Association of Age With Short-term and Long-term Mortality Among Patients Discharged From Intensive Care Units in France

Abstract

Importance: An aging population is increasing the need for intensive care unit (ICU) beds. The benefit of ICU admission for elderly patients remains a subject of debate; however, long-term outcomes across all adult age strata are unknown.

Objective: To describe short-term and long-term mortality (up to 3 years after discharge) across age strata in adult patients admitted to French ICUs.

Design, setting, and participants: Using data extracted from the French national health system database, this cohort study determined in-hospital mortality and mortality at 3 months and 3 years after discharge of adult patients (older than 18 years) admitted to French ICUs from January 1 to December 31, 2013, focusing on age strata. The dates of analysis were November 2017 to December 2018.

Exposure: Intensive care unit admission.

Main outcomes and measures: In-hospital mortality and mortality at 3 months and 3 years after hospital discharge.

Results: The study included 133 966 patients (median age, 65 years [interquartile range, 53-76 years); 59.9% male). Total in-hospital mortality was 19.0%, and 3-year mortality was 39.7%. For the 108 539 patients discharged alive from the hospital, 6.8% died by 3 months, and 25.8% died by 3 years after hospital discharge. After adjustment for sex, comorbidities, reason for hospitalization, and organ support (invasive ventilation, noninvasive ventilation, vasopressors, inotropes, fluid resuscitation, blood products administration, cardiopulmonary resuscitation, renal replacement therapy, and mechanical circulatory support), risk of mortality increased progressively across all age strata but with a sharp increase in those 80 years and older. In-hospital and 3-year postdischarge mortality rates, respectively, were 30.5% and 44.9% in patients 80 years and older compared with 16.5% and 22.5% in those younger than 80 years. Total 3-year mortality was 61.4% among patients 80 years and older vs 35.1% in those younger than 80. After age and sex standardization, excess mortality was highest among young patients during their first year after hospital discharge and persisted into the second and third years. In contrast, the mortality risk was close to the general population risk among elderly patients (≥80 years). Age and reason for hospitalization were strongly associated with long-term mortality (9-, 13-, and 20-fold increase in the risk of death 3 years after ICU discharge in patients aged 80-84, 85-89, and ≥90 years, respectively, compared with patients aged <35 years), while organ support use during ICU showed a weaker association (all organ support had 1.3-fold or lower increase in the risk of death).

Conclusions and relevance: Results of this study suggest that aging was associated with an increased risk of mortality in the 3 years after hospital discharge that included an ICU admission, with a sharp increase in those 80 years and older. However, compared with the general population matched by age and sex, excess long-term mortality was high in young surviving patients but not in elderly patients.

Figure 1.. Kaplan-Meier Survival Curves of All Patients Since Hospital Admission and Hospital Discharge

Survival is shown by age category.

Figure 2.. Mortality Rate and Standardized Mortality Ratio (SMR) in the First Year, Second Year, and Third Year After Hospital Discharge, by Age Category

Error bars indicate 95% CIs.

Figure 3.. Association Between Age and Mortality After Adjustment for Sex, Comorbidities, Reason for Hospitalization, and Organ Support

OR indicates odds ratio. Error bars represent 95% CIs, and the dashed line shows an OR of 1.