[Bacteremia in the elderly. Clinical features and prognostic factors]

The analysis of the most relevant characteristics and prognostic factors in elderly patients with bacteremia.

For the period 1989-1993 a prospective study of all significant bacteremias in adult patients admitted to a General Hospital was performed. Patients were visited until their death or during at least 50 days. The most relevant findings in elderly patients (over 65 years old) are described. Overall survival probabilities were obtained by Kaplan-Merner analysis. Cox proportional models were used to examine hazards of dying.

Of the 1,128 bacteremias studied, 603 (53.9%) were in elderly patients. In this group, the increasing age was related with higher frequency of urinary (p = 0.02) and biliary (p = 0.001) sources of infection and lower frequency of underlying neoplasia (p = 0.06), immunosuppression (p = 0.0000) and development of septic shock (p = 0.02). These differences are higher in patients over 85. Among older patients the survival probability in the day 21 after diagnosis was 0.71 (95% CI 0.66-0.74), significantly lower to the probability in younger patients (p = 0.0001). In the elderly patients, the worse prognestic was associated to shock (RR = 8; 95% CI 5.8-11), indeterminated source of infection (RR = 3.6; 95% CI 2.2-5.8), underlying neoplasia (RR = 1.7; 95% CI 1.3-2.4), neutropania (RR = 1.5; 95% CI 1.1-2.1) nosocomial acquisition (RR = 1.3; 95% CI 1.0-3.1) and inappropriate treatment (RR = 1.2; 95% CI 1.0-3.2), but age was not an independent contributor.

We found differences between the clinical characteristics and the prognosis of bactermia in elderly and younger patients. Among elder patients, those over 85 years old constitute a particular group with well defined characteristics.