis of diabetes compare with that of established vascular disease? Insights from the Canadian Vascular Protection (VP) Registry

Background Diabetes mellitus is a major risk factor for atherosclerotic cardiovascular disease. In a large, prospective, practice-based registry (the Vascular Protection Registry), we enrolled patients with vascular disease and/or diabetes, and compared the following features between diabetic and non-diabetic participants: (1) risk factor profiles, (2) utilization of cardioprotective medications, and (3) cardiovascular outcomes in short-term follow-up. Methods Patients were enrolled by participating physicians practicing in family medicine or specialty practices across Canada. The primary outcome was a composite of the first occurrence of any of the following vascular events: myocardial infarction, unstable angina, coronary revascularization, stroke, transient ischemic attack, or death. Patients were stratified according to the presence or absence of cardiovascular disease and diabetes. Results In all, 3297 patients were available for analysis (972 [30%] with diabetes but no cardiovascular disease; 899 [27%] with both diabetes and cardiovascular disease; and 1425 [43%] with cardiovascular disease but no diabetes). Most of the measured risk factors were worse for patients with diabetes. Compared to non-diabetic patients, diabetes was associated with substantial undertreatment with cardioprotective medications, including antiplatelet agents, beta blockers, and statins. During a mean follow-up of 10 (SD 3.3) months, patients with both diabetes and cardiovascular disease had the worst prognosis, with the primary outcome occurring at a rate of 16.3 per 100 person-years of follow-up. Conclusions Patient registries provide a powerful tool for examining treatment patterns, risk factors, and outcomes. Patients with both cardiovascular disease and diabetes had the highest rates of adverse vascular outcomes. Possible reasons include relatively worse risk factor profiles and undertreatment with proven cardiovascular medications.