Development of demographics and outcome of very old critically ill patients admitted to intensive care units

Abstract

To evaluate the development of demographics and outcome of very old (>80 years) critically ill patients admitted to intensive care units. All consecutive patients admitted to 41 Austrian intensive care units (ICUs) over an 11-year period. We performed a retrospective cohort study of prospectively collected data. To compare parameters over time, patients were divided into three groups (group I from 1998 until 2001, group II from 2002 to 2004, and group III from 2005 to 2008). A total of 17,126 patients older than 80 years of age were admitted over the study period. The proportion of very old patients increased from 11.5% (I) to 15.3% (III) with a significant higher prevalence of females in all groups (on average 63.2%). Severity of illness also increased over time, even when corrected for age. Use of noninvasive mechanical ventilation increased over the years. However, risk-adjusted mortality rates [observed-to-expected (O/E) ratios] decreased from 1.14 [confidence interval (CI) 1.11-1.18] to 1.02 (CI 0.99-1.05). This improvement in outcome was confirmed on multivariate analysis: for every year delay in ICU admission, the odds to die decreased by 3%. Moreover, females exhibited a better outcome compared with males. The relative and absolute numbers of very old patients increased over the study period, as did the severity of illness. Despite this, risk-adjusted hospital mortality improved over the study period. Females dominated in the very old patients and exhibited moreover a better outcome compared with males.