Oseltamivir and influenza-related complications, hospitalization and healthcare expenditure in healthy adults and children

Abstract

Objective: To assess influenza-related secondary complications and healthcare use and costs in patients prescribed oseltamivir for influenza. Research design and methods: This study examined health insurance claims data for patients diagnosed with influenza during five influenza seasons. Patients prescribed oseltamivir were propensity matched with patients not prescribed antiviral therapy. Main outcome measures: Clinical outcomes were diagnosis with pneumonia, otitis media and hospitalizations, along with in-patient, out-patient and pharmacy use and costs. Results: Each group included 45,751 patients. Patients prescribed oseltamivir had significant reductions in the risks of pneumonia (odds ratio [OR]: 0.89, 95% CI: 0.80, 1.00), otitis media (OR: 0.84, 95% CI: 0.77, 0.91) and hospitalization (OR: 0.71, 95% CI: 0.62, 0.83). The risks of pneumonia and otitis media were also lower in children and adolescents (≤ 17 years) prescribed oseltamivir (OR: 0.74, 95% CI: 0.60, 0.91 and OR: 0.77, 95% CI: 0.69, 0.85, respectively). Total healthcare costs were lower for patients prescribed oseltamivir versus no antiviral therapy (mean US$500 versus 510; p < 0.0001). Patients prescribed oseltamivir had fewer claims per patient for antibiotics (0.37 versus 0.45; p < 0.0001), fewer physician visits (1.72 versus 1.78; p < 0.0001), emergency room visits (0.11 versus 0.12; p < 0.0001), and spent fewer days in hospital (0.04 versus 0.05; p < 0.0001). Conclusion: The risks of influenza-related complications and hospitalization, as well as healthcare use and costs, were lower for patients prescribed oseltamivir than for those with no antiviral prescription.

Keywords::

• hospitalization
• influenza
• oseltamivir
• otitis media
• pneumonia
• secondary complication

Acknowledgements

The authors would like to thank Daniel Smith for performing all programming and statistical analyses for this study, and Zoë Thornton-Jones, DPhil, Envision Pharma, Horsham, UK, for her editorial contributions to this manuscript. Abstracts describing some of the data included in this manuscript have been presented as posters at the American College of Emergency Physicians 2007 Scientific Assembly; 8 – 11 October 2007, Seattle, WA, USA and the American College of Clinical Pharmacists Annual Meeting 14 – 17 October 2007, Denver, CO, USA.

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