To evaluate the short-term and long-term outcomes of patients with suspected bacteremia, we performed a prospective cohort study.
Clinical data were collected within 24 hours of initial culture from a random sample of 1516 episodes in which blood cultures were performed in an urban tertiary care hospital. One hundred forty-two patients with bacteremia were compared with two comparison groups: (1) 142 randomly selected patients with negative cultures, matched in age within 5 years, gender, severity of underlying disease, and presence of major comorbidity, and (2) all 155 patients with contaminant cultures. The main outcome measures were death, death secondary to bacteremia, and major complications.
In the 439 patients, there were 142 deaths (32%), 114 at 1 year (26%) and 46 within 30 days (11%). Mortality at 30 days was most highly correlated with predicted fatality of underlying disease: 48% for the 65 patients with a rapidly fatal disease, 9% for the 156 patients with an eventually fatal disease, and 0.5% for the 217 patients with no fatal disease. In a Cox survival analysis, the risk ratio associated with bacteremia was 1.6 (95% confidence interval, 1.0 to 2.4) vs the comparison groups. When we performed time-dependent Cox analyses in which the hazard ratio was allowed to change at 30 days, we found that the risk ratios associated with bacteremia were 2.3 (95% confidence interval, 1.2 to 4.4) for the first 30 days, and 1.3 (95% confidence interval, 0.76 to 2.1) after 30 days.
We conclude that this population has a high mortality, which is strongly correlated with severity of underlying disease. Short-term mortality was higher in patients with bacteremia even after controlling for severity of illness, but the increase in risk was present only during the first month and most deaths occurred in patients with a rapidly fatal disease.(Arch Intern Med. 1995;155:593-598)