Where You Live Matters: The Impact of Place of Residence on Severe Sepsis Incidence and Mortality

Background Medically underserved areas are composed of vulnerable populations with reduced access to ambulatory care services. Our goal was to determine the association between residence in a medically underserved area and severe sepsis incidence and mortality. Methods Using administrative data, we identified adults admitted with severe sepsis to nonfederal hospitals in South Carolina. We determined whether each resident lived in a medically underserved area or nonmedically underserved area from US Census and Department of Health and Human Services data. Age-adjusted severe sepsis incidence and mortality rates were calculated and compared between both residential classifications. Multivariate logistic regression measured the association between residence in a medically underserved area and mortality while adjusting for confounders. Results In 2010, 24,395 adults were admitted with severe sepsis and 1,446,987 (43%) adults lived in a medically underserved area. Residents of medically underserved areas were admitted more frequently with severe sepsis (8.6 vs 6.8 cases/1,000 people, P < .01) and were more likely to die (15.5 vs 11.9 deaths/10,000 people, P < .01), with increased odds of severe sepsis-related death (OR, 1.12) after adjustment for age, race, and severity of illness. ZIP code-based surrogates of socioeconomic status, including median income, proportion below poverty level, and educational attainment, however, had minimal association with sepsis mortality. Conclusions Residence in a medically underserved area is associated with higher incidence and mortality rates of severe sepsis and represents a novel method of access-to-care adjustment. Traditional access-to-care surrogates, however, are poorly associated with sepsis mortality.