Independent validation of APACHE II severity of illness score for predicting mortality in patients with breast cancer admitted to the intensive care unit.

BACKGROUND

To determine the validity and predictive accuracy of the Acute Physiology and Chronic Health Evaluation (APACHE II) scoring system for severity of illness by comparing the actual hospital mortality with the predicted mortality for patients with breast cancer admitted to the intensive care unit (ICU).

METHODS

APACHE II scores were calculated based on retrospective evaluation of the medical records of 52 patients with breast cancer who received ICU care. The relationships between hospital mortality and APACHE II scores, number of sites of metastatic disease, duration of metastatic disease, number of chemotherapeutic regimens given for metastatic disease, presence of neutropenia or thrombocytopenia, age, reason for ICU admission, and length of ICU stay were assessed.

RESULTS

Twenty-two patients (42%) died during the hospital stay during in which they were admitted to the ICU. Predicted mortality based on a logistic regression model using APACHE II scores was 21 patients (40%). APACHE II specificity was 87%; sensitivity was 54%. There were significant relationships between presence of metastatic disease, number of metastatic sites, reason for ICU admission, and length of ICU stay. Patients with more than two sites of metastatic disease and those with respiratory failure had particularly poor chances of survival. Regression analysis incorporating the number of sites of metastatic disease, reason for ICU admission (whether for a pulmonary or a cardiovascular problem), and APACHE II score suggested that APACHE II could predict hospital survival.

CONCLUSIONS

This retrospective study showed that APACHE II scores were associated with hospital mortality in patients with breast cancer who were admitted to ICU. The number of metastatic sites and the type of major organ system failure were also associated with outcome. Regression analysis suggested that APACHE II scores were independently associated with survival outcome.