Attributable mortality rate and duration of hospital stay associated with enterococcal bacteremia

Abstract

The mortality rate of patients with cases of enterococcal bacteremia is high, although it has often been related to the patients' underlying conditions rather than to the infection itself. To analyze the attributable prognosis of enterococcal bacteremia (assessed by its attributable mortality rate and duration of hospital stay), a prospective, matched case-control study was done. All adults with an episode of enterococcal bacteremia without endocarditis were included. A control patient was randomly selected for every case patient and matched by sex, age and hospital ward. Univariate and multivariate analyses were performed. A total of 122 pairs were included, and incidence of enterococcal bacteremia was 2.3 episodes/1000 discharges. Crude 30-day mortality rates for case patients and control patients were 23% and 17%, respectively (P=.29); thus, the estimated attributable mortality rate was 6% (95% confidence interval, -4% to 16%). The mean duration of hospital stay of case patients and control patients were 38 and 17 days, respectively (P<.001); thus, the estimated attributable duration of hospital stay was 21 days (95% CI, 7-32 days). Enterococcal bacteremia without endocarditis does not increase risk of death by itself but extends the duration of hospital stay of patients who develop it.