Abstract 11280: Effect of Homelessness on Incidence of Autopsy-Defined Causes of Presumed Sudden Cardiac Death: Insights from the San Francisco Postmortem Systematic Investigation of Sudden Cardiac Death (POST SCD) Study

Abstract

Introduction: Prior studies report higher cardiovascular mortality in persons experiencing homelessness (PEH), but presume cardiac cause of death (COD) from EMS records or death certificates. The effect of homelessness on autopsy-defined SCD is unknown. In this prospective postmortem study of all SCDs in San Francisco (SF) County, we hypothesized a greater incidence of presumed SCD in PEH, but more non-cardiac COD on autopsy. Methods: Between 2/2011 - 3/2014, all incident World Health Organization-defined (presumed) SCDs ages 18-90 were autopsied via active surveillance of out of hospital deaths in the POST SCD Study. A multidisciplinary committee adjudicated COD. Autopsy-defined SCDs had no extra-cardiac COD (e.g., overdose, pulmonary embolism, stroke). Homeless status was determined from medical records; rates of presumed and autopsy-defined SCD were compared to those for housed individuals. The countywide homeless population was determined from the 2013 SF Homeless Count and Survey. Results: We identified 525 presumed SCDs over 37 months: 36 (7%) were PEH and 489 (93%) were housed. Presumed SCDs in PEH were younger than housed subjects (56.5 ± 9.9 v. 63.2 ± 14.6 years), more often male (97% v. 67%), less likely to be Asian (0% v. 22%) or have dyslipidemia (3% v. 32%), but more likely to have alcohol (58% v. 21%) and substance use disorder (44% v. 13%, p<0.01 for all). The presence of psychiatric disorders was similar between groups. Among presumed SCDs, PEH had a lower proportion of autopsy-defined SCDs than housed individuals (9/36 [25%] v. 306/489 [63%]), with more non-cardiac COD including aspiration, aortic dissection, occult overdose, and infection (p<0.05 for all). Observed incidence rates for presumed SCD were 181.4 v. 22.7 per 100,000 person-years (IRR 8.01, p<0.01) in PEH v. housed individuals, and 45.4 v. 14.2 per 100,000 person-years (IRR 3.20, p<0.01) for autopsy-defined SCD. Conclusion: In this 3-year comprehensive postmortem study of all incident SCDs in a diverse urban setting, homelessness was associated with >3-fold higher risk of autopsy-confirmed SCD and 8-fold higher risk of sudden mortality overall. Only one-fourth of presumed SCDs in PEH were autopsy-confirmed SCDs, while one-third of non-cardiac causes were due to occult drug overdose.