The course of vascular risk factors and the occurrence of vascular events in patients with symptomatic peripheral arterial disease

Abstract

Background: Previous studies have documented an undertreatment of vascular risk factors, and patients with symptomatic peripheral arterial disease (PAD) are at increased risk of recurrent vascular events. We examined which baseline variables are related to future vascular events, investigated the course of vascular risk factors, and compared the number of vascular risk factors at baseline and at follow-up to determine whether risk factor management could be further improved. Methods: This study involved 461 patients with Fontaine classification II to IV who were enrolled in the SMART study (Second Manifestations of ARTerial disease) from September 1996 to December 2000. Patients underwent a standardized screening program for risk factors and were invited for a follow-up measurement during September 2003 to March 2005, after a mean follow-up of 5.5 years (SD, 1.3 years). In the interim period between baseline and follow-up measurement, patients received usual care. During follow-up, vascular events (mortality, ischemic stroke, and myocardial infarction) and PAD-related events (vascular surgery, interventions, and amputations) were documented in detail. Results: In 2739 person-years of follow-up, 91 vascular events occurred, resulting in a 29.1% (95% confidence interval [CI], 22.8%-35.4%) cumulative incidence proportion of recurrent vascular events. Older age, increased homocysteine levels, impaired renal function, and a history of coronary heart disease at baseline were related to an increased risk of new vascular events. Of the 461 patients, 108 patients died, 20 patients were lost to follow-up, and 333 patients were eligible for follow-up measurement, in which 221 (66%) patients wished to participate. In 8 of the 221 patients, a nonfatal vascular event occurred during follow-up. The prevalence of hypertension increased from 51% to 70% (95% CI, 10%-28%), the prevalence of obesity increased from 54% to 67% (95% CI, 3%-21%), and the prevalence of diabetes mellitus increased from 8% to 16% (95% CI, 2%-14%). At follow-up, fewer patients were current smokers (59% to 37%; 95% CI, -13% to -31%), and fewer patients had increased lipid levels (96% to 73%; 95% CI, -29% to -16%). Medication use increased in all drug categories during follow-up. Conclusions: Age, increased homocysteine levels, impaired renal function, and a history of coronary heart disease were independent risk factors for vascular events in patients with symptomatic PAD. The prevalence of most risk factors, except for smoking and hyperlipidemia, increased over a 5.5-year period even though medication use increased over the same period. © 2007 The Society for Vascular Surgery.