PT  - JOURNAL ARTICLE
AU  - Joseph Jonathan Lee
AU  - Margaret Smith
AU  - Clare Bankhead
AU  - Rafael Perera Salazar
AU  - Antonis A. Kousoulis
AU  - Christopher C. Butler
AU  - Kay Wang
TI  - Oseltamivir and influenza-related complications in children: a retrospective cohort in primary care
AID  - 10.1183/13993003.02246-2019
DP  - 2020 Jan 01
TA  - European Respiratory Journal
PG  - 1902246
4099  - http://erj.ersjournals.com/content/early/2020/05/26/13993003.02246-2019.short
4100  - http://erj.ersjournals.com/content/early/2020/05/26/13993003.02246-2019.full
AB  - Background Influenza and influenza-like illness (ILI) place considerable burden on health care systems, especially during influenza epidemics and pandemics. During the 2009/10 H1N1 influenza pandemic, UK national guidelines recommended antiviral medications for patients presenting within 72 h of ILI onset. However, it is not clear whether antiviral treatment was associated with reductions in influenza-related complications.Methods Our study population consisted of a retrospective cohort of children aged 17 years or younger who presented with influenza/ILI at UK primary care practices contributing to the Clinical Practice Research Datalink during the 2009/10 pandemic. We used doubly robust inverse-probability weighted propensity scores and physician prior prescribing instrumental variable methods to estimate the causal effect of oseltamivir prescribing on influenza-related complications. Secondary outcomes were complications requiring intervention, pneumonia, pneumonia or hospitalisation, influenza-related hospitalisation and all-cause hospitalisation.Results We included 16 162 children of whom 4028 (24.9%) were prescribed oseltamivir, and 753 (4.7%) had recorded complications. Under propensity score analyses oseltamivir prescriptions were associated with reduced influenza-related complications (Risk Difference −0.015, 95% confidence interval [CI] −0.022 to −0.008), complications requiring further intervention, pneumonia, pneumonia or hospitalisation and influenza-related hospitalisation, but not all-cause hospitalisation. Adjusted instrumental variable analyses estimated reduced influenza-related complications (RD −0.032, 95%CI −0.051 to −0.013), pneumonia or hospitalisation, all cause and influenza-related hospitalisations.Conclusions Based on causal inference analyses of observational data, oseltamivir treatment in children with influenza/ILI was associated with a small but statistically significant reduction in influenza-related complications during an influenza pandemic.FootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Dr. Lee has nothing to disclose.Conflict of interest: Dr. Smith has nothing to disclose.Conflict of interest: Dr. Bankhead reports grants from NIHR School of Primary Care Health Sciences, during the conduct of the study.Conflict of interest: Rafael Perera SalazarConflict of interest: Dr. Kousoulis has nothing to disclose.Conflict of interest: Dr. Butler reports grants from NIHR, grants from EU Commission, personal fees from Roche Molecular Systems, grants from Roche Molecular Diagnostics, outside the submitted work.Conflict of interest: Dr. Wang reports grants from NIHR School for Primary Care Research, during the conduct of the study; and Kay Wang is funded by a NIHR Postdoctoral Fellowship.