Intermittent claudication in 8343 men and 21-year specific mortality follow-up.

OBJECTIVE

As Western populations live longer, peripheral vascular disease will become a greater individual and public health problem. Therefore, the long-term natural history of intermittent claudication (IC) needs further delineation. The study objective was to describe the 21-year mortality and relative risk for cause-specific mortality for subjects with incident IC.

METHODS

The subjects were 8343 Israeli male governmental employees aged 40-65 years who were free of coronary heart disease and symptomatic peripheral vascular disease in 1963. These men were followed for 21 years to measure differences in mortality between those who did and did not develop incident IC. Incident IC was diagnosed in 1965 and 1968 by the London School of Hygiene IC Questionnaire. All other cardiovascular disease risk factors were measured by standardized and validated procedures. Cause-specific mortality through 1986 was determined through death certificates from the Israeli Mortality Register.

RESULTS

A total of 360 men with IC and 7983 symptom-free men were followed for survival from 1965 to 1986; 159 men with IC (44%) and 2330 symptom-free men (29%) died. For total mortality, the Kaplan-Meier 21-year survival probabilities were 56% for IC and 71% for symptom-free men (P < 0.0001 for the entire 21-year survival difference between the two groups). For coronary heart disease (CHD), stroke, and other causes of death, the survival probabilities for men with IC and symptom-free men were, respectively: 85% vs. 90%, 89% vs. 97%, and 79% vs. 83% (P = 0.0004; P < 0.0001; and P = 0.007, respectively, for the entire 21-year survival difference between the two groups). Cox's proportional hazards model was used to control confounding from incident myocardial infarction and angina through 1968, as well as for demographic, physiologic, psychosocial, and other cardiovascular disease risk factors. The 21-year adjusted all-cause mortality relative risk for IC was 1.50 (95% confidence interval (CI), 1.28-1.77). For stroke deaths the relative risk was 2.76 (95% CI, 1.89-4.02). For stroke mortality, IC was the third strongest predictor of death after elevated systolic blood pressure and increasing age. Incident IC had a relative risk of CHD deaths of 1.31, but it was not statistically significant (P = 0.08; 95% CI, 0.97-1.77). IC was not statistically significantly related to other causes of death (P = 0.10) after adjustment for covariates.

CONCLUSIONS

IC is strongly predictive of long-term cerebrovascular disease mortality among men. Incident IC is a stronger indicator of cerebrovascular than of CHD death.