3 ms·

> Studies coming out that people who survived severe covid had over twice the risk of dying within the next year. I'm curious how those studies would disentang

> Studies coming out that people who survived severe covid had over twice the risk of dying within the next year. I'm curious how those studies would disentangle the effect of "COVID damages your health, and severe COVID damages your health more so you're more likely to die in the next year" from the effect of "if you are in worse general health, a COVID infection is more likely to be severe, and also you are more likely to die in the next year". Even if you try to control for factors like age, sex, smoker vs nonsmoker, BMI, etc etc you're likely to miss something. But maybe they did something clever with their control group that serves as a good proxy for "people who would have had severe covid and survived, but didn't get infected". I'm interested to see which study you're referring to.

boringg 5y ago
Agree there are disentangling challenges. However if you think about it logically from a health perspective - if your respiratory system goes under severe stress that will likely exacerbate any respiratory issues that were in your system beforehand. It is surprising that the risk is so great for the following year, but not shocking considering how taxing this disease is on peoples health. https://www.cidrap.umn.edu/news-perspective/2021/12/severe-covid-tied-high-risk-death-mostly-other-causes-within-year https://www.cidrap.umn.edu/news-perspective/2021/12/severe-c...
- JoshuaDavid 5y ago
  Hm, I think that article references this paper[1]. It looks like their "control group" was patients who were tested for COVID-19 for any reason. They then checked whether the age distributions and distributions of Charleson Comorbidity Scores were the same for people who tested positive vs those who tested negative (of positive tests, 65.3% were under 65 vs 64.5% of negative tests, 53.5% had a comorbidity score of 0 or 1 among positives vs 49.4% among negatives). However, they then checked the age distributions between mild and severe cases, found very large differences (54.5% of severe cases were over age 65 vs 20.3% of mild cases, and 74.2% of severe cases had a comorbidity score of 2 or more vs 26.4% of mild cases)[2]. And then if I'm reading correctly, they just decided that was fine and they'd calculate the hazard ratios for mild vs severe COVID without adjusting for underlying confounders anyway? Their methodology doesn't look super sketchy when it comes to COVID vs no COVID, but I am not sure what they're trying to do by comparing mild with severe COVID without even controlling for counfounding factors. [1] https://www.frontiersin.org/articles/10.3389/fmed.2021.778434/full https://www.frontiersin.org/articles/10.3389/fmed.2021.77843... [2] https://www.frontiersin.org/files/Articles/778434/fmed-08-778434-HTML-r1/image_m/fmed-08-778434-t002.jpg https://www.frontiersin.org/files/Articles/778434/fmed-08-77...

boringg 5y ago

Agree there are disentangling challenges. However if you think about it logically from a health perspective - if your respiratory system goes under severe stress that will likely exacerbate any respiratory issues that were in your system beforehand. It is surprising that the risk is so great for the following year, but not shocking considering how taxing this disease is on peoples health. https://www.cidrap.umn.edu/news-perspective/2021/12/severe-covid-tied-high-risk-death-mostly-other-causes-within-year https://www.cidrap.umn.edu/news-perspective/2021/12/severe-c...

JoshuaDavid 5y ago
Hm, I think that article references this paper[1]. It looks like their "control group" was patients who were tested for COVID-19 for any reason. They then checked whether the age distributions and distributions of Charleson Comorbidity Scores were the same for people who tested positive vs those who tested negative (of positive tests, 65.3% were under 65 vs 64.5% of negative tests, 53.5% had a comorbidity score of 0 or 1 among positives vs 49.4% among negatives). However, they then checked the age distributions between mild and severe cases, found very large differences (54.5% of severe cases were over age 65 vs 20.3% of mild cases, and 74.2% of severe cases had a comorbidity score of 2 or more vs 26.4% of mild cases)[2]. And then if I'm reading correctly, they just decided that was fine and they'd calculate the hazard ratios for mild vs severe COVID without adjusting for underlying confounders anyway? Their methodology doesn't look super sketchy when it comes to COVID vs no COVID, but I am not sure what they're trying to do by comparing mild with severe COVID without even controlling for counfounding factors. [1] https://www.frontiersin.org/articles/10.3389/fmed.2021.778434/full https://www.frontiersin.org/articles/10.3389/fmed.2021.77843... [2] https://www.frontiersin.org/files/Articles/778434/fmed-08-778434-HTML-r1/image_m/fmed-08-778434-t002.jpg https://www.frontiersin.org/files/Articles/778434/fmed-08-77...