Skip to main content

Length of hospital stay prior to ICU admission and outcome


We hypothesised that for the general ICU population, a longer length of hospital stay prior to ICU admission was associated with a poor outcome. Previous work in specific ICU populations has suggested that a longer length of hospital stay prior to ICU admission is associated with a higher mortality [1, 2], and longer and therefore more costly ICU stays [3]. We undertook an evaluation of the relationship between pre-ICU length of hospital stay (LOS), and hospital mortality over a 1-year period.


Using prospectively collected data, we undertook a retrospective evaluation of all patients admitted to the ICU of Glasgow Royal Infirmary from 1 August 2008 to 1 August 2009. Patients were identified from Wardwatcher (Critical Care Audit Ltd). Only the initial event was included in those patients with readmissions during the same hospital stay. The patients were divided into hospital survivors (Group A) and nonsurvivors (Group B). Statistical analysis was performed using SPSS version 15.0 for Windows (SPSS Inc, Chicago, IL, USA). Medians, interquartile ranges (IQRs) and Mann-Whitney U tests were applied as appropriate.


A total of 419 patients were admitted during the study period. After excluding those with missing data and the outliers, 397 were included in the data analysis. There were 268 in the survivor group (Group A), and 129 in the group that died (Group B). Median patient age: Group A, 50 (IQR 36 to 66), Group B, 62 (IQR 50 to 70), P < 0.001. Median APACHE II scores: Group A, 15 (IQR 10 to 20), Group B, 23 (IQR 18 to 29), P < 0.001. Median predicted hospital mortality (%): Group A, 15.9 (IQR 6.3 to 31.6), Group B, 46.8 (IQR 30.8 to 67.4), P < 0.001. Median pre-ICU LOS (days): Group A, 1 (IQR 0 to 2), Group B, 1 (IQR 0 to 4), P = 0.001. Median ICU LOS (days): Group A, 2 (IQR 1 to 6), Group B, 2 (IQR 1 to 7), P = 0.297. Median hospital LOS (days): Group A, 18 (IQR 7 to 36), Group B, 8 (IQR 3 to 23), P < 0.001.


In our cohort, the critically ill patients who survived to hospital discharge were younger, were less severely unwell and had a significantly shorter length of stay prior to ICU admission. What cannot be determined from this study is the bias of individual clinicians when seeing referrals. Assuming we admit the patients we anticipate to have the best chance of hospital survival, patients with a longer length of hospital stay prior to ICU appear to have worse outcomes.


  1. Woodhead M, et al.: Crit Care. 2006,10(Suppl 2):S1. 10.1186/cc4927

    Article  PubMed Central  PubMed  Google Scholar 

  2. Hampshire P, et al.: Crit Care. 2009, 13: R137. 10.1186/cc8016

    Article  PubMed Central  PubMed  Google Scholar 

  3. Higgins T, et al.: Crit Care Med. 2003, 31: 45-51. 10.1097/00003246-200301000-00007

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Cite this article

Simpson, K., Williams, G. & Quasim, T. Length of hospital stay prior to ICU admission and outcome. Crit Care 15 (Suppl 1), P465 (2011).

Download citation

  • Published:

  • DOI:


  • Hospital Stay
  • Hospital Mortality
  • Longe Length
  • Royal Infirmary
  • Hospital Survival