Comparison of APACHE II and III scoring systems for mortality prediction in critical surgical illness.

OBJECTIVE

To determine whether the Acute Physiology and Chronic Health Evaluation III (APACHE III), an updated version of APACHE II that contains a larger number of postoperative patients in the normative database, offers better prediction in critical surgical illness.

DESIGN

Prospective cohort study.

SETTING

Surgical intensive care unit of an urban, tertiary-care university hospital.

PARTICIPANTS

Eight hundred forty-four consecutive patients in the surgical intensive care unit. Overall scores were determined, as well as scores for survivor, nonsurvivor, trauma, nontrauma, postoperative, and nonoperative patient subgroups.

MAIN OUTCOME MEASURES

Survival to hospital discharge, and survival compared with published normative APACHE II and III databases.

RESULTS

Mean age was 65.1 +/- 0.5 years. Overall mortality was 7.0% in the surgical intensive care unit and 9.1% in the hospital. The relationship between APACHE II and APACHE III scores for individual patients was linear and correlated significantly (P < .0001) (range of correlation coefficients, .72 to .86) overall and in all subgroups. Both scoring systems overestimated our mortality, but estimations made by APACHE III were significantly (P < .01) higher overall and in all subgroups.

CONCLUSIONS

In institutions or groups of patients where APACHE II underestimates mortality, APACHE III may be corrective. However, the differences are subtle and may be difficult to detect in smaller studies.