Antibiotic Utilization and Opportunities for Stewardship Among Hospitalized Patients With Influenza Respiratory Tract Infection

Hospitalized influenza patients are often treated with antibiotics empirically while awaiting final diagnosis. The goal of this study was to describe the inappropriate continuation of antibiotics for influenza respiratory tract infections (RTIs).

We retrospectively studied adults admitted to our institution over 2 respiratory flu seasons with positive influenza RTIs. Inappropriate antibiotic duration (IAD) was defined as antibiotic use for >24 hours after a positive influenza test in patients presenting with <72 hours of RTI symptoms and with no other indications of bacterial infection.

During the study period, 322 patients included in this study were admitted for influenza RTI. Respiratory cultures were ordered for 50 of these patients (15.5%) and 71 patients (22%) had a positive chest x-ray, but antibiotics were prescribed to 211 patients (65.5%) on admission. Antibiotics were inappropriately continued in 73 patients (34.5%). Patients receiving IAD had a longer length of stay (LOS) (median, 6 days; range, 4-9 days) compared with those whose antibiotics were discontinued appropriately (median, 5 days; range, 3-8 days) and those who were not treated with antibiotics (median, 4 days; range, 3-6 days; P<.001). However, mortality was similar among these 3 groups: 3 patients (4.1%) from the IAD cohort died; 6 patients (4.3%) from the group with an appropriate antibiotic duration died; and 2 patients [1.8%] from the group given no antibiotics died (P=.510). The 30-day readmission rates were similar as well: 9 patients (12.3%) from the IAD group were readmitted within 30 days; 21 patients (15.2%) from the group with appropriate antibiotic duration were readmitted; and 11 patients (9.9%) from the group given no antibiotics were readmitted (P=.455). Total hospital costs were greater in patients treated with IAD ($10,645; range, $6,485-$18,035) compared with the group treated with appropriate antibiotic duration ($7,479; range, $4,866-$12,922) and the group given no antibiotics $5,961 (range, $4,711-$9,575). Thus, the hospital experienced a median loss in net hospital revenue of $2,076 per IAD patient compared with a patient for which antibiotic duration was appropriate.

The majority of patients with influenza RTI received antibiotics on admission, and 34.5% were inappropriately continued on antibiotics without evidence of bacterial infection, which led to increased LOS, loss of net revenue, and no improvement in outcome. Thus, stewardship initiatives aimed at this population are warranted.