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J Gen Intern Med. May 2008; 23(5): 692–698.
Published online Feb 21, 2008. doi:  10.1007/s11606-008-0547-7
PMCID: PMC2324164
Racial Differences in Blood Pressure Control: Potential Explanatory Factors
Hayden B. Bosworth, PhD,corresponding author1,2,3 Benjamin Powers, MD,1,2 Janet M. Grubber, MSPH,1,2 Carolyn T. Thorpe, PhD,1 Maren K. Olsen, PhD,1,4 Melinda Orr, MEd,1 and Eugene Z. Oddone, MHS1,2
1Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center (152), Durham, NC USA
2Department of Medicine, Division of General Internal Medicine, Duke University, Durham, NC USA
3Department of Psychiatry and Behavioral Sciences and Center for Aging and Human Development, Duke University, Durham, NC USA
4Department of Biostatistics and Bioinformatics, Duke University, Durham, NC USA
Hayden B. Bosworth, Phone: +1-919-2866936, Fax: +1-919-4165836, hayden.bosworth/at/duke.edu.
corresponding authorCorresponding author.
Received August 20, 2007; Revised December 28, 2007; Accepted January 26, 2008.
Objective
The objective of the study was to identify potential explanatory factors for racial differences in blood pressure (BP) control.
Design
The design of the study was a cross-sectional study
Patients/Participants
The study included 608 patients with hypertension who were either African American (50%) or white (50%) and who received primary care in Durham, NC.
Measurements and Main Results
Baseline data were obtained from the Take Control of Your Blood pressure study and included clinical, demographic, and psychosocial variables potentially related to clinic BP measures. African Americans were more likely than whites to have inadequate baseline clinic BP control as defined as greater than or equal to 140/90 mmHg (49% versus 34%; unadjusted odds ratio [OR] 1.8; 95% confidence interval [CI] 1.3–2.5). Among factors that may explain this disparity, being older, reporting hypertension medication nonadherence, reporting a hypertension diagnosis for more than 5 years, reporting high levels of stress, being worried about hypertension, and reporting an increased number of medication side effects were related to inadequate BP control. In adjusted analyses, African Americans continue to have poor BP control relative to whites; the magnitude of the association was reduced (OR = 1.5; 95% CI 1.0–2.1). Medication nonadherence, worries about hypertension, and older age (>70) continued to be related to poor BP control.
Conclusions
In this sample of hypertensive patients, there were a number of factors associated with poor BP control that partially explained the observed racial disparity in hypertension control including age, medication nonadherence, and worry about BP. Medication nonadherence is of particular interest because it is a potentially modifiable factor that might be used to reduce the racial disparity in BP control.
KEY WORDS: racial disparity, hypertension, adherence, psychosocial
Hypertension affects 65 million U.S. adults, and another 45 million are prehypertensive.1 It has been estimated that among adults more than 50 years of age, the lifetime risk of developing hypertension approaches 90%.2 Hypertension is the major modifiable risk factor for stroke and is 1 of the major risk factors for coronary heart disease, congestive heart failure, and renal disease.35 Because hypertension is 1 of the major contributing factors to a host of cardiovascular diseases, even small racial/ethnic differences in its optimum management have large implications for outcomes.
African Americans suffer a disproportionately large burden of cardiovascular morbidity and mortality in the United States compared to white patients; half of the cardiovascular mortality disparity between African Americans and whites is directly attributable to hypertension.6 Although blood pressure (BP) treatment and control rates for both whites and African Americans have increased significantly from 1988–1994 to 1999–2002, African Americans continue to lag behind whites in achieving BP goals.7 Furthermore, the disparity in BP control among treated cases has grown, with an increased BP control of 24% among whites and only an increased BP control of 18% among African Americans during this time period.
The explanation for the persisting racial differences in hypertension control and in cardiovascular and renal outcomes is not fully known but may include biological, cultural, social, and health care provider and system factors.8 Whereas historically, there have been significant racial disparities in the accessibility of health care, improved access to care and medications does not necessarily ensure better hypertension control for African Americans.9,10 These observations suggest that in addition to equal access, patient, provider, and health care system characteristics contribute to racial disparities.11 Accurate identification of these variables is essential in allocating resources to support effective solutions. We examined various demographic, clinical, behavioral, and psychosocial factors that may explain these racial differences in BP control among a sample of individuals with hypertension recruited from 2 large primary care clinics.
We used baseline data from the Take Control of Your Blood pressure trial, a 2 by 2 factorial design testing 2 interventions (tailored behavioral intervention and BP self-monitoring). Potentially eligible individuals were selected through a medical electronic database from a pool of 7,646 unique patients who were diagnosed with hypertension (International Classification of Diseases-9 codes 401.9, 401.0, and 401.1), seen in 1 of the 2 community primary care clinics for at least 1 year before enrollment, and were currently using a medication for hypertension (angiotensin-converting enzyme inhibitors, beta blockers, calcium channel blockers, diuretics, alpha1 blockers, and central alpha2 agonists) at baseline.12
The trial occurred in 2 Duke University Health System primary care clinics: (1) Duke General Internal Medicine, where most patients have private insurance or Medicare and are cared for by General Internists, and (2) Duke Outpatient Clinic, a hospital-based primary care clinic committed to underserved patients with limited financial resources and where primary care providers are predominantly residents in the Duke Department of Medicine residency training program.
Research assistants mailed letters that explained the study from patients’ doctors to 1,501 potentially eligible patients with upcoming appointments. Six hundred and thirty-six patients were enrolled, 630 refused, and 235 were excluded for the following reasons: not prescribed or using a hypertension medication; spouse participating in the study; did not live in a surrounding 8 county catchment area; receiving kidney dialysis; received an organ transplant; planning a pregnancy; arm measurements outside the BP monitor parameters (>43 cm); hospitalized for stroke, myocardial infarction, or coronary artery revascularization or received a diagnosis of metastatic cancer in the prior 3 months; diagnosed with dementia; residing in a nursing home or receiving home health care; or severely impaired hearing or speech. An additional 28 individuals were not included in the current analyses because their race was not African American or white or because they were missing clinic BP readings, resulting in a final sample size of 608 subjects. Participants were reimbursed $25 each for the study visit. The Duke Institutional Review Board approved this study. Data used in the current study were collected before implementation of the intervention.
Outcome—Blood Pressure Control
Clinic BP readings taken on the day the patient completed the baseline interview were obtained from patients’ medical records. Registered nurses used standard automated BP devices to systematically obtain BP values before the physician visit and entered them into a computerized medical record system. Lack of BP control was defined as BP greater than or equal to 140/90 mmHg.
Potential Explanatory Variables
Whereas there are a number of potential variables that may explain disparities in BP control, we used the revised health decision model8 to guide the selection of the various measures/items we assessed in our analyses. The measures and items we chose to assess, along with their definitions and categorizations, are listed below.
Demographic
We evaluated sex using male as the referent category. Financial situation was assessed by asking patients to report whether they had enough money after paying bills for special things; enough to pay the bills, but not purchase extra things; enough money to pay bills by cutting back on things; or difficulty paying bills no matter what is done.13 The latter 2 categories were categorized as inadequate income. Age was categorized into the following groups: 25–50, 51–60, 61–70, and greater than 70.
Psychosocial
The Rapid Estimate of Adult Literacy in Medicine (REALM)14 was used to measure health-related literacy. The REALM has high criterion-related validity as compared to longer literacy measures.15,16 Health literacy was evaluated as a dichotomous variable with low literacy defined as REALM score, 0–60 (less than 9th grade level) and adequate literacy defined as REALM score 61–66 (greater than or equal to 9th grade level). This operationalization was based on prior convention and is consistent with findings correlating low literacy and mortality using this categorization.17 Medical regimen-specific recall was measured by asking subjects to read and repeat aloud a sentence that represented typical instructions that a provider would give to patients to help reduce hypertension. (i.e., take your medication once in the morning and once at night). The number of correctly remembered phrases (out of 10) were recorded and summed to create a recall variable. Seven items were used to assess barriers to medication treatment (e.g., side effects, confusion about how many pills to take, keeping track of pills). These items are a subset of the 56-item barriers to adherence checklist.18 Responses were recoded and ranged from 1 (definitely true) to 4 (definitely false), where lower scores indicated more barriers. The internal consistency for this scale was acceptable (Cronbach’s alpha = 0.75). A summary score was created by summing across the individual scores such that the higher the score, the fewer the barriers.
Self-reported medication adherence was assessed using a 4-item measure based on Morisky’s scale19 (i.e., I sometimes forget to take my BP medicine; I am sometimes careless about taking my BP medicine; When I feel better, I sometimes stop taking my BP medicine; If I feel worse when I take the BP medicine, sometimes I stop taking it). Response options ranged from strongly agree (1) to strongly disagree (4). The internal consistency of these variables was acceptable (Cronbach’s alpha = 0.85). A summary binary variable was created by coding those who responded strongly agree, agree, don’t know, or refuse to any of the 4 questions as nonadherent; otherwise, patients were coded as adherent. The adherence measure did not specify a time period over which participants were supposed to report adherence; therefore, the measure assessed global, rather than specific, adherence.20 Seven items from the modified hypertension beliefs questionnaire were used to assess knowledge and perceived risks.21 Each of the items was scored with a 1 for a correct response or a 0 for an incorrect response. Using a prior scoring algorithm,20,22,23 all 7 items were summed to calculate an overall hypertension knowledge score and then categorized into high (7) versus low (0–6) knowledge. Perceived stress was assessed by asking participants to report how often in the past month they felt stressed (never, almost never, sometimes, fairly often, very often). Fairly often and very often were categorized as “Often feel stressed.” Patients’ views of their providers’ communication behaviors were assessed using the revised 3-item Participatory Decision Making survey.24 Patients rated how likely, on the scale of 1 (never/unlikely) to 10 (always/very likely) their doctor was to: (1) involve them in treatment decisions, (2) ask them to take some responsibility in their care, and (3) give them a sense of control over their medical care. The ratings for these 3 questions were summed to create a participatory decision-making score ranging from 3 to 30 when all questions were completed (Cronbach’s alpha = 0.74). Worry about hypertension was assessed by asking individuals how worried they were about their high BP, using a 10-point scale (1 = definitely not worried to 10 = extremely worried). A single question assessed whether individuals perceived that health professionals controlled one’s health. Responses of strongly agree and agree were categorized as “lack personal control of health,” and disagree and strongly disagree were categorized as “have personal control of health.” The amount of emotional social support patients receive was also assessed using a validated item.25 The respondents were asked “Do you have someone you feel close to, someone you can trust and confide in?” Responses were yes or no.
Clinical
Subjects were classified according to whether they had a home BP monitor (yes/no). Time since hypertension diagnosis was examined as 0–5 years versus greater than 5 years. Individuals were asked whether a parent or sibling was diagnosed with hypertension (yes/no). Patients answered yes or no to whether they experienced a list of 15 standard side effects that are associated with antihypertensive medication use, including increased urination, lethargy, and dry mouth among others. The total number of “yes” responses was summed to create a side effects score.
Health behaviors were assessed utilizing single-item questions asking participants if they exercise or smoke cigarettes.26 Specifically, participants were asked how much time per week they spent on aerobic or body movement activities such as brisk walking, jogging, or running that elevated their heart rate for 20 minutes and made them sweat/perspire. Subjects who reported that they never did this during a week were classified as having no weekly exercise. The question assessing smoking was dichotomous and asked the participants whether or not they currently smoked. Diabetes (yes/no) was self-reported by patients in response to the question, “Has a doctor ever told you that you had diabetes, high blood sugar, or sugar in your urine?” Subjects who reported having a blood relative (parent, brother, or sister) with high BP were classified as having a family history of hypertension.
To assess potential explanations for racial disparities in BP control, we first verified that a racial disparity existed in our sample by using unadjusted logistic regression to calculate odds ratios (ORs) for the association between lack of BP control and race (African American versus white [referent]). We then used logistic regression analyses to calculate unadjusted ORs and 95% confidence intervals (CIs) for the association between lack of BP control and each candidate’s explanatory variable. Candidate explanatory variables that changed the OR for the association between lack of BP control and race by greater than or equal to 10%27,28 were included in the final multivariable model. We tested for interactions between race and each of the candidate explanatory variables from the multivariable model, but none were significant. SAS version 9.1 (Cary, NC, USA) was used for all analyses.
Patient Sample
Patients’ mean age was 61 years (range 25–92 years), 66% were female, and 50% were African American (see Table 1). About half the sample (50%) was married, 36% had a high school education or less, 18% reported having inadequate incomes, and 61% were employed. In terms of clinical information, 66% of the sample reported having been diagnosed with high BP for 5 or more years, and 77% had at least 1 family member with hypertension. Based upon the REALM literacy measure, 27% of the sample had an 8th grade or less literacy level. Twenty-three percent of the sample did not report any exercise lasting 20 or more minutes during the last week, and 16% were currently using tobacco products.
Table 1
Table 1
Patient Sample Characteristics, Overall and Stratified by Race
As shown in Table 1, 45% of African-American and 26% of white patients were diabetic. Baseline clinic systolic BP was 139.5 mmHg (SD = 21.9) for African Americans and 131.1 mmHg (SD = 17.4) for whites. The diastolic BP was 80.1 (SD = 11.7) for African Americans and 75.5 (SD = 10.0) for whites. Fifty-one percent of African Americans and 66% of whites had their BP under control at baseline (<140/90 mmHg).
Associations Between Race, Potential Explanatory Variables, and Lack of Blood Pressure Control
African Americans were significantly more likely to have poor BP control relative to whites (49% versus 34%; unadjusted OR = 1.8; 95% CI, 1.3–2.5). Potential explanatory variables were relatively consistently related to BP control in unadjusted and adjusted models with the exception that low health literacy and poor hypertension knowledge were only significant in unadjusted models (Table 2). After adjusting for race, a number of potential explanatory variables were significantly associated with BP control for the full sample: increased age greater than 70 (OR = 2.1; 95% CI 1.2–3.4), medication nonadherence (OR = 1.6; 95% CI 1.1–2.2), experience stress fairly or very often (OR = 1.4; 95% CI 1.0–1.9), increased worry about hypertension (OR = 1.1; CI 95% 1.0–1.2), greater than 5 years since hypertension diagnosis (OR = 1.5; 95% CI 1.0–2.1), and increased number of medication side effects (OR = 1.1; 95% CI 1.0–1.1; see Table 2).
Table 2
Table 2
Unadjusted and Race-adjusted Associations Between Lack of Blood Pressure Control and Demographic, Psychosocial, and Clinical Factors
Final Multivariable Model
The variables that modified the association between race and BP control by greater than 10% included age, worry about hypertension, and medication nonadherence. There were no significant interactions detected between race and any of these 3 explanatory variables. The ORs for the associations between lack of BP control and these variables were: age (>70 versus 25–50 year olds; OR = 2.5; 95% CI 1.5–4.3), worry about hypertension (for each, 1 unit increase on a 10-point response scale, OR = 1.1; CI 95% 1.0–1.2), and medication nonadherence (OR = 1.6; 95% CI 1.1–2.3). In this final model, after accounting for these explanatory variables, African Americans remained significantly more likely to have inadequate BP control relative to whites; however, the magnitude of this association was diminished from OR = 1.8 (95% CI 1.3–2.5) to OR = 1.5 (95% CI 95% 1.0–2.2).
In this diverse sample of primary care patients with hypertension, we observed a significant difference in odds of BP control between white and African-American patients. After accounting for psychosocial, clinical, and demographic factors, including medication nonadherence, age, and worry about hypertension, we could explain some but not all of the racial differences in BP control. The explanation for the persistent racial differences in hypertension control is not fully known, but the current study provides some explanations for these differences. Specifically, worry about hypertension and hypertension medication nonadherence partly explained racial disparities in BP control. An accurate assessment of variables contributing to health disparities is essential for allocating resources to support effective solutions.
Understanding factors that explain racial disparities in hypertension control is important given that the decline in cardiovascular deaths in the United States has not been uniformly distributed across racial groups.29,30. In our study, we found that African Americans were less likely to have BP control than whites. It is interesting to note that our inability to account for racial differences in BP control is consistent with prior studies3133 including 1 we conducted in a VA system, a relatively equal access system.22 Thus, despite adjusting for a number of potential explanatory factors, African Americans continued to have significantly higher odds of having poor BP control relative to whites. Despite examining hypertension control in 2 different samples (e.g., VA setting with equal access and university primary care setting), unadjusted ORs for the association between the African-American race and lack of BP control were similar (OR = 1.70; OR = 1.80, respectively), and whereas there were more factors that explained these differences in the current study, the overall levels of disparities in adjusted models remained relatively consistent (OR = 1.59, OR = 1.50, respectively).
We observed that African Americans were more worried about their BP than whites and that an increase in worry about one’s BP was associated with worse BP control. Worry and higher perceived vulnerability for a disease have has been associated with an increase in preventive health behavior,34 making these findings somewhat surprising. It is possible that the poor BP control precedes and directly causes the increased worry; however, it is difficult to determine in our cross-sectional design. It is also possible that despite potentially accurately worrying more about their hypertension, African Americans may have fewer resources than whites to reduce their BP, thus providing a possible explanation for our counterintuitive finding of a positive relationship between worry and poor BP control.
Medication adherence in patients with treated hypertension is estimated at between 50% and 70%.3537 These rates are comparable to what was observed in the current study (64% of the current sample reported being adherent with their medication). Fifty percent of African Americans reported they were adherent, whereas 79% whites reported being adherent. These racial differences in medication adherence are similar to prior studies.22,3845 Consequently, it has been suggested that patients and their physicians be targeted for interventions to identify and remediate adherence barriers as well as other factors leading to the disparity in health outcomes.46,47 Whereas this racial difference in adherence is striking, it did not completely explain differences in BP control.
Other studies have found an association between age and BP control, although there are inconsistencies between studies. In patients more than 60 years old, a decrease in arterial compliance results in systolic BP rising, whereas diastolic BP may fall.48 This widened pulse pressure potentially makes hypertension more difficult to control in the elderly because of the risk of harm from excessive lowering of diastolic BP.49 The 1999–2004 National Health and Nutrition Examination Survey analyses of BP control suggests that among the greater than or equal to 60 age group, awareness, treatment, and control rates of hypertension have all increased significantly over the last 4–5 years and were better than in younger adults.50 In a large comparative study, investigators showed comparable screening rates across age groups (>90%) but did not report actual differences in BP control.51 However, a national population sample that included adequate numbers of older adults found a decrease in BP control with increasing age (e.g., 75% among 45–64 and 61% among those 75–84).52 We observed a higher percent of hypertension control in younger people. Clinically, with increasing comorbidities and other clinical manifestations of hypertension in older adults, the control tends to be hard to achieve.
This study has several potential limitations. The study population is a university-affiliated general Internal Medicine clinic and a community outpatient clinic, and the treatment of hypertension may not be representative of those experienced by the general population. However, the sample represented a diverse group of hypertensive patients in terms of race, literacy levels, and socioeconomic status. Related, there were some population differences between the 2 clinics sites, but available measures that may account for these differences (e.g., insurance status, literacy levels) were examined. Second, although we examined a number of factors that could potentially explain racial disparities in BP control, other relevant factors may not have been identified. Another limitation of this study was the inability to assess physician-related variables, including practice patterns, physician race, and the role that physician/patient racial discordance may have on patient outcomes.53 However, it is important to note that participatory decision making, an indication of the patient–physician interaction, was not associated with racial disparities in BP control. There were also participation differences in terms of race and age (e.g., 55% of the total clinic population versus 48% of the total enrolled sample were African American; 57% of the clinic population were older than 66 years of age compared to 63% in the total enrolled sample from which the current study population was drawn). Finally, we did not examine insurance status because it was correlated with age. Nevertheless, only 20 (3%) of the sample reported that they were uninsured.
The results of this study have both clinical and research implications. Our results suggest that before implementing more intensive hypertensive treatments to improve BP control among African Americans, more attention to hypertension medication adherence may be required. Poor adherence may be influenced by barriers to care like cost and access to care. Thus, the improvement of hypertension treatment and control requires a better understanding of differences in the prevalence of hypertension and determinants of hypertension control among minority groups in the United States. Strategies that address poor BP control may contribute greatly to reducing the cardiovascular health disparities in the United States.
Acknowledgment
This research is supported by a grant from the National Heart, Lung, and Blood Institute (R01 HL070713), a grant from the Pfizer Health Literacy Communication Initiative Foundation, and an Established-Investigator award from the American Heart Association to the first author. Dr. Powers is supported through the Mentored Clinical Research Scholar Program through Duke and the NIH (KL2 RR024127). Dr. Thorpe was supported by an Office of Academic Affairs VA-funded postdoctoral fellowship.
Conflict of Interest None disclosed.
1. Chobanian AV , Bakris GL, Black H, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 Report. JAMA. 2003;289(19):2560–71. [PubMed]
2. Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for developing hypertension in middle-aged women and men: the Framingham Heart Study. JAMA. 2002;287(8):1003–10. [PubMed]
3. Stamler J, Stamler, Neaton J. Blood pressure, systolic and diastolic, and cardiovascular risks: U.S. population data. Arch Intern Med. 1993;153:598–615. [PubMed]
4. Perry H, Roccella EJ. Conference report on stroke mortality in the southeastern United States. Hypertens. 1998;31:1206–15.
5. Kannel W. Blood pressure as a cardiovascular risk factor, prevention and treatment. JAMA. 1996;275:1571–6. [PubMed]
6. Wong MD, Shapiro MF, Boscardin WJ, Ettner SL. Contribution of major diseases to disparities in mortality. N Engl J Med. 2002;347(20):1585–92. [PubMed]
7. Hertz RP, Unger AN, Cornell JA, Saunders E. Racial disparities in hypertension prevalence, awareness, and management. Arch Intern Med. 2005;165(18):2098–104. [PubMed]
8. Bosworth HB, Oddone EZ. A model of psychosocial and cultural antecedents of blood pressure control. J Natl Med Assoc. 2002;94(4):236–48. [PMC free article] [PubMed]
9. Kotchen JM, Shakoor-Abdullah B, Walker WE, Chelius TH, Hoffmann RG, Kotchen TA. Hypertension control and access to medical care in the inner city. Am J Public Health. 1998;881(11):696–9. [PubMed]
10. Berlowitz DR, Ash AS, Hickey EC, et al. Inadequate management of blood pressure in a hypertensive population. N Engl J Med. 1998;339(27):1957–63. [PubMed]
11. Weinick RM, Zuvekas SH, Cohen JW. Racial and ethnic differences in access to and use of health care services, 1977 to 1996. Med Care Res Rev. 2000;57(Suppl 1):36–54. [PubMed]
12. Bosworth HB, Olsen MK, Dudley T, et al. The Take Control of Your Blood pressure (TCYB) study: study design and methodology. Contemp Clin Trials. 2007;28(1):33–47. [PubMed]
13. Bosworth HB, Bastian LA, Kuchibhatla MN, et al. Depressive symptoms, menopausal status, and climacteric symptoms in women at midlife. Psychosom Med. 2001;63(4):603–8. [PubMed]
14. Parker R, Baker DW, Williams MV, Nurss JR. The test of functional health literacy in adults: a new instrument for measuring patients’ literacy skills. J Gen Intern Med. 1995;10:537–41. [PubMed]
15. Davis T, Long SW, Jackson RH, et al. Rapid estimate of adult literacy in medicine: a shortened screening instrument. Family Med. 1993;25:391–5.
16. Baker DW, Williams MV, Parker RM, Gazmararian JA, Nurss J. Development of a brief test to measure functional health literacy. Patient Educ Couns. 1999;38(1):33–42. [PubMed]
17. Dewalt DA, Berkman ND, Sheridan S, Lohr KN, Pignone MP. Literacy and health outcomes: a systematic review of the literature. J Gen Intern Med. 2004;19(12):1228–39. [PMC free article] [PubMed]
18. Catz SL, Kelly JA, Bogart LM, Benotsch EG, McAuliffe TL. Patterns, correlates, and barriers to medication adherence among persons prescribed new treatments for HIV disease. Health Psychol. 2000;19(2):124–33. [PubMed]
19. Morisky DE, Green LW, Levine DM. Concurrent and predictive validity of a self-reported measure of medication adherence. Med Care. 1986;24(1):67–74. [PubMed]
20. Lowry KP, Dudley TK, Oddone EZ, Bosworth HB. Intentional and unintentional nonadherence to antihypertensive medication. Ann Pharmacother. 2005;39(7–8):1198–203. [PubMed]
21. Jette A, Cummings KM, Brock BM, Phelps MC, Naessens J. The structure and reliability of health belief indices. Health Serv Res. 1981;16:81–98. [PMC free article] [PubMed]
22. Bosworth HB, Dudley T, Olsen MK, et al. Racial differences in blood pressure control: potential explanatory factors. Am J Med. 2006;119(1):70 e9–15. [PubMed]
23. Hong TB, Oddone EZ, Dudley TK, Bosworth HB. Subjective and objective evaluations of health among middle-aged and older veterans with hypertension. J Aging Health. 2005;17(5):592–608. [PubMed]
24. Kaplan SH, Gandek B, Greenfield S, Rogers W, Ware JE. Patient and visit characteristics related to physicians’ participatory decision-making style. Results from the Medical Outcomes Study. Med Care. 1995;33(12):1176–87. [PubMed]
25. Williams RB, Barefoot JC, Califf RM, et al. Prognostic importance of social and economic resources among medically treated patients with angiographically documented coronary artery disease. JAMA. 1992;267:520–4. [PubMed]
26. Bosworth HB, Hoff J, Box T et-al. Patient factors related to poor blood pressure control. Poster presented at the 19th Annual Health Service Research and Development Meetings. Washington, DC; 2001.
27. Rothman K, Greenland S. Modern Epidemiology. 2nd ed. Philadelphia, PA: Lippincott-Raven; 1998.
28. Schildkraut J, Demark-Wahnefried W, Wenham RM, et al. IGF1(CA)19 Repeat and IGFBP3 -202 A/C Genotypes and the Risk of Prostate Cancer in Black and White Men. Cancer Epidemiol Biomarkers Prev. 2005;14(2):403–8. [PubMed]
29. Cooper R, Sempos C, Hsieh SC, Kovar MG. Slowdown of the decline of stroke mortality in the United States, 1978–1986. Stroke. 1990;21:1274–9. [PubMed]
30. Sempos C, Cooper R, Kovar MG, McMillen M. Divergence of the recent trends in coronary mortality for the four major race–sex groups in the United States. Am J Public Health. 1988;78(11):1422–7. [PubMed]
31. Kramer H, Han C, Post W, et al. Racial/ethnic differences in hypertension and hypertension treatment and control in the multi-ethnic study of atherosclerosis (MESA). Am J Hypertens. 2004;17(10):963–70. [PubMed]
32. Hajjar I, Kotchen TA. Trends in prevalence, awareness, treatment, and control of hypertension in the United States, 1988–2000. JAMA. 2003;290(2):199–206. [PubMed]
33. Svetkey LP, George LK, Tyroler HA, Timmons PZ, Burchett BM, Blazer DG. Effects of gender and ethnic group on blood pressure control in the elderly. Am J Hypertens. 1996;9(6):529–35. [PubMed]
34. McCaul KD, Schroeder DM, Reid PA. Breast cancer worry and screening: some prospective data. Health Psychol. 1996;15(6):430–3. [PubMed]
35. Psaty B, Koepsell TD, Yanez D, et al. Temporal patterns of antihypertensive medication use among adults, 1989 through 1992. JAMA. 1995;273:1436–8. [PubMed]
36. Caro JJ, Speckman JL, Salas M, Raggio G, Jackson JD. Effect of initial drug choice on persistence with antihypertensive therapy: the importance of actual practice data. CMAJ. 1999;160(1):41–6. [PMC free article] [PubMed]
37. Bosworth HB, Olsen MK, Gentry P, et al. Nurse administered telephone intervention for blood pressure control: a patient-tailored multifactorial intervention. Patient Educ Couns. 2005;57(1):5–14. [PubMed]
38. Charles H, Good CB, Hanusa BH, Chang CC, Whittle J. Racial differences in adherence to cardiac medications. J Natl Med Assoc. 2003;95(1):17–27. [PMC free article] [PubMed]
39. Black D, Brand RJ, Greenlick M, Hughes G, Smith J. For the SHEP Pilot Research Group. Compliance to treatment for hypertension in elderly patients: The SHEP pilot study. J Gerontol. 1987;42:552–7. [PubMed]
40. Monane M, Bohn RL, Gurwitz JH, Glynn RJ, Levin R, Avorn J. Compliance with antihypertensive therapy among elderly Medicaid enrollees: the roles of age, gender, and race. Am J Pub Health. 1996;86(12):1805–8. [PubMed]
41. Psaty BM, Manolio TA, Smith NL, et al. Time trends in high blood pressure control and the use of antihypertensive medications in older adults: the cardiovascular health study. Arch Intern Med. 2002;162(20):2325–32. [PubMed]
42. Hyman DJ, Pavlik VN. Characteristics of patients with uncontrolled hypertension in the United States. N Engl J Med. 2001;345(7):479–86. [PubMed]
43. Burt V, Whelton P, Roccella EJ, et al. Prevalence of hypertension in the US adult population: results from the third National Health and Nutrition Examination Survey. 1988–1991. Hypertens. 1995;25:305–13.
44. Schectman JM, Bovbjerg VE, Voss JD. Predictors of medication-refill adherence in an indigent rural population. Med Care. 2002;12:1294–300. [PubMed]
45. Monane M, Bohn RL, Gurwitz JH, Glynn RJ, Levin R, Avorn J. Compliance with antihypertensive therapy among elderly Medicaid enrollees: the roles of age, gender, and race. Am J Pub Health. 1996;86(12):1805–8. [PubMed]
46. Brach C, Fraser I. Can cultural competency reduce racial and ethnic health disparities? A review and conceptual model. Med Care Res Rev. 2000;57(Suppl 1):181–217. [PubMed]
47. Fiscella K, Franks P, Gold MR, Clancy CM. Inequality in quality: addressing socioeconomic, racial, and ethnic disparities in health care. JAMA. 2000;283(19):2579–84. [PubMed]
48. Franklin SS, Gustin WT, Wong ND, et al. Hemodynamic patterns of age-related changes in blood pressure. The Framingham Heart Study. Circulation. 1997;96(1):308–15. [PubMed]
49. Messerli FH, Mancia G, Conti CR, et al. Dogma disputed: can aggressively lowering blood pressure in hypertensive patients with coronary artery disease be dangerous? Ann Intern Med. 2006;144(12):884–93. [PubMed]
50. Ong KL, Cheung BM, Man YB, Lau CP, Lam KS. Prevalence, awareness, treatment, and control of hypertension among United States adults 1999–2004. Hypertens. 2007;49(1):69–75.
51. Holmes JS, Arispe IE, Moy E. Heart disease and prevention: race and age differences in heart disease prevention, treatment, and mortality. Med Care. 2005;43(3 Suppl):I33–41. [PubMed]
52. Howard G, Prineas R, Moy C, et al. Racial and geographic differences in awareness, treatment, and control of hypertension: the REasons for Geographic And Racial Differences in Stroke study. Stroke. 2006;37(5):1171–8. [PubMed]
53. Cho AH, Voils CI, Yancy WS Jr, Oddone EZ, Bosworth HB. Does participatory decision making improve hypertension self-care behaviors and outcomes? J Clin Hypertens (Greenwich). 2007;9(5):330–6. [PubMed]
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