Factors associated with life-sustaining treatment restriction in a general intensive care unit

Few previous studies have investigated associations between clinical variables available after 24 hours in the intensive care unit (ICU), including the Charlson Comorbidity Index (CCI), and decisions to restrict life-sustaining treatment. The aim of this study was to identify factors associated with the life-sustaining treatment restriction and to explore if CCI contributes to explaining decisions to restrict life-sustaining treatment in the ICU at a university hospital in Norway from 2007 to 2009.

Patients' Simplified Acute Physiology Score II (SAPS II), age, sex, type of admission, and length of hospital stay prior to being admitted to the unit were recorded. We retrospectively registered the CCI for all patients based on the medical records prior to the index stay. A multivariable logistic regression analysis was used to assess factors associated with treatment restriction during the ICU stay.

We included 936 patients, comprising 685 (73%) medical, 204 (22%) unscheduled and 47 (5%) scheduled surgical patients. Treatment restriction was experienced by 241 (26%) patients during their ICU stay. The variables that were significantly associated with treatment restriction in multivariable analysis were older age (odds ratio [OR] = 1.48 per 10 years, 95% confidence interval [CI] = 1.28-1.72 per 10 years), higher SAPS II (OR = 1.05, 95% CI = 1.04-1.07) and CCI values relative to the reference of CCI = 0: CCI = 2 (OR = 2.08, 95% CI = 1.20-3.61) and CCI≥3 (OR = 2.72, 95% CI = 1.65-4.47).

In multivariable analysis, older age, greater illness severity after 24 h in the ICU and greater comorbidity at hospital admission were independently associated with subsequent life-sustaining treatment restriction. The CCI score contributed additional information independent of the SAPS II illness severity rating.