Thread by @montastrucf

1/ After #hydroxychloroquine #fluvoxamine, #paxlovid = #evusheld !
The pandemic of immortal time bias continues...
@drjohnm @venkmurthy @VPrasadMDMPH @TracyBethHoeg

https://twitter.com/montastrucf/status/1624527828736696322

2/Today we publish in @CIDJournal a letter on a new observational study of the covid-19 antibody tixagevimab/cilgavimab #Evusheld
👇
academic.oup.com/cid/advance-ar…
@VPrasadMDMPH

3/ The cohort study reporting an decrease risk of myocardial infarction, arrhythmia or heart failure in the 30 days after treatment by tixagevimab/cilgavimab compared to the control cohort (relative risk : 0.84, 0.93, 0.89)

4/ The results are surprising since they suggest protective effects of treatment with tixagevimab/cilgavimab compared with a group of patients unexposed and with lower cardiovascular risk at baseline.

5/ The results are in contrast with two recent studies suggesting an increased risk of serious cardiovascular events after tixagevimab/cilgavimab treatment.

6/ The first one (by @JolantaPiszcze2) was a meta-analysis of published and unpublished RCTs showing an increased odds of cardiac and vascular serious adverse events in tixagevimab–cilgavimab-treated patients (OR 1.90, 95%CI 1.05,3.43)
👉sciencedirect.com/science/articl…

7/ The second one (our pharmacovigilance study) found that compared with other anti-SARS-CoV-2 mAbs, the use of tixagevimab/cilgavimab was associated with an increased risk of reporting arterial thromboembolic events (OR 3.25; 95%CI 1.73,6.10)

👉sciencedirect.com/science/articl…

8/ To explain discrepancies between the latest studies and the cohort study, we believe that the study is subject to immortal time bias, which can generate an illusion of protective effect

👉explanation in our paper academic.oup.com/cid/advance-ar…

9/ ...and this pandemic does not stop at risk assessment, but also affects benefit assessment.
For example, another study assessing the "beneficial" effect of #evusheld on the risk of COVID-19 infection in transplant patients
@amjtransplant
pubmed.ncbi.nlm.nih.gov/36695703/

10/ in practice, pharmaco-epidemiological studies are a good complement to clinical trials but only with a good method to avoid, in particular, the immortal time bias that we have so often denounced for observationnal studies with hydroxychloroquine, fluvoxamine, invermectine....

11/ finally, we are still waiting for a robust clinical trial to demonstrate the clinical benefit of tixagevimab/cilgavimab #evusheld against covid-19 version 2022 (omicron variants), because as we have shown there are serious cardiovascular risks with this drug

12/ and the pandemic of immortal time bias is not only affecting the field of "covid-19" drugs, see also in cardiology, this article published in another "top journal". @CircAHA
ahajournals.org/doi/10.1161/CI…
👉with the explanation by @drjohnm sensiblemed.substack.com/p/a-flawed-ana… @AtulPathak31

13/ To understand, you could read the article by the McGill Pharmacoepi team @AmJEpi
"Biases in Evaluating the Safety and Effectiveness of Drugs for the Treatment of COVID-19: Designing Real-World Evidence Studies"
academic.oup.com/aje/article/19…