Age distribution and clinical results of critically ill patients above 65-year-old in an aging society: A retrospective cohort study.

Abstract

Increasing age has been observed among patients admitted to the intensive care unit(ICU). Age traditionally considered a risk factor for ICU mortality. We investigated how the epidemiology and clinical outcomes of older ICU patients have changed over a decade. We analyzed patients admitted to the ICU at a university hospital in Seoul, South Korea. We defined patients aged 65 and older as older patients. Changes in age groups and mortality risk factors over the study period were analyzed. A total of 32,322 patients were enrolled who aged ≥ 65 years admitted to the ICUs between January 1, 2007, and December 31, 2017. Patients aged 65 years accounted for 35% and of these, the older(O: 65-74 yrs) comprised 19,630(66.5%), very older(VO: 75-84 yrs) group 8,573(29.1%), and very very older(VVO: 85 years) group 1,300(4.4 %). The mean age of ICU patients over the study period increased(71.9±5.6yrs in 2007 vs. 73.2±6.1yrs in 2017) and the proportions of the VO and VVO group both increased. Over the period, the proportion of female increased(37.9% in 2007 vs. 43.3% in 2017), and increased ICU admissions for medical reasons(39.7% in 2007 vs. 40.2% in 2017). In-hospital mortality declined across all older age groups, from 10.3% in 2007 to 7.6% in 2017. Hospital length of stay(LOS) decreased in all groups, but ICU LOS decreased only in the O and VO groups. The study indicates a changing demographic in ICUs with an increase in older patients, and suggests a need for customized ICU treatment strategies and resources.