We still don’t know whether neuraminidase inhibitors (e.g., oseltamivir [Tamiflu]) are helpful. Roche has prevented access to trial data until just this year, and the results of independent review are still pending. However, that has not stopped plenty of smart, well-meaning folks from taking their claims at face-value and using NAIs to treat influenza.
This is a retrospective registry review of 3 years of children admitted to California ICUs with a laboratory-confirmed diagnosis of influenza. 850 children were identified in the registry, and 784 children had clinical information available for analysis. Of these, 653 received NAIs and 38 (6%) died. Of the remaining 131 untreated patients, 11 (8%) died. Using a multivariate model adjusting for univariate predictors of death, NAI therapy was associated with decreased mortality (OR = 0.36, 95% CI 0.16-0.84).
But, while registry reporting was mandatory for deaths due to influenza, it was only optional for ICU hospitalization – leading to an unknown selection bias in their study cohort. There were also 23 deaths reported prior to hospitalization for whom no data is available. Most patients in the study treated with NAIs were H1N1, while the small remainder comes from the post-pandemic period with a mix of H1N1, other influenza As, and influenza B – and therefore may not be generalizable to a non-pandemic influenza season. A standardized abstraction form was used, but the complete baseline demographics collected are not included in the article; most patients included had significant respiratory comorbidities, and these chronically ill children were far more likely to die regardless of treatment. In summary, with a small sample size, likely missing data from abstraction, and selection bias underlying their cohort, the multivariate analysis upon which they based their final conclusion is junk.
In contrast to the editor’s summary “What this study adds”, which concludes special emphasis on treatment with NAIs may improve survival, I would revise it to say: “No additional practice-changing evidence”.
Now, I can’t say I’m opposed to treatment of hospitalized influenza patients with NAIs – least of all, those in the ICU. While outpatient therapy with NAIs for influenza is almost certainly a waste of money, in severe disease, the cost relative to the entire expenditure shrinks rapidly – the threshold for cost-effectiveness is met even if one patient out of a hundred has a one day reduction in ICU length-of-stay. But, it’s inappropriate to over-sell the meaning in this data to suggest any certainty NAIs are helpful.
“Neuraminidase Inhibitors for Critically Ill Children With Influenza”
http://www.ncbi.nlm.nih.gov/pubmed/24276847