Objective: Public policy that decreases the finding for social services may combine with the ascendancy of corporate managed care to increase the health care deficit. Assessing the health impact of these policy changes on various populations is a fundamental challenge for health services research. Disadvantaged populations, such as the homeless, are likely to be affected disproportionately. Research quality data on the physical health of such populations are difficult and expensive to obtain. In particular, physical examination data have not been available and self-reports are insufficient. Our objective: to develop and utilize a structured physical exam system enabling lay survey researchers to report reliably physical findings related to six tracer conditions in a disadvantaged population.
Study setting: A field survey of homeless adults in Los Angeles County, California. Respondents were 363 homeless adults representing a subsample of a probability sample of the county's homeless adult population.
Study design: We integrated existing measures with expert clinical opinion and original means of data collection into a structured physical exam enabling lay interviewers to identify the prevalence of vision problems, significant skin disorders, peripheral vascular disease of the lower extremities, selected podiatric disorders, hypertension, and tuberculosis in a sample of homeless adults.
Principal measures: We describe lay interviewer performance in terms of mastery of the necessary material based on written and practical exams and in terms of the number of respondents successfully followed. We base our description of the instrument on the time necessary to complete it, and on the proportion of each component successfully completed during the field survey, as well as on interrater reliability. We report the prevalence of the various clinical conditions according to self-report and according to the structured limited physical exam, as well as the marginal proportion of respondents who were identified by the physical exam and not by self-report.
Principal findings: Interviewers performed the exam successfully under field conditions. Respondent acceptance of the instrument was high. Interrater agreement was 100 percent regarding the need for referral on the basis of blood pressure and vision. Kappa statistics for skin, foot, and edema findings were .67,.71, and .81, respectively. Adjusted for sampling weights, 60 percent of this population required referral for at least one of the specified conditions. For those portions of the survey for which both self-report and physical exam data were available, lay interviewers made significant percentages of referrals on the basis of physical findings alone.
Conclusions: High blood pressure, poor vision, peripheral vascular diseases of the feet and legs, and significant skin conditions are prevalent among the homeless in Los Angeles County. Without physical exam data, estimates of the prevalence of these conditions will be incorrect. Researchers can use laypersons to collect reliable and valid physical exam data on disadvantaged populations. This represents a new tool for assessing and monitoring the health of these populations.