Background: Recommendations for diagnostic testing in hospitalized patients with community-acquired pneumonia remain controversial. We aimed to evaluate the impact of a therapeutic strategy based on the microbiological results provided by urinary antigen tests for Streptococcus pneumoniae and Legionella pneumophila.
Methods: For a 2 year period, hospitalized patients with community-acquired pneumonia were randomly assigned to receive either empirical treatment, according to international guidelines, or targeted treatment, on the basis of the results from antigen tests. We compared outcome parameters, monetary costs and antibiotic exposure levels.
Results: Out of 194 enrolled patients, 177 were available for randomization; 89 were assigned to empirical treatment, and 88 were assigned to targeted treatment. Targeted treatment was associated with a slightly higher overall cost (1657.00 versus 1617.20 euros, p= 0.28), reduction in the incidence of adverse events (9 versus 18%, p= 0.12) and lower exposure to broad-spectrum antimicrobials (154.4 versus 183.3 DDD/100PD). No statistically significant differences in other outcome parameters were observed. Oral antibiotic treatment was started according to the results of antigen tests in 25 patients assigned to targeted treatment; these patients showed a statistically significant higher risk of clinical relapse as compared to the remaining population (12 versus 3%, p= 0.04).
Conclusions: The routine implementation of urine antigen detection tests does not carry substantial outcome-related or economic benefits to hospitalized patients with community-acquired pneumonia. Narrowing the antibiotic therapy according to the urine antigen results may in fact be associated with a higher risk of clinical relapse.