Effects of education, income and employment on ICU and post-ICU survival - A nationwide Swedish cohort study of individual-level data with 1-year follow up.

Purpose: The aim of this study was to examine relationships between education, income, and employment (socioeconomic status, SES) and intensive care unit (ICU) survival and survival 1 year after discharge from ICU (Post-ICU survival).

Methods: Individual data from ICU patients were linked to register data of education level, disposable income, employment status, civil status, foreign background, comorbidities, and vital status. Associations between SES, ICU survival and 1-year post-ICU survival was analysed using Cox's regression.

Results: We included 58,279 adults (59% men, median length of stay in ICU 4.0 days, median SAPS3 score 61). Survival rates at discharge from ICU and one year after discharge were 88% and 63%, respectively. Risk of ICU death (Hazard ratios, HR) was significantly higher in unemployed and retired compared to patients who worked prior to admission (1.20; 95% CI: 1.10-1.30 and 1.15; (1.07-1.24), respectively. There was no consistent association between education, income and ICU death. Risk of post-ICU death decreased with greater income and was roughly 16% lower in the highest compared to lowest income quintile (HR 0.84; 0.79-0.88). Higher education levels appeared to be associated with reduced risk of death during the first year after ICU discharge.

Conclusions: Significant relationships between low SES in the critically ill and increased risk of death indicate that it is important to identify and support patients with low SES to improve survival after intensive care. Studies of survival after critical illness need to account for participants SES.