Abstract 973: Contemporary Burden of Sudden Cardiac Death in San Francisco County, 2007: Substantial Differences in Rates by Race and Gender
Introduction: Sudden cardiac death (SCD) is a major public health problem in the US. The true burden of SCD remains unknown; variable definitions and inconsistent ascertainment methods in previous studies have resulted in widely divergent estimates of SCD incidence, from 184,000 to nearly 450,000 deaths per year. We examined the contemporary burden of SCD in a diverse community, San Francisco County (SF). We hypothesized that:
the standard World Health Organization (WHO) criteria for SCD are highly inaccurate for true sudden arrhythmic death (SAD), and
rates of SAD in SF differ substantially by race and gender.
Methods: A panel of 3 physicians reviewed all deaths reported to the SF Medical Examiner (ME) in 2007 for presentations fitting WHO criteria for SCD–within 1 h of symptom onset (witnessed) or within 24 h of having been observed alive and symptom free (unwitnessed)– blinded to subsequent ME investigation and evaluation. From this group, we performed a comprehensive review of circumstances of death, medical records, and autopsy data to determine the final cause of death, categorized as SAD or non-arrhythmic SD (e.g., CHF deaths, drug overdose, PE, occult cancer).
Results: We identified 262 WHO SCDs (rate 34.6/100,000 persons; mean age 61.3 years, 69.9% male) accounting for 4.3% of overall mortality. ASDs accounted for 147 of 262 WHO SCDs (PPV for WHO criteria 56.1%, rate 19.4/100,000). ASD rate was 2.3-fold higher among men (26.8/100,000 vs. women 11.8/100,000; p=0.002). ASD rates were highest among Black males (56.3/100,000) and lowest among Hispanic females (5.9/100,000). Asians (16.5/100,000) and Hispanics (11.2/100,000) both had lower ASD rates compared to Whites (20.2/100,000), p=0.054 and p<0.0005 respectively.
Conclusions: The widely accepted WHO criteria for SCD have a low PPV for SAD, the most relevant phenotype from a public health perspective. This finding highlights the need for refinement of criteria for the definition of SCD. We found a substantially higher SAD rate among Blacks and lower rates among Asians and Hispanics as compared to Whites. These differences likely reflect the changing epidemiology of SCD in a contemporary, diverse population. The much higher rate of SAD among Black men warrants further investigation.