People with lower incomes and education levels are more likely to die after a heart attack than more affluent, educated people, according to researchers at Mayo Clinic.
The findings are based on a study, in which researchers examined medical records of 705 patients, who were treated for heart attack between Nov. 1, 2002 and May 31, 2006.
They recorded the years of schooling completed and neighbourhood income for each participant.
Patients were divided into three income groups and three education groups. Researchers analysed survival data across these different groups.
They found that among the 155 deaths recorded during the study period, one-year survival estimates across income groups were lowest for people with the lowest income.
Seventy-five percent were survivors among people earning 28,732 dollars to 44,665 dollars; 83 percent survived among people earning 49,435 dollars to 53,561 dollars; and 86 percent survived among people earning 56,992 dollars to 74,034 dollars.
In the same way, the survival rates were lowest for participants with less education.
The study showed that 67 percent were survivors among those who had fewer than 12 years of education; 81 percent survived among people with 12 years of education; and 85 percent survived among people with greater than 12 years of education.
According to researchers, while many previous studies have sought to link socio-economic status and poor outcomes following heart attack, this study design has yielded some unique results.
"Interestingly, despite the higher-than-average socio-economic status of this population, the associations of individual education and neighbourhood income with death after heart attack were stronger than those reported in many previous studies," said Mayo Clinic cardiovascular researcher Yariv Gerber, Ph.D., the study's lead author.
"We think our approach of evaluating two different and complementary indicators of socio-economic status allowed us to capture a wider spectrum of this complex theory," Gerber added.
According to researchers, the association observed for education could be related to education's positive effect on factors that include job opportunities, income, housing, access to nutritious foods and health insurance.
"Higher levels of education also could directly affect health through greater knowledge acquired during schooling and greater empowerment and self-efficacy. As recently reported, education is strongly associated with health literacy, which in turn affects one's ability to obtain, process, and understand basic health information and services needed to make appropriate health decisions," Gerber said.
Researchers also point out that more specific mechanisms linking low socio-economic status to survival following heart attack could also be related to the greater difficulty that poorer individuals with lower education levels have in attending cardiac rehabilitation programs and adhering to medications and lifestyle recommendations.
The study is published in the June issue of Mayo Clinic Proceedings.