Intermittent claudication: From its risk factors to its long-term prognosis in men. The Quebec Cardiovascular Study.

Background: The natural history of intermittent claudication, from its risk factors to its cardiovascular prognosis, has been reported in few prospective studies.

Objective: To assess incident intermittent claudication, as well as its risk factors and long-term prognosis in men.

Methods: A random sample of 4376 men 35 to 64 years of age from Quebec City (Quebec), who were free of cardiovascular disease (CVD), was evaluated in 1974 for CVD risk factors and followed until 1998. To assess the prognosis, the event rates between 1985 and 1998 were computed among men with incident claudication without other CVD, incident survivors of a first myocardial infarction (MI) without other CVD and men free of CVD between 1974 and 1985.

Results: From 1974 to 1998, 300 men developed intermittent claudication. Tobacco consumption, high systolic blood pressure and diabetes at least doubled the adjusted RR (aRR) of intermittent claudication. In 1985, there were 80 claudicants, 2868 men free of CVD and 68 survivors of a first MI. During the 13-year follow-up, a new CVD occurred in 48.8% of the claudicants, in 18.9% of men without CVD (aRR 2.08; 95% CI 1.48 to 2.90) and in 45.6% of MI survivors (aRR compared with claudicants 1.12; 95% CI 0.69 to 1.79). There was also no significant difference between claudicants and MI survivors for fatal CVD, nonfatal CVD and total mortality.

Conclusions: Men with intermittent claudication are at high risk for CVD that may be equivalent to men with previous MI.