Stanford School of Medicine
Associate Director, Office of Health Equity and Community Engagement, Stanford Cancer Institute
Dissertation Title: "How Tribes Choose Between Tribal and Indian Health Service Management of Health Care Resources; Drug Coverage and Drug Use by Medicare Beneficiaries; Bias in Measures of Guideline Adherence"
This dissertation is composed of three separate studies. The first paper is entitled, "The Road Not Taken: How Tribes Choose Between Tribal and Indian Health Service Management of Health Care Resources." It examines trends in tribal management of health care resources since passage of the American Indian Self-Determination and Education Assistance Act of 1975 (PL 638). Administrative data were used to identify characteristics of tribes that chose to take over management of health care service units from the Indian Health Service between 1980 and 1995. An unresponsive local Indian Health Service, a large tribal bureaucracy, and greater tribal financial resources were all predictive of tribal management. In order to fulfill the promise of the 1975 legislation, Congress should address issues of inequity in Indian Health Service responsiveness and inadequate funding for health care services.
The second paper, "The Use of Prescription Drugs by Medicare Beneficiaries with Hypertension: Does Drug Coverage Matter?," explores the relationship between coverage for outpatient prescription drugs and the use of essential medications by Medicare beneficiaries with hypertension. Controlling for demographic and health status characteristics, we found a significant and positive association between drug coverage and consumption of anithypertensives. We also explored the use of a propensity score to control for selection bias due to adverse selection and eligibility rules. Given what we know of the life-saving potential of antihypertensive agents, we have a moral and ethical obligation to ensure that all persons with hypertension have coverage for these essential medications.
The final paper, "Evidence of Self-Report Bias in Assessing Adherence to Guidelines," examines trends in the use of self-report measures in research on adherence to practice guidelines and the impact of response bias on the validity of these measures. The use of self-report measures increased from 18% of studies in 1980 to 41% of studies in 1985. Further, in 87% of 37 comparisons, self-reported adherence rates exceeded the objective rates, resulting in a median over-estimation of adherence of 27% (absolute difference). Given evidence of response bias, we recommend that self-reports be used only in conjunction with objective measures in studies of guideline adherence.