Long-term outcomes and clinical predictors of hospital mortality in very long stay intensive care unit patients: a cohort study

Abstract

Introduction: Little information is available on prognosis and outcomes of very long stay intensive care unit (ICU) patients. The purpose of this study was to identify long-term outcomes after hospital discharge and readily available clinical predictors of hospital mortality for patients requiring prolonged care in the ICU.

Method: Clinical data were collected from consecutive patients requiring at least 30 days of ICU care admitted over 3 calendar years (2001 to 2003) to a medical/surgical ICU in a university-affiliated tertiary care centre.

Results: A total of 182 patients met the inclusion criteria, with a mean age of 63 years, median ICU stay of 48.5 days (interquartile range 36-78 days) and ICU mortality of 32%. They accounted for 8% of total admissions and 48% of total occupied beds. Of these patients, 42% died in hospital, 44% returned to their previous place of residence, and 14% were transferred to long-term care institutions. By 6 months after hospital discharge a further 8% of the patients had died, 40% remained at their previous place of residence, and 10% were in long-term care. Predictors of hospital mortality, identified using multivariate logistic regression, included age (odds ratio [OR] 1.45 per additional decade, 95% confidence interval [CI] 1.10-1.91), any immunosuppression (OR 5.2, 95% CI 1.7-15.5), mechanical ventilation for longer than 90 days (OR 4.0, 95% CI 1.3-12.0), treatment with inotropes or vasopressors for more than 3 days at or after day 30 in the ICU (OR 7.1, 95% CI 2.6-19.3), and acute renal failure requiring dialysis at or after day 30 in the ICU (OR 6.3, 95% CI 2.0-19.7).

Conclusion: Patients with very long stays in the ICU appear to have a reasonable chance of survival, with most survivors in our cohort residing at their previous place of residence 6 months after hospital discharge. Prolonged requirement for life support therapies (ventilation, vasoactive agents, or acute dialysis) and a limited number of pre-existing co-morbidities (immunosuppression and, to a lesser extent, patient age) were predictors of increased hospital mortality. These predictors may assist in clinical decision making for this resource intensive patient population, and their reproducibility in other very long stay patient populations should be explored.

Figure 1

Hospital survival by number of ICU days. ICU, intensive care unit; se, standard error.

Figure 2

Hospital survival by number of ventilator days. se, standard error.

Figure 3

Hospital survival by number of ICU readmissions during the hospital stay. ICU, intensive care unit; se, standard error.

Figure 4

Hospital survival by number of non-age-related clinical predictors identified by multivariate logistic regression analysis. ICU, intensive care unit; se, standard error.