Increased risk of death and readmission after hospital discharge of critically ill patients in a developing country: a retrospective multicenter cohort study

To describe long-term mortality and hospital readmissions of patients admitted to Brazilian intensive care units (ICU). Retrospective cohort study of adult patients admitted to Brazilian hospitals affiliated to the Public Healthcare System from 10 state capitals. ICU patients were paired to non-ICU patients by frequency matching (ratio 1:2), according to postal code and admission semester. Hospitalization records were linked through deterministic linkage to national mortality data. Primary outcome was mortality up to 1 year. Other outcomes were mortality and readmissions at 30 and 90 days and 3 years. Multiple Cox regressions were used adjusting for age, sex, cancer diagnosis, type of hospital, and surgical status. We included 324,594 patients (108,302 ICU and 216,292 non-ICU). ICU patients had increased hospital length of stay [9 (5-17) vs. 3 (1-6) days, p < 0.001] and mortality (18.5 vs. 3.6%, p < 0.001) versus non-ICU patients. One year after discharge, ICU patients were more frequently readmitted to hospital (25.4 vs. 17.4%, p < 0.001) and to ICU (31.4 vs. 7.3%, p < 0.001) than controls. Mortality up to 1 year was also higher for ICU patients (14.3 vs. 3.9%, p < 0.001). A significant interaction between surgical status and mortality was found, with adjusted hazard ratios (HRs) up to 1 year of 2.7 [95% confidence interval (CI) 2.5-2.9] for surgical patients, and 3.4 (95%CI 3.3-3.5) for medical patients. The risk for death and readmission diminished over time up to 3 years. In a public healthcare system of a developing country, ICU patients have excessive long-term mortality and frequent readmissions. The ICU burden tended to reduce over time after hospital discharge.