The last time the IDSA updated their influenza practice guidelines, it was the time of the 2009 H1N1 influenza pandemic. Fittingly, we are entering another season of H1N1 – and we have new guidelines, incorporating all the new evidence gathered in the meantime.
And, unfortunately, that is to say: we don’t really have any new, high-quality evidence.
The grading system for their recommendations includes two categories. Strength of recommendation:
- A: Good evidence to support a recommendation for or against use
- B: Moderate evidence to support a recommendation for or against use
- C: Poor evidence to support a recommendation
Quality of evidence:
- I: Evidence from 1 or more properly randomized controlled trials
- II: Evidence from 1 or more well-designed clinical trials, without randomization; from cohort or case-controlled analytic studies (preferably from >1 center); from multiple time-series; or from dramatic results from uncontrolled experiments
- III: Evidence from opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees
It would follow, then, for an “A” strength recommendation, this ought to reflect I or II quality of evidence – but a bizarrely staggering number of their recommendations are A-III, effectively self-contradicting. Most of their “Which Patients Should Be Tested for Influenza?” recommendations are A-III. The critical “Which Patients With Suspected or Confirmed Influenza Should Be Treated With Antivirals?” section features another batch of A-III recommendations, followed by several C-I and C-IIIs.
A long story short, this is simply paradoxical, making level A recommendations from class III evidence in the form of manufacturer sponsored trials, indirectly-sponsored meta-analyses, and observational data. Many authors of this piece are neck deep in reported financial and professional conflicts of interest with industry, which almost certainly eases any pain felt by distributing such internally invalid recommendations. After decades of controversy and hundreds of millions of dollars in profit for Genetech/Roche, we’re still bumbling along with our original momentum lacking a full understanding of the effectiveness and value of these medications.
“Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenza”
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciy866/5251935