Validity of telephone interview data for vascular disease risk factors in a racially mixed urban community: The Northern Manhattan Stroke Study

The aims of our study were to assess the validity and reliability of a tele phone survey instrument designed to measure vascular disease risk factors a nd to assess whether these measurements were influenced by age, gender, rac e/ethnicity, or other sociodemographic variables. Subjects were sampled and interviewed using random digit dialing methodology from the multiethnic co mmunity of northern Manhattan. For the validity study, 261 consecutive subj ects were clinically assessed in-person within 60 days of the telephone int erview. A retest reliability study of the telephone interview was conducted in 92 randomly selected subjects within 30 days of the initial interview. The telephone interview instrument had a sensitivity of more than 55% and a specificity of 74% or greater for various vascular disease risk factors. S ensitivity, specificity, and positive predictive value did not vary signifi cantly or systematically among whites, blacks, and Hispanics, but subjects with access to health care were more likely to provide valid data. The reli ability substudy indicated a good reliability for the telephone interview. These results support the validity of telephone interviews for estimating t he prevalence of vascular risk factors in urban populations.