Reduced mortality, complications, and economic burden among medicare beneficiaries receiving influenza antivirals

Abstract

Introduction

Antiviral therapy may be underutilized in patients at high risk for increased clinical and economic burden (e.g. older adults). We aimed to examine the benefits associated with antiviral treatment of seasonal influenza among treated and untreated Medicare beneficiaries.

Methods

This retrospective study of Medicare Claims Research Identifiable Files identified patients ≥66 years old with an influenza diagnosis in outpatient setting between October 2016–March 2019 (flu seasons 2016–2018). Index date defined as date of first claim with influenza diagnosis; baseline as the 12 months pre-index. Treated patients received antivirals ≤2 days from index. Untreated patients had no antivirals ≤6 months post-index. Treated/untreated patients were 1:1 propensity score matched. Outcomes (death, all-cause and respiratory-related healthcare resource utilization [HCRU] and costs) were assessed until death or up to 6 months post-index. Descriptive statistics were reported; Kaplan-Meier estimation was used for survival over time.

Results

Among 116,901 matched patient pairs, all-cause mortality within 6 months from index diagnosis was 1.6% among treated versus 4.3% among untreated patients. Rates (treated versus untreated) of all-cause inpatient hospitalizations during follow-up were 13.9% versus 22.7% and respiratory-related hospitalizations were 4.2% versus 9.0%. Mean (SD) total all-cause and respiratory-related costs were $9,830 ($18,616.0) and $900 ($4016.4) among the treated, respectively, versus $13,207 ($24,405.1) and $2,024 ($7,623.7) among untreated, respectively. All differences were statistically significant (p < 0.001).

Conclusions

Lack of antiviral treatment is associated with increased mortality, HCRU, and economic burden in older Medicare beneficiaries with seasonal influenza. Future research should investigate whether the choice of antivirals affects influenza burden.

PLAIN LANGUAGE SUMMARY

Previous studies have shown that antiviral drugs help prevent flu-related complications and lower healthcare utilization and costs. However, these previous studies have focused on working aged people with existing health problems. Our study looks at how antiviral treatment can lower the health and financial burden caused by the flu in older adults. Using a Medicare claims database from the 2016–2018 flu season, we identified 116,901 matched (treated versus untreated) patient pairs. All-cause mortality within 6 months from the index diagnosis (defined as the first claim with a flu diagnosis) was 1.6% among treated versus 4.3% among untreated patients. Rates (treated versus untreated) of all-cause inpatient hospitalizations during follow-up (defined as 6 months after the index diagnosis date) were 13.9% versus 22.7% and respiratory-related hospitalizations were 4.2% versus 9.0%. Mean total all-cause and respiratory-related costs were $9,830 and $900 among the treated, respectively, versus $13,207 and $2,024 among untreated, respectively. All differences were statistically significant (p < 0.001). This analysis of older adults with the flu found that prompt antiviral treatment is associated with lower rates of mortality and acute complications, reduced hospitalization, and lower healthcare costs. Use of antiviral treatment for patients at high risk of flu, such as older adults, is warranted.

Keywords:

• Medicare
• antivirals
• influenza
• hospitalization
• cost
• mortality
• treatment status
• matched analysis

JEL CLASSIFICATION CODES:

• I10
• I1
• I
• I00

Declaration of financial/other relationships

EC, and MHT are employees of PHAR (Partnership for Health Analytic Research), a health services research company paid to conduct the research described in this manuscript. At the time this study was conducted, SRR and KB were employees of PHAR. JB and AS are employees of Genentech, Inc., the study sponsor.

Author contributions

Concept and design (JB, SRR, EC, KB, AS); acquisition of subjects and/or data (SRR, EC, KB, MHT), data analysis (SRR, EC) and interpretation (JB, SRR, EC, KB, AS), and preparation of manuscript (SRR, JB, EC, KB, MHT, SC, AS).

Acknowledgements

No assistance in the preparation of this article is to be declared.

Availability of data and materials

The data that support the findings of this study originate from Medicare data, which are available from the Centers for Medicare and Medicaid through ResDAC (https://www.resdac.org/).

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This research was funded by Genentech, Inc. The sponsor provided input on the design and methods (protocol) and review of the manuscript (PHAR authors prepared the manuscript). The sponsor did not have a role in subject recruitment, data collections, or analysis.