Combination antiviral and antibiotic therapy in U.S. veterans with influenza was associated with reductions in all-cause and respiratory hospitalizations in a recent retrospective study.
Researchers used data from the Veterans Affairs Informatics and Computing Infrastructure to look at patients with clinical encounters related to laboratory-confirmed influenza from January 2011 through January 2019. They compared all-cause and respiratory hospitalizations within 30 days of influenza diagnosis among patients who received no treatment, an antiviral, an antibiotic, or an antiviral plus an antibiotic. Participants were diagnosed in a primary care setting or an ED, were not transferred to the ED, had no hospitalization in the 30 days prior to influenza diagnosis, were not admitted to the hospital on the same day as influenza diagnosis, and had vital sign data from the day of diagnosis. Results were published online on Jan. 24 by Clinical Infectious Diseases.
Of 12,806 study participants with influenza, 4,228 received no treatment, 6,492 received an antiviral only, 671 received an antibiotic only, and 1,415 received an antiviral plus an antibiotic. Most of the influenza diagnoses occurred in the ED. The top antibiotic classes used were macrolides, penicillin, quinolones, and tetracyclines, and oseltamivir was the primary antiviral used (99.9%). The antiviral-plus-antibiotic cohort had the highest Charlson Comorbidity Index (1.62), and the antiviral cohort had the lowest (1.35).
The untreated cohort had the highest proportion of all-cause hospitalizations (10.48%), and the antiviral-plus-antibiotic cohort had the lowest (3.18%). Results were similar for respiratory hospitalizations, with the highest proportion among the untreated cohort (6.58%) and the lowest in the antiviral-plus-antibiotic cohort (1.06%). Compared to untreated patients, those who received an antiviral had a 63% lower risk of all-cause hospitalization within 30 days (relative risk [RR], 0.37; 95% CI, 0.32 to 0.44), the antibiotic-only cohort had a 57% lower risk (RR, 0.43; 95% CI, 0.31 to 0.62), and the antiviral-plus-antibiotic cohort had a 72% lower risk (RR, 0.28; 95% CI, 0.21 to 0.38). The drugs appeared most protective in the first five days
Although the antiviral-plus-antibiotic group had a lower risk of all-cause hospitalization than those who received an antiviral alone, the CIs crossed 1 for each time point (adjusted RR, 0.67 [95% CI, 0.41 to 1.11] for 1 to 5 days, 0.67 [95% CI, 0.44 to 1.01] for 1 to 10 days, and 0.73 [95% CI, 0.53 to 1.01] for 1 to 30 days). Results were similar for respiratory hospitalizations, except that the combination intervention was associated with a significantly lower risk than an antiviral alone at 30 days (adjusted RR, 0.53; 95% CI, 0.31 to 0.94). Subgroup analysis showed that patients ages 65 years and older with chronic pulmonary disease had a lower risk of respiratory hospitalization with combination antiviral and antibiotic therapy compared to antiviral therapy alone.
Among other limitations, the study authors noted that their analyses were observational and based on a claims database. They added that the study population was predominantly white and male, with a mean age between 57 and 60 years; therefore, the results may not be generalizable to other patient groups. The results demonstrate that there may be a role for combination antibiotic and antiviral therapy in select patients with confirmed influenza, the authors concluded. However, “We are not recommending systematic use of combination treatment and the results should not drive a change in practice for influenza at this time,” they wrote.