The CDC has reported that seasonal influenza in 2017-18 has been one of the worst on record, with hospitalization rates among the highest recorded, especially among younger age groups (age 50-65, hospitalization rate of 63.1 per 100,000 people compared to 35.1 in last severe season, 2015-6). Understanding how antiviral use affects rates and severity of complications is important to inform treatment decisions. This study used real world US claims data for 3 flu seasons (2014-2016) to understand the frequency of flu complications and how intervention with antivirals may affect their occurrence.
This was a retrospective cohort study using US commercial claims data from the 2014-2016 flu seasons. Patients with a diagnosis code for flu were identified and required to have continuous coverage for at least 365 days before and 91 days after diagnosis. Patients who were prescribed antivirals within 48 hours of the first flu-related encounter during the flu season were identified and propensity score matched to a comparative cohort without antiviral use within 48 hours but comparable baseline health resource utilization (HRU) and comorbidities. All-cause and respiratory-related HRU and costs in the 30 and 91 days after flu diagnosis were analyzed and compared.
989,530 cases of influenza were identified over 3 flu seasons, with 60.2 percent receiving antiviral therapy (table 1). In the matched sample, greater HRU and costs was identified in the cohort that did not receive antiviral therapy, with 15% vs 10.4% (p<0.001) visiting the ER, and 2.8% vs 0.9% (p<0.001) being admitted for inpatient care within the 1st month (table 2). Similarly, greater HRU was also seen in respiratory-related HRU and costs in the cohorts that did not receive antiviral therapy. Findings were similar in unmatched cohorts.
In data for the last 3 available flu seasons, flu patients treated with antivirals had less complications, healthcare resource utilization and overall costs than those who did not receive antiviral treatment. Limitations with this kind of study restrict the conclusions that can be made from this analysis, however suggest that treating flu can improve outcomes and resource utilization beyond symptom resolution.
T. M. Tu, Roche: Employee , Salary .
D. Keebler, Roche: Employee , Salary .
D. Moawad, Roche: Employee , Salary .