OBJECTIVES

To examine the association between social vulnerability index (SVI) and social deprivation index (SDI) with critical illness-related mortality in the United States and to guide future research and interventions aimed at reducing disparities in outcomes in patients with critical illness.

DESIGN

A cross-sectional study using county-level data.

SETTING

United States with data sourced from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research and the American Community Survey.

PATIENTS

County-level populations of all ages across the United States from 2015 to 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Age-adjusted mortality rates for four categories of critical illnesses (respiratory, cardiac, neurologic, and renal/gastrointestinal) were analyzed against the county-level SVI and SDI. We assessed critical illness-related mortality associated with SVI and SDI through negative binomial regression models. Mortality rates per 100,000 were highest for cardiac (212.4; 95% CI, 212.2-212.6), followed by respiratory (116.8; 95% CI, 116.7-117.0), neurologic (30.8; 95% CI, 30.8-30.9), and renal/gastrointestinal illnesses (25.2; 95% CI, 25.1-25.3). Mortality was greater among adults 65 years old and older, males, Black or African American individuals, and those living in rural areas. Higher SVI and SDI were associated with increased mortality, with the strongest correlation found for cardiac critical illnesses, showing rate ratios of 1.52 (95% CI, 1.48-1.57) for SDI and 1.43 (95% CI, 1.39-1.47) for SVI. Specific diagnoses with the highest incidence rate ratios included sepsis (1.63 [95% CI, 1.58-1.69] for SVI and 1.75 [95% CI, 1.70-1.80] for SDI), cardiac arrest (1.92 [95% CI, 1.80-2.04] for SVI and 1.98 [95% CI, 1.86-2.10] for SDI), anoxic brain damage (1.62 [95% CI, 1.45-1.81] for SVI and 1.60 [95% CI, 1.45-1.76] for SDI), and acute hepatic failure (1.51 [95% CI, 0.92-2.46] for SVI and 1.49 [95% CI, 1.08-2.05] for SDI). The SDI demonstrated a stronger correlation with mortality compared with the SVI, with socioeconomic status, poverty, education, and unemployment being the most impactful indicators.

CONCLUSIONS

Critical illness mortality is significantly associated with indicators of socioeconomic disadvantage. The SDI appears to be a more effective tool than the SVI for guiding resource allocation. Targeted interventions to address social determinants of health, including poverty, education, and unemployment, are essential to reduce disparities and improve outcomes in patients with critical illness. Public health strategies should focus on addressing these social determinants and enhancing support for vulnerable populations and areas.