"Patients living in neighborhoods with a high percentage of residents living below the poverty line had a death rate after heart attack 30 percent higher than those in the wealthiest neighborhoods," said lead author Cathryn Tonne, M.P.H., a doctoral candidate in environmental epidemiology at Harvard's School of Public Health in Boston, Mass.
The poverty line is an income threshold based on family size, age of children and income. In 1999, the poverty threshold for a family of four was $17,029 per year.
Researchers used data from the ongoing Worcester Heart Attack Study, a community-wide study of trends in the incidence and survival after heart attack among residents from Worcester, Mass.
The study includes 2,539 confirmed cases of heart attack collected in 1995, 1997 and 1999. About 58 percent of the patients were male and the average age was 69. About 74 percent were still alive at follow-up on Dec. 31, 2001.
Researchers divided income levels into five groups. The death rate after heart attack was higher for the 20 percent of patients living in the poorest neighborhoods.
The analysis adjusted for demographic characteristics, hospital discharge and other conditions such as hypertension, diabetes, a history of chest pain, heart failure and stroke.
The lack of local health clinics and low-cost healthful foods, and inadequate public space for physical activity may be some factors involved in the higher risk of death after heart attack among those living in poverty, Tonne said.
"The precise pathways by which poverty at the neighborhood level affects survival have not yet been identified, but residents of deprived neighborhoods may be of poorer overall health and experience more psychosocial factors like stress, social isolation and depression.
"The relationship between poor survival after heart attack and neighborhood poverty may also be due in part to exposure to traffic-related pollutants, housing conditions and other aspects of the physical environment," she said.
The findings of the study show that even in a relatively small geographical urban area there can be a wide variation in heart attack survival, which appears to be associated with poverty. "A greater understanding of the pathways by which poverty affects survival after a heart attack may help us design more focused programs to counteract poverty's effects.
"Our results suggest that steps need to be taken to prevent excess death after heart attack at the neighborhood level in addition to those taken at the individual level," Tonne added.
Co-authors are Joel Schwartz, Murray Mittleman, Steve Melly, Helen Suh and Robert Goldberg.
Note: This release contains updated information from the abstract.