Bacteremia among elderly patients: relationship between age, comorbidity and mortality

Evaluation of: Sogaard M, Sconheyder HC, Riis A, Sorensen HT, Norgaard M: Short-term mortality in relation to age and comorbidity in older adults with community-acquired bacteremia: a population-based cohort study. J. Am. Geriatr. Soc. 56(9), 1593–1600 (2008). It is widely recognized that aging has an independent negative impact on the outcome of infectious diseases, including bacteremia. It is also well known that the number of comorbid conditions increase with age. However, age alone is inadequate to represent an individuals comorbidity owing to the significant variability in the number and severity of comorbidities among the elderly. It is presumed that comorbidity alone always accounts for increased mortality of infectious diseases (i.e., bacteremia) accompanied with increasing age. However, the study by Sogaard et al. does not support this presumption. This finding cannot be explained only by incompleteness of comorbidity indices used. Coexistence of comorbidity and other factors, such as functional and nutritional status, and the possibility of variable interactions among them, make evaluation of their impact on certain health-status outcomes extremely challenging.