In the US, over the past 30 years, advances in cardiovascular care have resulted in a dramatic decline in mortality and morbidity associated with ST elevation myocardial infarction (STEMI) and non-STEMI.1,2 The overall incidence of coronary heart disease (CHD) has decreased over the last four decades.3
There are various reports about disparities in healthcare and the higher mortality among African Americans in CHD.3-5 There are few reports looking at racial disparities in the treatment of STEMI. We present our community-based experience demonstrating the disparities among African Americans and Caucasians in the treatment of STEMI.
The study was designed to test the hypothesis that there is a disparity in the treatment of STEMI among African Americans and Caucasians.
Methods and Design
A retrospective chart review on two STEMI population groups was performed - October 1995 to July 1997 (first) and October 2005 to July 2007 (second). Each of the two groups comprised patients with first event of STEMI in an 18-month timeframe at our community teaching hospital, St. Joseph Mercy Oakland, Pontiac, Michigan, US. The institutional Review Board approved this retrospective review protocol. Data collection included patient demographics, insurance status, co-morbidities, hospital length of stay (LOS) and their clinical outcome with complications if any.
Based on the risk for CHD at different age for men and women, and recommendations for treatment for dyslipidaemia from the Adult Treatment Panel (ATP) III report,6 young population in our study was defined as: males <45 years of age and females <55 years of age. In the second group, population was characterised as obese if their body mass index (BMI) was greater than or equal to 30 kilograms/ square metres (kg/m2). Tobacco use was defined as any patient who had secondary diagnoses of history of tobacco use and/or tobacco use disorder.
Racial disparities between African Americans and Caucasians were measured using their hospital mortality and LOS in the two population groups and re-intervention rate in the second group. Mortality was defined as any STEMI patient who was brought to the hospital and who died during the hospital stay either with or without invasive treatment. In the second group, re-intervention rate was calculated by review of follow-up heart catheterisation reports, if performed. In this group, all patient charts were retrieved for a minimum follow-up period of one year (until July 2008) in order to determine rate of re-intervention procedures. The other details relevant to the methods and statistical tests used can be found in our previously published report from this investigation.7
In the first group 1995-1997 (1997 group) a total of 455 subjects were included, with males comprising 64 % of the group (289 of 455). In the second group 2005-2007 (2007 group) there was a total of 206 patients, with males comprising 65 % of the group (134 of 206). The basic characteristics of the two groups are shown in Table 1. In both of our study groups there was no significant difference between African Americans and Caucasians in terms of age, prevalence of risk factors like hypertension, diabetes mellitus, dyslipidaemia and history of tobacco use. The mean age of women compared with men for first event of STEMI was 7-9 years older. As shown in Table 1 this difference was statistically significant. The prevalence of patients uninsured increased from 1.3 % in the 1997 to 4.3 % in 2007 (p=0.02). In the 2007 group, compared with Caucasians and African Americans, Hispanics were more likely to be uninsured - two of 36 young adults versus nine of 170 non-young adults were uninsured (p=1.0). In the 1997 group, three of 59 young adults versus three of 396 non-young adults were uninsured (p=0.03).
In the 2007 group, hospital mortality rate in all patients brought to the emergency room for STEMI was 12.6 % (26 of 206) - women 16.6 % (12 of 72) versus men 10.4 % (14 of 134). Hospital mortality for African Americans: one of 22 versus Caucasians: 21 of 170, 95 % confidence interval (CI) -0.178 to 0.022, with p=0.48. Multivariate analysis using binary logistic regression was used and only age was found to be a significant predictor of death (see Table 2).
In the 1997 group, the hospital mortality rate was 9.45 % (43 of 455) - women 12.65 % (21 of 166) versus men 7.61 % (22 of 289). Hospital mortality for African Americans (four of 41) versus Caucasians (39 of 402), 95 % CI -0.095 to 0.096, with p=1.0.
Length of Stay
As shown in Table 1, the mean LOS decreased from 6.67 days in 1997 to 4.46 days in 2007. In 2007 the mean LOS for African Americans was 5.7 days versus 4.1 days for Caucasians (p=0.09). Among the race, in 1997 the mean LOS for African Americans was 7.3 days versus 6.6 days for Caucasians (p=0.42).
In the 2007 group, a total of 164 percutaneous coronary interventions (PCIs) were performed for 206 patients. The remaining patients either refused invasive treatment or were not candidates for PCI. The average follow-up period was 20.5 months (range 12-32 months). During followup a total of 40 patients needed re-intervention. Re-intervention rate in African Americans being 13.6 % (three of 22) versus 21.2 % (36 of 170) in Caucasians, 95 % CI -0.231 to 0.081, with p=0.57. The re-intervention and mortality rate among the two races is shown in Figure 1.
In the US, cardiovascular disease (CVD) mortality and incidence has decreased gradually from the 1960s onwards, though the decline has slowed down.3 In our 2007 group, the rate of patients dead was higher than in the 1997 group, which is probably due to more effective current emergency medical services and due to non-exclusion of patients presenting with cardiogenic shock and cardiopulmonary resuscitation. Risk in women lags about 5-15 years behind that of men. The average age of a person having a first coronary event is 64.5 for men and 70.3 for women.8 In our study, women were seven years older than men in the 1997 group and nine years older than men in the 2007 group (see Table 1). According to the 2011 update on heart disease and stroke statistics, the number of STEMIs are decreasing,9 but the exact incidence in young is not known. In our study, obesity and family history of CHD were major risk factors for STEMI in the young.7
According to the findings of the National Conference on Cardiovascular Disease Prevention there has been a decrease in the difference in mortality rates between African Americans and the Caucasian population.3 There are other reports to suggest that the gap in CVD mortality between the various ethnic groups, poor and undereducated versus the wealthy and well-educated, has not lessened and may be widening.10 The last Cardiovascular Science and Health Care Disparities Minority Health Summit5 emphasised that racial/ethnic disparities in CVD exist and are indeed complex and multifactorial, and they occur at all levels of the medical care system. The report also mentioned that the largest difference is due to a higher mortality rate among minorities.
Although among CHD there are various reports that disparities in patient care exist,11 in our STEMI populations there was no disparity among the African American and Caucasian races in terms of mortality, length of hospital stay and cardiac re-interventions (see Table 1 and Figure 1). Our results regarding no racial disparity in the management of STEMI are in concordance with other authors.12 In the author's opinion, no racial disparity in the study is due to the systems of care in management of STEMI and to strict adherence to these treatment guidelines and protocol.
This was a retrospective review of patients with STEMI, with a relatively small number of patients studied.
In the management of STEMI there was no evidence of disparity between African Americans and Caucasians in terms of length of hospital stay, hospital mortality and re-intervention rates. Larger studies are needed to confirm these findings in the treatment of STEMI, which are in contrast to various reports of the existence of racial disparity in CVD treatment.