This CoreIM podcast alerts us that we should use anti-viral influenza medications for patients who are at high risk of influenza infection. For a great resource on who needs treatment for influenza, see Influenza Antiviral Medications: Summary for Clinicians* from The Centers For Disease Control And Prevention:
[*This page has information on and links to the appropriate treatment of influenza.]
Page last reviewed: December 3, 2021
The information on this page should be considered current for the 2021-2022 influenza season for clinical practice regarding the use of influenza antiviral medications. Clinicians may also wish to consult the IDSA antiviral treatment and antiviral chemoprophylaxis recommendationsexternal icon, and the ATS-IDSA Adult CAP Guidelinesexternal icon.
This CoreIM podcast also has useful information in the use of Baysian statistics and the diagnostic odds ratio in medical decision-making. I’ll be making a post on the topic soon.
In this post I link to and excerpt from CoreIM‘s Mind The Gap podcast, Flu Diagnosis And Treatment. Posted: February 19, 2020
By: Dr. Steve Liu and Dr. Janine Knudsen
Graphic: Dr. Amy Ou
Audio: Dr. Steven R. Liu
Peer Review: Dr. Denise McCulloch, Dr. Jennifer Spicer
All that follows is from the above resource.
fig1 when available
- 03:33 The art of diagnosing the flu
- 05:20 Bayesian statistics and the diagnostic odds ratio
- 07:07 The ins and outs of diagnostic testing for the flu
- 08:40 Changes in influenza guidelines – testing and treatment
- 11:22 The not-so-rosy origin story of neuraminidase inhibitors (NAIs)
- 13:48 Neuraminidase inhibitors (NAIs), mortality benefit and limitations of studies
- 15:53 Take aways
- There are many influenza symptoms and most of them are not very helpful in confirming a case of the influenza. They have poor diagnostic odds ratios, which is defined as the ratio of the positive likelihood ratio over the negative likelihood ratio.
- To confirm a case, the IDSA recommends an influenza PCR
- PCR has a diagnostic odds ratio of ~100, whereas the antigen test (rapid influenza detection test) has a lower diagnostic odds ratio of 25.
- The influenza PCR can still have false positives. As with any test, apply the test to your pre-test probability – a number you come up with based on your local context – to get your post-test probability – the chance a patient truly has disease.
- The new 2018 influenza guidelines recommend:
- Treat any inpatient with suspected influenza, even without a confirmatory test, and even after they’ve had symptoms for 48 hours.
- Consider testing outpatients if it will change management.
- Consider treating outpatients who are likely to suffer complications from the flu, even without a confirmatory test
- Neuraminidase inhibitors, such as oseltamivir and zanamavir, were originally thought to decrease symptoms by 24 hours, and reduce complications and hospitalizations
- But in a big pharmaceutical scandal, previously unseen data was revealed and analyzed by the Cochrane Group, it showed these results were not completely accurate or as convincing as originally thought.
- Data from the 2009 influenza pandemic, when neuraminidase inhibitors were used broadly, generated new data which actually suggested a mortality benefit
- However, this data comes from observational studies, rather than randomized control trials, so may be subject to bias.
- Ultimately, neuraminidase inhibitors are the best and only option we currently have to treat the flu. This is why, despite their known side effects and questionable outcomes, IDSA guidelines have changed to recommend using them more broadly.