Background: Intermittent claudication is associated with a poor prognosis, but less is known of the risks associated with asymptomatic peripheral arterial disease. The aims of this study were to determine the incidence and natural history of claudication, and the incidence of cardiovascular events in symptomatic and asymptomatic peripheral arterial disease.
Methods: In 1988, 1592 subjects aged 55-74 years were selected randomly from the age-sex register of 10 general practices in Edinburgh, Scotland. The presence of peripheral arterial disease was determined by the World Health Organization questionnaire on intermittent claudication, the ankle brachial pressure index and a reactive hyperaemia test. This cohort was followed prospectively over 5 years for subsequent cardiovascular events and death.
Results: One hundred and sixteen new cases of claudication were identified (incidence density 15.5 per 1000 person-years). Of those with claudication at baseline, 28.8% and still had pain after 5 years, 8.2% underwent vascular surgery or amputation, and 1.4% developed leg ulceration. Claudicants had a significantly increased risk of developing angina compared with normals (RR: 2.31, 95% CI: 1.04-5.10), and asymptomatic subjects had a slightly increased risk of myocardial infarction and stroke. Deaths from cardiovascular disease were more likely in both claudicants (RR: 2.67, 95% CI: 1.34-5.29) and subjects with major (RR: 2.08, 95% CI: 1.13-3.83) or minor asymptomatic disease (RR: 1.74, 95% CI: 1.09-2.76). Subjects with major asymptomatic disease also had an increased risk of non-cardiovascular death (RR: 2.19, 95% CI: 1.33-3.59), and therefore had the highest overall risk of death (RR: 2.44, 95% CI: 1.59-3.74).
Conclusions: Subjects with asymptomatic peripheral arterial disease appear to have the same increased risk of cardiovascular events and death found in claudicants.