When I first started to learn more about COVID19, I became extra concerned for my patients who smoke. The fulminant respiratory failure COVID causes is known as Acute Respiratory Distress Syndrome (ARDS), which carries a high mortality and can lead to a prolonged time on a ventilator. Carolyn Calfee and other scientists have demonstrated that tobacco increases a person’s risk of developing this severe syndrome, and I worried that would be the case here as well. Furthermore, smoking causes heart attacks, strokes, and other clotting disorders, and COVID19 also seems to make people more likely to form deadly clots as well.
There are some wonderful things happening now with science and preprint servers where non-peer-reviewed data is being released early to make science happen quickly. However, not going through peer review has led to some incomplete information being released to the public, resulting in potentially lethal misunderstanding. You may have read news articles (that I will not post here) talking about how it seems that there is a lower rate of smoking and vaping in people showing up to the hospital sick with COVID19. Experts think this is likely a misclassification error, which has a lot of plausibility for me. A misclassification error happens when people may not be getting their tobacco history assessed and therefore not being counted as smokers. COVID-19 serves as a perfect example. If you come in with rapidly progressive disease and are soon so sick you can’t talk and are on a ventilator, there’s no real way for me to ask you about your smoking history. This is especially true for the overwhelmed, high prevalence epicenter hospitals in which initial data was being collected (eg basis for the initial reports on “low smoking rates.”) Right now, when hospitals aren’t allowing visitors, I’m not going to be able to ask the family member who showed up with you whether you smoke. Furthermore, if you’re crashing onto life support and I’m spending all my time trying to keep you alive and get the ventilator adjusted, I honestly am not going to ask at that point about smoking. I always say it is very important to assess smoking history, even if you can’t talk to patients, but you can imagine in the middle of a surging pandemic with a busy ICU, it might get missed. Say you have 10 people who show up to the hospital, 5 who smoke and 5 who don’t. 1 of the smokers is only mildly sick, and can tell you they smoke. 4 of the smokers and 1 of the non-smokers either show up already on a ventilator in an ambulance or progress rapidly in front of your eyes and can’t talk to you. 4 of the non-smokers are also only mildly sick, and tell you they don’t smoke. Since you are only able to get a smoking history on one of the smokers, you rate the smoking prevalence as 1/10 when it is really 5/10. You also don’t pick up the very scary fact that 4/5 of your rapidly progressing and sick patients smoke.
Another factor may be age. Older patients have frequently stopped smoking and vaping, particularly if they have comorbidities, and it may be that age is just an outsized risk factor for having to go to the hospital that it does distort smoking numbers. Remember, these are numbers of people who reported to hospitals, not true COVID19 prevalence studies.
On a side note, I am not surprised that the author of one of the “low prevalence” studies Konstantinos Farsalinos has received funding from e-cigarette manufacturers, which is now disqualifying for membership in European Respiratory Society. Dr. Stan Glantz of the “corrupt or stupid” fame, has pointed this conflict out since 2014. Given Big Tobacco’s (and yes, the vaping industry is now Big Tobacco in new clothing) history of distorting and incompletely representing data, my suspicion is high here as well. But we will see, maybe it is true that there is some interesting scientific mechanism by which nicotine may lower the risk of contracting COVID19, but it would be fairly unprecedented, and there are plenty of reasons not to trust it. Furthermore, combustible tobacco likely kills around half of the regular users of its product, so I would not advise picking up a habit with a 50% mortality to avoid a 1% mortality (or wherever we find ultimate COVID19 mortality to land).
Furthermore, we have more science now. Well designed, peer-reviewed studies have shown that tobacco smoking is a risk factor for increased mortality from COVID19, and a recent meta-analysis (looking at multiple studies with over 11,000 patients) has shown that it is also a risk factor for more rapidly progressive disease. This is much more consistent with what we expect from our experience with tobacco in multiple other diseases and Acute Respiratory Distress Syndrome.
So what should you do with all this information? As always, don’t light things on fire and bring them into your lungs. In this case, don’t light tobacco on fire and breathe it in your lungs. If you need help to quit, reach out. Also consider donating to one of the great organizations fighting tobacco and helping people quit! Information on quitting and those organizations available on Resources page.
