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Is there any better layman-readable source of medical news than StatNews?
Is there any better layman-readable source of medical news than StatNews?
www.statnews.com To avoid being redundant in this post I searched AB for StatNews posts and found only one quotation and linkage by member Reznik. I recommend members browse there. http://www.statnews.com

Coincidentally,  while browsing last night I followed a link to the page Reznik linked to at https://www.statnews.com/2020/04/08/doct...-covid-19/. The unusual breadth, depth and timeliness of that piece by Sharon Begley amazed me. (It  is about doctors seeing ventilator overuse). There are many many excellent articles there including others by Begley. Her current piece presents peer level critiques of methods and policy uses of the IHME Covid-19 model here https://www.statnews.com/2020/04/17/infl...itics-say/ .

I recommend reading both pieces, but here are some unattributed shippets from each piece (with my emphases and a couple of bracketed insertions):


-In a small study last week in Annals of Intensive Care, physicians who treated Covid-19 patients at two hospitals in China found that the majority of patients needed no more than a nasal cannula. Among the 41% who needed more intense breathing support, none was put on a ventilator right away. Instead, they were given noninvasive devices such as BiPAP; their blood oxygen levels “significantly improved” after an hour or two. (Eventually two of seven needed to be intubated.) The researchers concluded that the more comfortable nasal cannula is just as good as BiPAP and that a middle ground is as safe for Covid-19 patients as quicker use of a ventilator.

-High levels of force and oxygen levels, both in quest of restoring oxygen saturation levels to normal, can injure the lungs. “I would do everything in my power to avoid intubating patients,” Weingart said.

-One reason Covid-19 patients can have near-hypoxic levels of blood oxygen without the usual gasping and other signs of impairment is that their blood levels of carbon dioxide, which diffuses into air in the lungs and is then exhaled, remain low. That suggests the lungs are still accomplishing the critical job of removing carbon dioxide even if they’re struggling to absorb oxygen. That, too, is reminiscent of altitude sickness more than pneumonia.

The noninvasive [BiPaP is usually mentioned] devices “can provide some amount of support for breathing and oxygenation, without needing a ventilator,” said ICU physician and pulmonologist Lakshman Swamy of Boston Medical Center.
One problem, though, is that CPAP and other positive-pressure machines pose a risk to health care workers, he said.  The devices push aerosolized virus particles into the air, where anyone entering the patient’s room can inhale them. The intubation required for mechanical ventilators can also aerosolize virus particles, but the machine is a contained system after that.


“It’s not a model that most of us in the infectious disease epidemiology field think is well suited” to projecting Covid-19 deaths, epidemiologist Marc Lipsitch of the Harvard T.H. Chan School of Public Health told reporters this week, referring to projections by the Institute for Health Metrics and Evaluation at the University of Washington.

Others experts, including some colleagues of the model-makers, are even harsher. “That the IHME model keeps changing is evidence of its lack of reliability as a predictive tool,” said epidemiologist Ruth Etzioni of the Fred Hutchinson Cancer Center, who has served on a search committee for IHME. “That it is being used for policy decisions and its results interpreted wrongly is a travesty unfolding before our eyes.”

The IHME projections were used by the Trump administration in developing national guidelines to mitigate the outbreak. Now, they are reportedly influencing White House thinking on how and when to “re-open” the country, as President Trump announced a blueprint for on Thursday.

The chief reason the IHME projections worry some experts, Etzioni said, is that “the fact that they overshot” — initially projecting up to 240,000 U.S. deaths, compared with fewer than 70,000 now — “will be used to suggest that the government response prevented an even greater catastrophe, when in fact the predictions were shaky in the first place.

------------------------DEEPER INTO MORE DETAIL

There are two tried-and-true ways to model an epidemic. The most established, dating back a century, calculates how many people are susceptible to a virus (in the case of the new coronavirus, everyone), how many become exposed, how many of those become infected, and how many recover and therefore have immunity (at least for a while). Such “SEIR” models then use what researchers know about a virus’s behavior, such as how easily it spreads and how long it takes for symptoms of infection to appear, to calculate how long it takes for people to move from susceptible to infected to recovered (or dead).

Newer, “agent-based models” are like the video game SimCity, but with a rampaging pathogen: using computing power unimagined even a decade ago, they simulate the interactions of millions of individuals as they work, play, travel, and otherwise go about their lives. Both of these approaches have often nailed projections of, for instance, U.S. cases of seasonal flu.

IHME uses neither a SEIR nor an agent-based approach. It doesn’t even try to model the transmission of disease, or the incubation period, or other features of Covid-19, as SEIR and agent-based models at Imperial College London and others do. It doesn’t try to account for how many infected people interact with how many others, how many additional cases each earlier case causes, or other facts of disease transmission that have been the foundation of epidemiology models for decades.

According to a critique by researchers at the London School of Hygiene & Tropical Medicine and Imperial College London, published this week in Annals of Internal Medicine, the IHME projections are based “on a statistical model with no epidemiologic basis.”

“Statistical model” [as mis-applied to IHME model (2SB)] refers to putting U.S. data onto the graph of other countries’ Covid-19 deaths over time under the assumption that the U.S. epidemic will mimic that in those countries. But countries’ countermeasures differ significantly. As the epidemic curve in the U.S. changes due to countermeasures that were weaker or later than, say, China’s, the IHME modelers adjust the curve to match the new reality.

“This appearance of certainty is seductive when the world is desperate to know what lies ahead,” Britta Jewell of Imperial College and her colleagues wrote in their Annals paper. But the IHME model “rests on the likely incorrect assumption that effects of social distancing policies are the same everywhere.” Because U.S. policies are looser than those elsewhere, largely due to inconsistency between states, U.S. deaths could remain at higher levels longer than they did in China, in particular.

While other epidemiologists disagree on whether IHME’s deaths projections are too high or too low, there is consensus that their volatility has confused policy makers and the public:
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RE: Is there any better layman-readable source of medical news than StatNews?
ScienceDaily under the health tab.
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