Differences in Treatment Patterns and Outcomes Between Hispanics and Non-Hispanic Whites Treated for ST-Segment Elevation Myocardial Infarction

To the Editor

Ethnic disparities in contemporary ST-segment elevation myocardial infarction (STEMI) management have not been well characterized (1). The National Cardiovascular Data Registry Acute Coronary Treatment and Intervention Outcome Network–Get With The Guidelines Registry (ACTION Registry– GWTG) is the largest national database including consecutive acute coronary syndrome patients from all U.S. geographic regions and therefore provides a unique opportunity to compare contemporary treatment patterns and outcomes between Hispanic and non-Hispanic white STEMI patients.

Between January 2007 and March 2009, 46,245 STEMI patients were treated at 333 sites and included in the ACTION Registry–GWTG. Race/ethnicity was self-reported by the patient or family member, and classified by U.S. Census Bureau categories. A total of 5,633 patients who were neither Hispanic nor White, or who had missing race/ethnicity information were excluded. Patient characteristics, hospital treatment, in-hospital outcomes, and discharge therapies were compared between Hispanic and non-Hispanic white groups. Continuous variables were compared with the Wilcoxon rank sum test, and categorical variables with the Mantel-Haenszel chi-square test. Logistic generalized estimating equation modeling examined associated risk-adjusted mortality, adjusting for patient-level risk factors adapted from a validated mortality risk model and hospital characteristics (number of beds, geographic location, academic status, percutaneous coronary intervention [PCI] capability, and percent Hispanic patients treated).

Hispanics represented 4.1% (n = 1,655) of STEMI patients in ACTION Registry–GWTG. Hispanics were younger (median age: 57 vs. 62 years, p < 0.0001), more frequently had diabetes (33% vs. 21%, p < 0.0001), and had lower prevalence of prior MI (15% vs. 19%, p = 0.001) and prior revascularization procedures (18.6% vs. 23.4%, p < 0.0001) compared with non-Hispanic whites. Hispanics were significantly more likely to be uninsured (27% vs. 12%, p < 0.0001). Both ethnic groups sought care at similar types of hospitals.

Significant delays in initial triage and reperfusion were observed for Hispanic patients (Table 1). Use of acute medications (aspirin 98%, clopidogrel 87%, beta-blockers 95%, anticoagulation 89%, and glycoprotein IIb/IIIa inhibitors 70%) and primary PCI was similar between groups.

Table 1.

Initial Evaluation, Times to Intervention, In-Hospital Treatment, and Discharge Care

	Hispanics (n = 1,654)	Non-Hispanic Whites (n = 38,844)	p Value
Initial evaluation and times to intervention
Symptom onset to hospital arrival, h	2.0 (1.0–4.5)	1.6 (0.97–3.42)	<0.0001
Ambulance use	41.5%	47.0%	<0.0001
Pre-hospital ECG	32.8%	37.5%	<0.0001
Arrival to ECG, min	8 (4–15)	6 (3–12)	<0.0001
Arrival to ECG <10 min	61.2%	69.3%	<0.0001
Door to balloon, min	74 (55–94)	69 (53–87)	<0.0001
Door to balloon <90 min	69.4%	77.5%	<0.0001
In-hospital treatment during first 24 h
Diagnostic catheterization	89.1%	88.7%	0.44
Reperfusion therapy	91.5%	93.1%	0.041
Primary PCI	81.6%	80.3%	0.17
Drug-eluting stent	47.9%	49.2%	0.47
Discharge care
Smoking cessation counseling	96.2%	96.7%	0.44
Diet counseling	95.2%	94.3%	0.16
Exercise counseling	84.6%	88.1%	<0.0001
Cardiac rehabilitation referral	68.9%	82.1%	<0.0001

Values are mean (range) or %.

ECG = electrocardiogram; PCI = percutaneous coronary intervention.

Unadjusted in-hospital death (5% vs. 5.9%, p = 0.14) was similar between ethnic groups, and persisted after adjustment for patient and hospital characteristics (adjusted odds ratio: 1.07; 95% confidence interval: 0.81 to 1.43). The mean in-hospital length of stay was longer among Hispanics (4.85 ± 5.03 days vs. 4.38 ± 4.54 days, p < 0.0001).

Prescriptions of evidence-based discharge medications were similar between ethnic groups (aspirin 98%, clopidogrel 91%, beta-blockers 96%, and statins 92%) although differences in discharge care were noted (Table 1).

Despite a growing population, Hispanics remained underrepresented in nationwide registries (1). Several reasons can be postulated. Enrollment in this voluntary registry may result in underrepresentation of regions and hospitals enriched with Hispanic patients. Less likely to be insured, Hispanics may also be less likely to have a regular source of medical care (1,2). Because of the fact that a larger proportion of Hispanics in the United States are younger, there is an expected lower prevalence of CAD.

Our study found significant differences in the process of care. Times to presentation, first electrocardiogram, and reperfusion therapy were longer in Hispanic patients. The reasons for these delays cannot be elucidated from the information in the registry; however, several potential explanations could be offered. Cultural differences, lack of recognition or knowledge of the alarming symptoms, language-related barriers, insurance status, social support, and educational level, may all play a role in this delay (2– 4). DuBard et al. (3) demonstrated that the language barrier is a major factor associated with poor recognition of cardiovascular symptoms among Hispanic patients. Lambert et al. (4) demonstrated that arriving to the emergency room without the use of the ambulance system was associated with reperfusion delays and significant increases in 30-day mortality. Smolderen et al. (2) showed longer pre-hospital delays to treatment and decreased utilization of reperfusion therapy among uninsured patients.

Despite differences in clinical characteristics and delays to reperfusion, the adjusted in-hospital mortality was similar between ethnic groups. This phenomenon, labeled the “Hispanic paradox,” has also been noted in other conditions (1). In-hospital use of evidence-based and discharge therapies was remarkably similar between ethnic groups, and provide reassuring evidence of improvements instituted in the health system to eliminate racial/ethnic treatment disparities, a principal goal of Healthy People 2010 (5). However, delays to treatment and differences in post-discharge care remain evident among contemporary STEMI patients (1). The relationship between hospital care, in-hospital outcomes, as well as its long-term follow-up implications is certainly an area that requires future research efforts.

In conclusion, Hispanic patients treated for STEMI have similar clinical outcomes compared with non-Hispanic-whites. However, longer delays to STEMI recognition and reperfusion treatment, as well as less utilization of evidence-based discharge care, were observed among Hispanic patients. Quality improvement initiatives and education efforts specifically designed for the Hispanic population are warranted.