Community-acquired bacteremia at a teaching versus a nonteaching hospital: impact of acute severity of illness on 30-day mortality.

BACKGROUND

Few studies have focused recently on the epidemiology of community-acquired bacteremia (CAB) and there have been few comparisons of CAB in teaching versus nonteaching hospitals.

OBJECTIVES

To compare the clinical characteristics, acute severity of illness, and 30-day mortality of patients with CAB admitted to a teaching and a nonteaching hospital and to define predictors of 30-day mortality among patients with CAB that would be identifiable at the time of admission to the hospital.

METHODS

This was a retrospective study of CAB at a teaching hospital (n = 174 episodes) compared to a community nonteaching hospital (n = 74 episodes) during 1995. Data collected included demographic characteristics, underlying diseases, sources of CAB, and antimicrobial therapy. Acute severity of illness on admission was measured by using the acute physiology score component of the Acute Physiology and Chronic Health Evaluation III system (APS APACHE III).

MAIN OUTCOME MEASURE

Status, dead or alive, 30 days after admission for CAB.

RESULTS

At the nonteaching hospital, patients were older but, on average, significantly less acutely ill (as measured by the admission APS APACHE III score) than were those at the teaching hospital. In contrast, patients with HIV infection, posttransplantation, or on hemodialysis were identified only at the teaching hospital. Overall, organisms causing CAB at both hospitals were similar except that Staphylococcus aureus CAB occurred significantly more often at the teaching hospital and Escherichia coli CAB occurred more often at the nonteaching hospital. There was no significant difference in 30-day mortality in patients with CAB between the teaching hospital (19.3%) and the nonteaching hospital (16.7%; P =.63). APS APACHE III score on admission identified episodes of CAB with a low- and a high-risk for 30-day mortality at both hospitals. Independent predictors of 30-day mortality were APACHE III score on admission (P <.001) and pneumonia as a source of CAB (P =.012).

CONCLUSIONS

Among patients with CAB, acute severity of illness on admission was the most important predictor of 30-day mortality at both hospitals. Even though patients with CAB were, on average, more severely ill at the time of admission to the teaching hospital, 30-day mortality rates were not significantly different between the two hospitals because deaths correlated with high APS APACHE III scores at both facilities. The APS APACHE III score on admission provides important prognostic information among patients with CAB.