NEW ORLEANS — The incidence of sudden cardiac death is markedly greater in low-income neighborhoods, according to new data from the Oregon Sudden Unexplained Death Study.
Socioeconomic status is known to be an important predictor of many aspects of health, cardiovascular and otherwise.
But the Oregon Sudden Unexplained Death Study (Ore-SUDS) is the first formal look at its impact on sudden cardiac death (SCD) on a community-wide basis, Kyndaron Reinier, Ph.D., noted at the annual meeting of the Heart Rhythm Society.
Ore-SUDS is an ongoing Centers for Disease Control and Prevention-sponsored prospective, population-based study of SCD in Portland and surrounding Multnomah County. Dr. Reinier presented data on the 714 confirmed cases in 2002–2004. The annual incidence was 54 per a population of 100,000.
Each case was matched to the appropriate county census tract, of which there are 170, each containing 3,000–4,000 people. Ore-SUDS investigators ranked the tracts in quartiles of socioeconomic status as reflected in four measures: median income, percent of the population below the official poverty level, median home value, and the percentage of residents having a bachelor's degree.
They also calculated the SCD incidence for each quartile, determining that the incidence among individuals residing in the lowest quartile for each of the four socioeconomic status indicators was 30%–80% higher than for those in the top quartile.
For example, the annual SCD incidence among residents of census tracts in the bottom quartile in terms of median home value was 62 per 100,000, compared with 36 per 100,000 in the top quartile.
This represented a 70% increase in relative risk, said Dr. Reinier of Oregon Health and Science University, Portland.
The inverse relationship observed between socioeconomic status and SCD was much stronger among individuals who experienced SCD before age 65. (See box.)
The prevalence of coronary artery disease as reflected in medical records and autopsy reports did not differ between SCD victims in the various quartiles. Neither did body mass index or rates of attempted resuscitation, said Dr. Reinier.
Median home value and the other measures of socioeconomic status used in the study are really just proxies for some as-yet unidentified factor related to poverty that raises SCD risk, she added.
KEVIN FOLEY, RESEARCH