Predictors of Mortality in Patients with Bacteremia: the Importance of Functional Status

Objective: To evaluate the influence of functional status on the outcome in older patients with bacteremia.

Design: Prospective study of all episodes of bacteremia that occurred in adults during a 27-month period (January 1991 to March 1993).

Setting: A 280-bed community hospital.

Participants: During the study period, bacteremia was diagnosed in 242 consecutive patients (incidence of 11.2 bacteremic episodes per 1000 hospital admissions). One hundred twenty-seven of these patients were 65 years of age or older, and 115 were less than age 65.

Measurements: On identification of a positive blood culture, data on demographics, clinical findings, and a series of factors frequently cited as predisposing to infection were collected. The patient's functional status was assessed using the Barthel index (a score of < 60 identifies moderately and highly dependent patients).

Results: The overall mortality rate was 14.9% (36 of 242). In the univariate analysis, mortality was associated significantly with age greater than 65 years, nosocomial infection, absence of fever, shock, leukocytosis or leukopenia, inappropriate therapy, more than one underlying disease, immuno-compromised state, and limited functional status. Multiple logistic regression analysis revealed that shock (OR = 27.6, 95% CI 5.7-133), a Barthel score less than 60 (OR = 11.7, 95% CI 3.2-43), nosocomial infection (OR = 6.7, 95% CI 1.8-25.5), absence of fever (OR = 5.2, 95% CI 1.05-26), and immunocompromised state (OR = 15.6, 95% CI 2.4-101.5) were significantly associated with death attributable to bacteremia.

Conclusion: The main prognostic factors in a patient with bacteremia were the presence of shock, impaired functional status, immunodeficiency state, acquisition of infection in the hospital, and absence of fever on admission. Age alone did not influence outcome.