Because patients with peripheral arterial disease (PAD) may be asymptomatic or may present with atypical symptoms or findings, the true population prevalence of PAD is essentially unknown. We used four highly reliable, sophisticated noninvasive tests (segmental blood pressure, flow velocity by Doppler ultrasound, postocclusive reactive hyperemia, and pulse reappearance halftime) to assess the prevalence of large-vessel PAD and small-vessel PAD in an older (average age 66 years) defined population of 613 men and women. A total of 11. 7% of the population had large-vessel PAD on noninvasive testing, and nearly half of those with large-vessel PAD also had small-vessel PAD (5.2%). An additional 16.0% of the population had isolated small-vessel PAD. Large-vessel PAD increased dramatically with age and was slightly more common in men and in subjects with hyperlipidemia. Isolated small-vessel PAD, by contrast of PAD by the traditional methods, intermittent claudication and pulse palpation. MethodsAll 624 subjects were members of a geographically defined population initially studied under a Lipid Research Clinics (LRC) protocol.20 21 Subjects were recruited for the study with an introductory letter, followed by a telephone call to schedule an appointment. About half of the subjects (5 1.7%) were from a random sample of the LRC cohort and-the others were selected from the same earlier study for hyperlipidemia, defined as being at or above age-and sex-specific 90th percentiles for cholesterol concentration or 95th percentiles for triglyceride concentration or use of lipid-lowering medications. Subjects were from a predominantly white, upper-middle-class community in southern California, and informed consent was obtained after the procedures had been fully explained.Eleven subjects (1.8%) were excluded because of missing data or unreliable results of noninvasive testing. Two hundred seventy-five men and 338 women ranging in age from 38 to 82 years (mean 66) remained. One hundred fifty-eight subjects were 38 to 59 years old, 161 were 60 to 69 years old, and 294 were 70 to 82 years old.Criteria

In a companion article we have reported the prevalence, in an older, defined population, of traditional assessments (intermittant claudication and abnormal pulse examination) of peripheral arterial disease (PAD) as compared with the results of highly accurate noninvasive testing. In this article we report the sensitivity, specificity, and positive and negative predictive values for claudication and abnormal pulses for the diagnosis of large-vessel and small-vessel PAD as determined by noninvasive testing. Claudication and abnormal pulses were completely unrelated to isolated small-vessel PAD. In contrast, both claudication and abnormal pulses were significantly correlated with large-vessel PAD. Claudication and an abnormal femoral pulse showed a high specificity and positive predictive value but a low sensitivity for large-vessel PAD. Conversely, an abnormal dorsalis pedis pulse showed a good sensitivity but low specificity and positive predictive value. The best single discriminator was an abnormal posterior tibial pulse, which had high sensitivity, specificity, and positive predictive value. Various combinations of claudication and pulse abnormalities revealed a good sensitivity for broader criteria but at the expense of specificity, whereas stricter criteria had a good specificity and positive predictive value but a poor sensitivity. No combination was superior to an abnormal posterior tibial pulse alone. Additional analyses revealed that atypical leg pain was more common in patients with large-vessel PAD than in those without, that subjects with isolated large-vessel PAD in the posterior tibial artery did not have claudication, that claudication was rare until large-vessel PAD could be detected bilaterally by noninvasive testing, and finally that in the presence of large-vessel PAD concomitant small-vessel PAD was a marker for more severe large-vessel PAD. These results provide a useful guide to the utility and to the limitations of traditional clinical evaluation of PAD. Circulation 71, No. 3, 516-522, 1985. IN A COMPANION ARTICLE, we have outlined the prevalence of peripheral arterial disease (PAD) in a defined population as assessed first by traditional clinical evaluation (intermittent claudication and pulse palpation) and second by highly accurate, recently developed noninvasive testing procedures. This article evaluates the degree of overlap between traditional clinical evaluation and noninvasive testing results to determine the sensitivity, specificity, and predictive value of positive and negative findings of claudication and pulse palpation, both individually and in combination, for noninvasively diagnosed PAD. These results also shed light on the nature and degree of PAD sufficient to cause symptoms. MethodsAll 624 subjects were members of a geographically defined population initially studied under a Lipid Research Clinics (LRC) protocol.2' 3 Subjects were recruited for the study with an introductory letter, followed by a telephone call to schedule an appointment. About half of the subj...

The authors used noninvasive techniques, including flow velocity by Doppler ultrasound, to accurately assess and distinguish between large and small vessel peripheral arterial disease in a population study in southern California, 1978-1981. In 565 men and women aged 38-82 years, there were 69 cases of large vessel peripheral arterial disease, 19 of which were severe, and 90 cases of isolated small vessel peripheral arterial disease. In cross-sectional multivariate analysis in men, large vessel peripheral arterial disease was significantly associated with age, pack-years of cigarettes smoked, systolic blood pressure, fasting plasma glucose, and marginally with obesity. Similar analysis in women revealed significant associations only for age and systolic blood pressure, although the associations for pack-years of cigarettes, obesity, and low density lipoprotein cholesterol were suggestive. By contrast, isolated small vessel peripheral arterial disease was not significantly associated with any of the major cardiovascular disease risk factors, including two measures of carbohydrate metabolism, fasting plasma glucose and glycosylated hemoglobin. These findings, coupled with our earlier report that large vessel peripheral arterial disease but not isolated small vessel peripheral arterial disease was independently predictive of subsequent mortality, suggest that large vessel peripheral arterial disease and isolated small vessel peripheral arterial disease are epidemiologically, as well as pathophysiologically, distinct entities.

During the late 1970s, there was a dramatic reduction in postmenopausal estrogen use in the United States, which may have reflected concern over a well-publicized postmenopausal estrogen-endometrial cancer link. The authors studied 310 postmenopausal women in a defined population over the period 1974-1981 to evaluate whether hysterectomy and certain other characteristics predicted change in postmenopausal estrogen use status during this period and, as a secondary issue, whether women who subsequently began postmenopausal estrogen use had different characteristics prior to use, an important question in the evaluation of the relation of postmenopausal estrogen use to morbidity and mortality from cancer, cardiovascular disease, or other diseases in observational studies. The only strong predictor of whether postmenopausal estrogen use would be discontinued was the presence of an intact uterus. Women who discontinued postmenopausal estrogen use were also somewhat older and heavier than those who continued, but were otherwise quite similar on a wide range of variables, including risk factors for and the presence of various chronic diseases. Similarly, the absence of a uterus was the only strong predictor of the initiation of postmenopausal estrogen use. Thus, concern about a possible postmenopausal estrogen-endometrial cancer link appeared to have been the major determinant of change in postmenopausal estrogen use in this time period. In the secondary analysis, variables other than hysterectomy did not discriminate between women who initiated postmenopausal estrogen use versus those who did not report use of postmenopausal estrogens, suggesting that a broad range of other characteristics was not a priori different in these two groups.

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