The longer patients are in hospital before Intensive Care admission the higher their mortality

Objective: To explore the relationship between hospital mortality and time spent by patients on hospital wards before admission to the intensive care unit (ICU). Design: Observational study of prospectively collected data. Setting: Participating intensive care units within the North East Thames Regional Database. Patients and participants: Patients, 7,190, admitted to ICU from the hospital wards of 24 hospitals. Interventions: None. Measurements and results: Of ICU admissions from the wards, 40.1% were in hospital for more than 3 days and 11.7% for more than 15 days. ICU patients who died in hospital were in-patients longer ( p=0.001) before admission ( median 3 days; interquartile range 1 - 9) than those discharged alive ( median 2 days; interquartile range 1 - 5). Hospital mortality increased significantly ( p< 0.0001) in relation to time on hospital wards before ICU: 47.1% ( standardised mortality ratio 1.09) for patients in hospital 0 - 3 days before ICU admission up to 67.2% ( standardised mortality ratio 1.39) for patients on the wards for more than 15 days before ICU. Length of stay before ICU admission was an independent predictor of hospital mortality odds ratio per day 1.019; 95% confidence interval 1.014 - 1.024). There were significant differences (p< 0.001) in patient age, APACHE II score and predicted mortality in relation to time on wards before ICU admission. Conclusions: Mortality was high among patients admitted from the wards to ICU; many were inpatients for days or weeks before admission. The longer these patients were in hospital before ICU admission, the higher their mortality. Patients with delayed admission differed in some respects compared to those admitted earlier.