Dobson J, Whitley RJ, Pocock S, Monto AS. Oseltamivir treatment for influenza in adults: a meta-analysis of randomised controlled trials. The Lancet. 2015;385(9979):1729-1737.

Clinical Question
Does oseltamivir significantly decrease symptoms in patients with influenza-like illness (ILI)?

Bottom Line
The use of oseltamivir is associated with an ~18-hour reduction in symptoms for patients with ILI (influenza confirmed). However, the use of oseltamivir comes at a cost due to the side effects of nausea and vomiting.

Study Design
-Study Type: Meta-analysis using patient-level data from 9 published and unpublished trials
-Population: 4328 patients who presented with ILI
-Intervention: Oseltamivir 75 mg BID x 5 days
-Control: Placebo
-Outcome: Time to alleviation of symptoms

Results

• 25-hour reduction in symptoms for patients with ILI and confirmed influenza (intention to treat infected population)
• 18-hour reduction in symptoms for patients with ILI and unconfirmed influenza
• Oseltamivir treatment increased the risk of nausea (RR 1.60) and vomiting (RR 2.43)

Strengths

• Included both published and unpublished RCT’s to overcome publication bias
• Included individual patient-level data instead of aggregated 
• Sub-group analyses performed including patients with influenza confirmed ILI

Criticisms

• Study indirectly sponsored by Roche
• Cochrane review found insufficient evidence regarding lower admission rates and respiratory tract complications
• The secondary outcome of respiratory tract infection is in question. The majority of this was bronchitis which is usually not treated with antibiotics. 
• Respiratory complications, not a pre-defined primary outcome and radiographic validation were not required

Further Discussion

• Are these results clinically meaningful? Does an 18-hour reduction in symptoms justify its use considering the risk of GI side effects?
• There is about a 1-day absolute reduction in the intention to treat the infected population (influenza confirmed). This raises questions about influenza testing, rapid testing availability, and its associated costs. Who do you test? If it takes 2 days for your test to come back, are you going to prescribe your patient oseltamivir before the results? Is there a clinical benefit of Tamiflu for patients who you don’t test?