Critically ill elderly who require mechanical ventilation: the effects of age on survival outcomes and resource utilisation in the medical intensive care unit of a general hospital

Abstract

Introduction: Advanced age has been a criterion for denying admission to the medical intensive care unit (MICU) due to the perceived poorer outcome and increased resource utilisation. We studied the relationship between age and outcome of the critically ill mechanically-ventilated patients admitted to the MICU.

Materials and methods: This prospective study included patients admitted to the MICU for mechanical ventilation between 1994 and 1998. These were divided into 2 cohorts, with 206 patients aged 65 and above and 159 below 65 years. Outcome measures were MICU and hospital mortality and length of stay (LOS) in the MICU and hospital. Logistic and linear regression analyses were performed to determine the association between age and MICU and hospital mortality, as well as MICU and hospital LOS. Factors adjusted for included gender, smoking history, pre-hospitalisation functional status, ambulatory status, use of inotropes and APACHE II (m) scores (APACHE II scores were modified to exclude age points).

Results: Multivariate analysis revealed no statistically significant relationship between age and MICU or hospital mortality and LOS. However, APACHE IIM scores were significantly related to both MICU and hospital mortality (OR, 1.1; CI, 1.07-1.14 and OR, 1.1; CI, 1.09-1.18 respectively), but did not predict MICU or hospital LOS.

Conclusion: Severity of acute illness and chronic co-morbidities, but not age, are predictors of MICU and hospital mortality in elderly ventilated patients.