Racial/Ethnic Differences in Trust/Mistrust and Its Effect on Diabetes Outcomes
Racial/Ethnic Differences in Trust/Mistrust and Its Effect on Diabetes Outcomes
1. Determine racial/ethnic differences in trust in physicians and mistrust of the health
 care system among veterans with Type 2 Diabetes.

 2. Determine the predictive power of trust in physicians and mistrust of the health care
 system on personal health practices and health outcomes in a prospective cohort of
 veterans with Type 2 Diabetes
Background/Significance: Diabetes mellitus is a chronic and progressive disease that causes
 significant morbidity and mortality and increases health care utilization and costs in both
 Veteran Administration (VA) and non-VA settings. 1. Diabetes and its complications are more
 prevalent in minority populations. Black Americans have two-fold increased age adjusted rates
 of diabetes, are more likely to develop and experience greater disability from diabetes
 complications compared to White Americans. 1. Black Americans with diabetes have higher rates
 of retinopathy, end-stage renal disease, lower limb amputations, and overall death rates. 2.
 Therefore, diabetes is a significant public health problem and Black American patients have
 disproportionately higher morbidity and mortality than their White American counterparts.

 Several factors have been postulated to explain the disproportionately higher morbidity and
 mortality from diabetes in Black Americans and these include their mistrust of the health
 care system. 3. It is thought that distrustful patients are less likely to seek routine
 medical care, take prescribed medications consistently, adhere to treatments recommendations,
 and maintain continuity with health care providers and health care systems. 4. Recent studies
 show that Black Americans are less trusting of physicians and the health care system. 5.
 However, little is known about the association between trust and diabetes outcomes and
 whether distrust of physicians and the health care system contributes to the observed
 racial/ethnic differences in diabetes outcomes.

 Theoretical Framework: The conceptual and theoretical framework of this study is the revised
 behavioral model of health services use (Andersen 1974, 1968, 1983, 1995). The model posits
 that people's use of health services is a function of their predisposition to use services,
 factors that enable or impede use, and their need for care (Andersen 1995). Trust in
 physicians and the health system falls under health beliefs (attitudes toward health
 services), which is one of the predisposing factors that is thought to predict health
 services utilization and health outcomes. Thus, people with high levels of trust in
 physicians and the health care system are expected to have more effective access, appropriate
 health utilization, and better health outcomes. The model has been revised to include
 veteran-specific variables such as level of service entitlement, period of service, duration
 in the VA system, and disability status and to measure both health services use and health
 outcomes.

 Research Design and Methods: This is a prospective cohort study with five hypotheses
 organized under their specific aims as follows:

 Specific Aim #1: Determine racial/ethnic differences in trust in physicians and mistrust of
 the health care system among veterans with Type 2 Diabetes.

 Hypothesis #1: There is a difference in mean scores on the general trust in physician scale
 (GTIPS) between White and Black American veterans with Type 2 diabetes.

 Hypothesis #2: There is a difference in mean scores on the Health Care System Distrust Scale
 between White and Black American veterans with Type 2 diabetes.

 Specific Aim #2: Determine the predictive power of trust in physicians and mistrust of the
 health care system on personal health practices and health outcomes in a prospective cohort
 of veterans with Type 2 Diabetes

 Hypothesis #1: Controlling for predisposing, enabling, need, and veteran-specific factors,
 diabetic veterans with lower trust scores or higher mistrust scores will be less likely to
 keep office appointments, take prescribed medications, and adhere to diabetes self-management
 recommendations after 12 months of follow-up.

 Hypothesis #2: Controlling for predisposing, enabling, need, and veteran-specific factors,
 diabetic veterans with lower trust scores or higher mistrust scores will have higher mean
 hemoglobin A1C, blood pressure, and LDL cholesterol levels after 12 months of follow-up.

 Hypothesis #3: Controlling for predisposing, enabling, need, and veteran-specific factors,
 diabetic veterans with lower trust scores or higher mistrust scores will be less likely to
 accept influenza vaccination after 12 months of follow-up.

 Study site & Subjects: Patients will be recruited from the Charleston VAMC. Equal number of
 White and Black American veterans aged 18 years and older with Type 2 Diabetes will be
 recruited. Race/ethnicity will be based on self-report. The diagnosis of type 2 Diabetes as
 well as health utilization and diabetes-specific health outcomes will be obtained from the VA
 electronic medical records system (CPRS). There are approximately 6,961 patients with Type 2
 Diabetes at this site, of which 49.1% (3,417) are White Americans, 31.5% (2,189) are Black
 Americans, and 19.4% (1,355) are Hispanic or other. Approximately 97.5% are men and 90% are
 aged 50 years or older.

 Sample size calculation:

 Specific Aim #1: Sample Power V2.0 (SPSS) was used for sample size calculation based on the
 convention outlined by Cohen6. Overall experiment wise error was held to ?=0.05, and power to
 80% using medium (0.25) effect sizes. Correction for multiplicity of tests (2 tests for
 primary hypotheses) involved using ?=0.025 (0.05/2). This yielded 125 patients per group. In
 addition, the sample was inflated to account for an estimated 20% attrition at 1 year of
 follow-up (death, relocation, or loss to follow-up). No more than 150 eligible patients need
 to be enrolled per group. Thus, 300 patients (150 Whites and 150 African Americans) will be
 recruited.

 Specific Aim #2: The sample size determination for a reliable regression equation offered by
 Stevens7 is 15 subjects per predictor variable. Using this standard, a sample size of 300, as
 determined above, would allow the inclusion of 20 predictor variables. Because none of the
 hypotheses for Specific Aim 2 exceed 20 predictor variables, a sample of 300 will be
 adequate.

 Survey Instruments: The GTIPS4 is a valid and reliable 11-item measure of general trust in
 physicians and the Health Care System Distrust Scale is a valid and reliable 10-item measure
 of mistrust of the health care system. Both instruments have been validated in Black and
 White Americans.

 Statistical Analysis Plan: Descriptive statistics will be used to describe the
 characteristics of participants in the study.

 Specific Aim #1: Mean scores on the trust and mistrust scales at baseline will be compared
 between White and Black Americans with the two-sample t-test and similar comparisons will be
 made while controlling for covariates (predisposing, enabling, need, and veteran-specific
 factors) using Analysis of Covariance (ANCOVA).

 Specific Aim #2: Multiple linear regression will be used to test the effect of mean
 trust/mistrust scores on health utilization and mean hemoglobin A1C, blood pressure, and LDL
 cholesterol after 12 months of follow-up controlling for covariates. Similarly, multiple
 logistic regression will be used to test the effect of trust/mistrust on acceptance of the
 influenza vaccine controlling for covariates. STATA V8.0 will be used for data analysis and
 all tests will be two-tailed with overall p=0.05 for each hypothesis.
Inclusion Criteria:

 -  Patients for this study will be recruited from the Ralph H. Johnson VAMC in
 Charleston, South Carolina.

 -  American veterans aged 18 years and older with Type 2 Diabetes will be recruited.

 Exclusion Criteria:

 -  Children will not be included as this study pertains to type 2 diabetes, which is not
 a disease of children.

 -  Non-English speaking patients are excluded to eliminate bias in the response to
 questionnaires because these questionnaires have only been validated in English
 speaking patients.

 -  We decided to exclude cognitively impaired individuals because of the complexity of
 the survey instruments.