Socioeconomic Disparities and the Role of Comorbidity in Hospital Mortality: A Dutch Nationwide Critical Care Cohort Study.

OBJECTIVES

Lower socioeconomic status (SES) is associated with a higher prevalence of comorbidities and mortality. The association between SES and mortality, as well as the effect-modifying role of specific comorbidities, are not yet fully understood within the critical care context of insurance-based universal healthcare systems. To inform health policy and practice, we examined socioeconomic disparities in Dutch ICU admissions, considering comorbidities in the context of hospital mortality.

DESIGN

Nationwide retrospective cohort study.

SETTING

All 79 Dutch ICUs were included.

PATIENTS: We used data from 588,568 ICU admissions (2014-2022) linked with household-level SES data.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN

RESULTS

We used mixed-effects logistic regression models to investigate the association between SES quintiles and hospital mortality. We adjusted models for age, sex, year of admission, acute physiologic derangement, and comorbidities. Also, we investigated the effect-modifying role of seven comorbidities: respiratory insufficiency, renal insufficiency, cancer, cardiovascular insufficiency, diabetes mellitus, cirrhosis, and immunological insufficiency. Unadjusted odds ratios (ORs) for hospital mortality were higher among patients with lower SES. After adjustment, SES quintiles remained significantly different from the middle quintile, with attenuated ORs (95% CI): 1.6 (1.5-1.6), 1.1 (1.0-1.1), 1.0 (0.9-1.0), and 0.9 (0.9-1.0), respectively. The association was most pronounced in the lowest SES quintile and persisted in patients with and without specific comorbidities.

CONCLUSIONS

ICU patients with a lower SES face poorer survival prospects, irrespective of comorbidities. This highlights the persistent health disparities that may influence ICU outcomes. SES should be considered for interpreting outcome measures, designing healthcare policies, and targeting interventions to improve health equity.