Respiratory viral testing and antibacterial treatment in patients hospitalized with community-acquired pneumonia

Abstract

Objective: Viruses are more common than bacteria in patients hospitalized with community-acquired pneumonia. Little is known, however, about the frequency of respiratory viral testing and its associations with antimicrobial utilization.

Design: Retrospective cohort study.

Setting: The study included 179 US hospitals.

Patients: Adults admitted with pneumonia between July 2010 and June 2015.

Methods: We assessed the frequency of respiratory virus testing and compared antimicrobial utilization, mortality, length of stay, and costs between tested versus untested patients, and between virus-positive versus virus-negative patients.

Results: Among 166,273 patients with pneumonia on admission, 40,787 patients (24.5%) were tested for respiratory viruses, 94.8% were tested for influenza, and 20.7% were tested for other viruses. Viral assays were positive in 5,133 of 40,787 tested patients (12.6%), typically for influenza and rhinovirus. Tested patients were younger and had fewer comorbidities than untested patients, but patients with positive viral assays were older and had more comorbidities than those with negative assays. Blood cultures were positive for bacterial pathogens in 2.7% of patients with positive viral assays versus 5.3% of patients with negative viral tests (P < .001). Antibacterial courses were shorter for virus-positive versus -negative patients overall (mean 5.5 vs 6.4 days; P < .001) but varied by bacterial testing: 8.1 versus 8.0 days (P = .60) if bacterial tests were positive; 5.3 versus 6.1 days (P < .001) if bacterial tests were negative; and 3.3 versus 5.2 days (P < .001) if bacterial tests were not obtained (interaction P < .001).

Conclusions: A minority of patients hospitalized with pneumonia were tested for respiratory viruses; only a fraction of potential viral pathogens were assayed; and patients with positive viral tests often received long antibacterial courses.

Figures

Fig. 1.

Proportions of patients receiving antibacterial and antiviral therapies on hospital days 1 and 3, by performance and result of antiviral testing. Comparisons of same-day antibiotic and antiviral utilization fractions between patients who did and did not receive antiviral testing, and between those with positive and negative antiviral tests, were statistically significant (P < .001) with the exception of day 3 antibiotic utilization by receipt of antiviral test (P = .58).

Fig. 2.

Average duration of antibacterial treatment among patients hospitalized with pneumonia as a function of all bacterial and viral test results. Box plots of duration of antibacterial treatment amongst patients hospitalized with pneumonia by use of viral testing and bacterial and viral test results. Each box encompasses the range between the lower (25%) and upper (75%) quartiles, with the median marked by horizonal line and the mean marked by a circle. The whiskers of each box extend from minimum to maximum treatment days, here truncated at 10 days due to the high right-skewing of the length of stay distributions, as indicated by the tabulated maxima. Note. Circles: means; whiskers: ranges; the bottom and top edges of the boxes: interquartile range; horizontal lines in the boxes: median.