On June 25, 2024, the AHA Journals will be launching a new website design. During the launch process, there may be intermittent outages, and some features (alert sign-ups, article/issue purchases, account customizations/activations, and comment submissions) may be unavailable. This message will be removed when the launch process is complete. Thank you for your patience and we hope that you enjoy the new site!

Skip main navigation

Does Socioeconomic Status or Acculturation Modify the Association Between Ethnicity and Hypertension Treatment Before Stroke?

Originally publishedhttps://doi.org/10.1161/STROKEAHA.113.003051Stroke. 2013;44:3243–3245

Abstract

Background and Purpose—

Socioeconomic status and acculturation may modify the association between ethnicity and hypertension treatment before stroke. We assessed prestroke treatment of hypertension by ethnicity, education (proxy for socioeconomic status), and English proficiency (EP; proxy for acculturation) in a population-based stroke surveillance project.

Methods—

Among 763 patients with first-ever stroke aged ≥45 years in the Brain Attack Surveillance in Corpus Christi project from 2000 to 2006, we examined self-reported hypertension treatment at the time of the stroke by ethnicity (Mexican American [MA] versus non–Hispanic white [NHW]) in the overall sample, within education strata (<high school, high school, >high school), and after dichotomizing MAs by self-reported EP (limited versus proficient). Logistic regression adjusted associations for age, sex, education, diabetes mellitus, coronary artery disease, hypercholesterolemia, and health insurance.

Results—

NHWs and MAs reported similar hypertension treatment (84% versus 86%; P=0.53). Hypertension treatment was 84% for NHWs and 90% for MAs (P=0.18) in <high school stratum, 87% for NHWs and 75% for MAs (P=0.07) in high school stratum, and 81% for NHWs and 78% for MAs (P=0.73) in >high school stratum (ethnicity-by-education interaction, P=0.09). Hypertension treatment was 83% for NHWs, 87% for MAs with EP (PvsNHWs=0.35), and 90% for MAs with limited EP (PvsNHWs=0.13; ethnicity-by-EP interaction, P=0.22). Hypertension treatment was lower in uninsured patients (adjusted odds ratio, 0.13; 95% confidence interval, 0.03-0.60) or those with no physician visit ≤6 months (adjusted odds ratio, 0.09; 95% confidence interval, 0.03-0.24).

Conclusions—

We found no evidence that socioeconomic status or acculturation modifies the association between ethnicity and hypertension treatment before stroke.

Introduction

Ethnic disparities in the treatment of stroke risk factors may be difficult to detect13 and may only become evident when examining those with low socioeconomic status (SES) or low levels of acculturation.4 Mexican Americans (MAs) comprise 66% of all the US Hispanics and are more likely to have low SES or less acculturation.4 It is unknown whether low SES or less acculturation exacerbates MA-white differences in hypertension treatment before stroke.

We examined prestroke treatment of hypertension stratified by ethnicity, education (a valid marker of SES),5 and English proficiency (EP; a valid proxy for acculturation)6 in a population-based, biethnic stroke surveillance project.

Methods

Study Population

Stroke cases presenting between January 2000 and June 2006 were ascertained in Nueces County, TX, in the Brain Attack Surveillance in Corpus Christi project.7 Through active and passive surveillance, Brain Attack Surveillance in Corpus Christi ascertains all cases of acute cerebrovascular disease presenting to the emergency department or directly admitted to any of the 7 hospitals in Nueces County. During the study period, there was an out-of-hospital surveillance program.8 Out-of-hospital events accounted for a small percentage of acute strokes and were similar by ethnicity.3 Trained abstractors verify stroke diagnoses on the basis of rigorous criteria. Neurologists validate stroke cases using source documentation and international clinical criteria.9 At the time of their stroke hospitalization, patients or proxies for patients unable to participate completed an in-person, structured interview. Bilingual abstractors conducted the interview in English or Spanish per patient preferences. Interview participation was similar by ethnicity.7 Patients with their first Brain Attack Surveillance in Corpus Christi stroke (ischemic or hemorrhagic) were included. This project was approved by the University of Michigan and both Corpus Christi Health Systems’ Institutional Review Boards. Informed consent was obtained from all subjects.

Variables

Patients reported prestroke hypertension (physician diagnosis of high blood pressure ever) and its treatment (use of antihypertensive medication) at the time of the index stroke.

All covariates, including race-ethnicity (non–Hispanic white [NHW], MA), were self-reported except insurance status (medical record) and selected using the Andersen Behavioral Model framework.10 EP was speaking English only or bilingual (more accultured). Limited EP was speaking Spanish only (less accultured). Months from last physician visit to stroke (0–6, 6–12, 12–24, >24, and never) were recorded.

Of 1111 stroke cases identified, we excluded 328 with previous stroke/transient ischemic attack, 89 with other race-ethnicity, and 26 with no information on the outcome, leaving 763 cases in the study.

Statistical Analysis

We evaluated correlates of ethnicity (NHWs=referent) and hypertension treatment status using χ2 test or ANOVA. We used multivariable logistic regression models to examine the association between ethnicity and hypertension treatment before and after adjusting for covariates: (1) overall and within education strata (<high school, high school, ≥high school) and (2) after stratifying MAs by EP. We also compared hypertension treatment by ethnicity among those with diabetes mellitus.11

Income was significantly correlated with education (coefficient 0.54; P<0.001) so we included education alone and did sensitivity analyses adjusting for income.4 We examined interaction terms (ethnicity-by-education and ethnicity-by-EP) in the adjusted models.

Results

Hypertension treatment was similar in MAs and NHWs overall (86% versus 84%; P=0.53) and in those with diabetes mellitus (91% versus 89%; P=0.70). Online-only Data Supplement presents patient characteristics by ethnicity and hypertension treatment status.

Hypertension treatment was 84% for NHWs and 90% for MAs (P=0.18) in <high school stratum, 87% for NHWs and 75% for MAs (P=0.07) in high school stratum, and 81% for NHWs and 78% for MAs (P=0.73) in >high school stratum (ethnicity-by-education interaction, P=0.09). Hypertension treatment was 83% for NHWs, 87% for MAs with EP (PvsNHWs=0.35), and 90% for MAs with limited EP (PvsNHWs=0.13; ethnicity-by-EP interaction, P=0.22).

MAs had similar likelihood of hypertension treatment before stroke overall, within education strata, and after dichotomizing MAs by EP (Table; online-only Data Supplement). Hypertension treatment was lower in uninsured patients (adjusted odds ratio, 0.13; 95% confidence interval, 0.03–0.60) or those with no physician visit ≤6 months (adjusted odds ratio, 0.09; 95% confidence interval, 0.03–0.24). There were no ethnic differences in treatment in analyses that used medical record diagnosis of hypertension or that included income (online-only Data Supplement).

Table. Odds Ratios (95% Confidence Intervals) for Hypertension Treatment, Unadjusted and Adjusted: BASIC, 2000 to 2006

UnadjustedPartially Adjusted: Includes Sociodemographics, Comorbidity, and Health InsuranceFully Adjusted: Includes Healthcare Use*
Overall sample
 n520416289
 Mexican American1.17 (0.72–1.88)0.93 (0.49–1.78)1.33 (0.60–2.97)
c-statistic0.520.700.78
Less than high school education
 n245191141
 Mexican American1.76 (0.77–4.06)1.85 (0.70–4.90)2.98 (0.85–10.46)
c-statistic0.560.740.83
High school education
 n14911881
 Mexican American0.46 (0.20–1.08)0.45 (0.15–1.42)1.24 (0.26–5.94)
c-statistic0.590.640.77
More than high school education
 n12610767
 Mexican American0.83 (0.30–2.34)0.82 (0.18–3.85)0.71 (0.06–8.72)
c-statistic0.520.850.92

Partially adjusted models included age, sex, education, coronary artery disease, diabetes mellitus, hypercholesterolemia, and no health insurance. Fully adjusted models also included no primary care physician and last physician visit. BASIC indicates Brain Attack Surveillance in Corpus Christi.

*Available from January 2000 to 2004 only.

Discussion

We found no evidence that SES or acculturation modifies the association between ethnicity and hypertension treatment before stroke.

Several factors potentially explain our findings. Most MAs in our study were born in the United States and insured (93%). Health insurance accounts for the largest proportion of the Hispanic-white disparity in access to physician care.12 Health insurance and access to care differences may be greater in communities with more MA immigrants. Alternatively, we may have been unable to detect small ethnic differences in prestroke treatment because of sample size (n=520). On the basis of a post hoc analysis, we had 80% power (α=0.05) to detect an absolute hypertension treatment rate for MAs that was either 10% lower or 8% higher than that of NHWs (84%). Finally, ethnic differences in treatment of vascular risk factors at the population-level may vary by geographic region and may even be absent in some communities or subpopulations.13

Our study has limitations. We lacked information on control or duration of hypertension. Hispanics have worse hypertension control than whites, and this gap persisted between 1999 and 2006.14 Despite similar treatment rates, MAs may have worse prestroke hypertension control than NHWs. Moreover, our study does not preclude that ethnic differences in hypertension prevalence, treatment, or control contribute to MAs’ higher stroke incidence.3

Neither SES nor acculturation amplified ethnic differences in hypertension treatment. There was a tendency for MAs and NHWs with higher SES to have lower hypertension treatment rates before stroke, which is counterintuitive to expected trends.

Footnotes

The online-only Data Supplement is available with this article at http://stroke.ahajournals.org/lookup/suppl/doi:10.1161/STROKEAHA.113.003051/-/DC1.

Correspondence to Deborah A. Levine, MD, MPH, University of Michigan, NCRC Bldg 16 Rm 430W, 2800 Plymouth Rd, Ann Arbor, MI 48109-2800. E-mail

References

  • 1. Lisabeth LD, Smith MA, Sánchez BN, Brown DL. Ethnic disparities in stroke and hypertension among women: the BASIC project.Am J Hypertens. 2008; 21:778–783.CrossrefMedlineGoogle Scholar
  • 2. Smith MA, Risser JM, Lisabeth LD, Moyé LA, Morgenstern LB. Access to care, acculturation, and risk factors for stroke in Mexican Americans: the Brain Attack Surveillance in Corpus Christi (BASIC) project.Stroke. 2003; 34:2671–2675.LinkGoogle Scholar
  • 3. Morgenstern LB, Smith MA, Lisabeth LD, Risser JM, Uchino K, Garcia N, et al. Excess stroke in Mexican Americans compared with non-Hispanic Whites: the Brain Attack Surveillance in Corpus Christi Project.Am J Epidemiol. 2004; 160:376–383.CrossrefMedlineGoogle Scholar
  • 4. Levine DA, Allison JJ, Cherrington A, Richman J, Scarinci IC, Houston TK. Disparities in self-monitoring of blood glucose among low-income ethnic minority populations with diabetes, United States.Ethn Dis. 2009; 19:97–103.MedlineGoogle Scholar
  • 5. Winkleby MA, Jatulis DE, Frank E, Fortmann SP. Socioeconomic status and health: how education, income, and occupation contribute to risk factors for cardiovascular disease.Am J Public Health. 1992; 82:816–820.CrossrefMedlineGoogle Scholar
  • 6. Coronado GD, Thompson B, McLerran D, Schwartz SM, Koepsell TD. A short acculturation scale for Mexican-American populations.Ethn Dis. 2005; 15:53–62.MedlineGoogle Scholar
  • 7. Smith MA, Risser JM, Moyé LA, Garcia N, Akiwumi O, Uchino K, et al. Designing multi-ethnic stroke studies: the Brain Attack Surveillance in Corpus Christi (BASIC) project.Ethn Dis. 2004; 14:520–526.MedlineGoogle Scholar
  • 8. Morgenstern LB, Smith MA, Sánchez BN, Brown DL, Zahuranec DB, Garcia N, et al. Persistent ischemic stroke disparities despite declining incidence in Mexican Americans.Ann Neurol. August 13, 2013. doi:10.1002/ana.23972.CrossrefGoogle Scholar
  • 9. Asplund K, Tuomilehto J, Stegmayr B, Wester PO, Tunstall-Pedoe H. Diagnostic criteria and quality control of the registration of stroke events in the MONICA project.Acta Med Scand Suppl. 1988; 728:26–39.CrossrefMedlineGoogle Scholar
  • 10. Gelberg L, Andersen RM, Leake BD. The Behavioral Model for Vulnerable Populations: application to medical care use and outcomes for homeless people.Health Serv Res. 2000; 34:1273–1302.MedlineGoogle Scholar
  • 11. Chen G, McAlister FA, Walker RL, Hemmelgarn BR, Campbell NR. Cardiovascular outcomes in Framingham participants with diabetes: the importance of blood pressure.Hypertension. 2011; 57:891–897.LinkGoogle Scholar
  • 12. Mahmoudi E, Jensen GA. Diverging racial and ethnic disparities in access to physician care: comparing 2000 and 2007.Med Care. 2012; 50:327–334.CrossrefMedlineGoogle Scholar
  • 13. Bonds DE, Zaccaro DJ, Karter AJ, Selby JV, Saad M, Goff DC. Ethnic and racial differences in diabetes care: The Insulin Resistance Atherosclerosis Study.Diabetes Care. 2003; 26:1040–1046.CrossrefMedlineGoogle Scholar
  • 14. McWilliams JM, Meara E, Zaslavsky AM, Ayanian JZ. Differences in control of cardiovascular disease and diabetes by race, ethnicity, and education: U.S. trends from 1999 to 2006 and effects of medicare coverage.Ann Intern Med. 2009; 150:505–515.CrossrefMedlineGoogle Scholar

eLetters(0)

eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.

Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.