[Bacteremia in very elderly patients: risk factors, clinical characteristics and mortality]. / Bacteriemia en pacientes muy ancianos: factores de riesgo, características clínicas y mortalidad.

INTRODUCTION: There is little information on bacteremia in very elderly patients. This study describes the characteristics of bacteremia in this population. METHODS: This is a prospective study investigating bacteremia episodes in patients over 80 years old in comparison with episodes in patients aged 18-64 and 65-79 years. RESULTS: A total of 146 bacteremia episodes were analyzed in patients over 80 years old. Comorbidity was documented in 66.4% and immunodeficiency in 6.8% of patients. Among the total, 82.2% had no underlying disease or a disease considered non-fatal. Eighty episodes were community-acquired. The main infectious foci included primary (25.3%) and urinary tract (20.5%) infection, and the most frequent isolates were Escherichia coli (28.2%), coagulase-negative Staphylococcus (14.7%) and S. aureus (13.6%). Sepsis or septic shock occurred in 55.5% of the cases, and 31 patients died due to a bacteremia-related cause. Immunodeficiency was less frequent in patients over 80 years old, but they had a higher proportion of community-acquired infections and gram-negative infections. Bacteremia-related mortality was highest in the oldest group of patients and was associated with a fatal or ultimately fatal underlying disease, S. aureus infection, and inappropriate empirical antibiotic treatment. A lower Pitt severity score was related to lower mortality risk. CONCLUSIONS: Very elderly bacteremic patients showed a lower frequency of immunodeficiency, a higher percentage of community-acquired and gram-negative infections. Bacteremia-related mortality was greater in the most elderly group and was associated with fatal or ultimately fatal underlying disease, S. aureus infection and initiation of inappropriate empirical antibiotic treatment.