We cannot assume those that die from Covid are "least healthy" within their risk group. — boethius

It isn't necessary that those within a risk group that are "least healthy" will die, it's just more likely. If you found any factor or variable which contributed to risk, and it wasn't aliased with the risk group already, those in the sub group of that risk group that have the extra risk are more likely to die than those in the base risk group. If you condition on death, you're already pre-selecting for demography and other characteristics which make death more likely; as in, within the group of those who have died from COVID (or any other thing), the characteristics that make death more likely will be more prevalent than they are in the general population (on average). It's the same mechanism that makes the more severe cases of COVID be more likely to be tested for COVID, but in a different form.

To be super clear about this; if your sample is those who have died while having COVID, that sample is more likely to contain a higher number of people on average who fall into the groups that amplify risk. Like... those who have died from COVID are more likely to have comorbidities and be older.

It isn't necessary that those within a risk group that at "least healthy" will die, it's just more likely. If you found any factor or variable which contributed to risk, and it wasn't aliased with * the risk group already, those in the sub group of that risk group that have the extra risk are more likely to die. — fdrake

This is simply not true, as I've explained above.

First of all, at this stage with a small percentage of the population that has gotten Covid, it just doesn't matter because 90-99% of these "least healthy" are still out there and will continue to die due to whatever they are at risk of.

Second of all, even of the people that die within a risk group, the factors determining death compared to one's peers could be otherwise benign. A particularly unhealthy smoker may survive Covid due to some completely benign genetic difference, such as exact shape of proteins on cells etc.

An example, it seems blood type O is particularly resistant to Covid, but blood type O does not provide a similar resistance to smoking. So O blood type's who smoke and survive Covid due to this genetic advantage, there's no reason to assume that they were a "particularly healthy" smoker.

It's an over simplistic assumption to postulate Covid deaths is selecting for "least healthy" within a risk group. It seems intuitively correct, but is not correct.

As I've also mentioned previously, the survivors of Covid, but with long term lung damage or treatment complications, may then replenish the "least healthy" category even if there was such a selector for "least healthy" to begin with.

Good to hear, I live 20 miles south west of Norfolk England. We bought a house where you can buy property with land at a reasonable price, we are surrounded by farmland. But the peace and quiet is worth it. There are a few redneck farms around, I get on ok with them though, a small price to pay.

Sorry to hear how the authorities treat you in Moscow. Aren't you allowed to go out to exercise? Don't worry about the mess, my house would be messy if my wife didn't make me remind me to tidy up and do the housework regularly.

I'm near Diss, West Anglia isn't talked about, it's called the fens in these parts, I couldn't live there.

No it can't, if you're trying to support the idea that Covid kills the "particularly unhealthy". Lot's of "particularly unhealthy" simply don't get the disease, so there will remain lot's of these "particularly unhealthy" around since they didn't get infected. — boethius

I'm not suggesting none of the "particularly unhealthy" will remain. Only that they constitue both the cohort from which Covid-19 draws most of its fatalities and also the group from which the general death rate draws most of it's fatalities.

Being the same group means that if one draw reduces the numbers, the other will have proportionately fewer to draw from.

I'm saying there's no reason to assume the variation of death and survival within a risk group is due to being "particularly unhealthy" within that group. It could be some other mechanism such as otherwise benign genetic differences, or then simply random variation such as where exactly the virus begins replicating in the body, that then dominates chances of death within a risk group. — boethius

Well then support that theory with evidence from the literature. Otherwise it's just idle speculation and you're using it to fuel serious fear and panic so it had better be damn good evidence.

It's an over simplistic assumption to postulate Covid deaths is selecting for "least healthy" within a risk group. It seems intuitively correct, but is not correct. — boethius

It selects for COVID-19 resistant. Still, a COPD patient who has it has a poor prognosis.

Aren't you allowed to go out to exercise? — Punshhh

Since March 30, officially no:

According to the published decree, leaving one’s place of residence is permitted only for the following: seeking emergency medical care or other direct threats to life and health; traveling to and from work if required to do so; shopping at the nearest existing store or pharmacy; walking pets at a distance not to exceed 100 meters from one’s residence; taking out household garbage. — US embassy

But so far it's not as strict as Spain. Unlike there, I haven't encountered any police checking what I buy at the supermarket. In fact I haven't seen any police in this neighbourhood at all.

Don't worry about the mess, my house would be messy if my wife didn't make me remind me to tidy up and do the housework regularly — Punshhh

Unfortunately my wife is as bad as me.

Tomorrow, I'll definitely do it tomorrow.

It's an over simplistic assumption to postulate Covid deaths is selecting for "least healthy" within a risk group. It seems intuitively correct, but is not correct. — boethius

Whether it's a random sample with no causal mechanism or not depends on the model. Some models are better.

The question is: who are those people who are most likely to die of COVID? That's people who are elderly and have comorbidities.

If the question is: how many deaths are attributable to COVID? That's a bit different. If the question is restricted to: how many deaths of those in a given comorbidity + age risk group are attributable to COVID? It revolves around the counterfactual: If you gave someone with those characteristics COVID, how much more likely are they to die than if they did not have COVID? This is much harder to answer, requires an explicit model of how COVID interacts with the comorbidities, and can't be immediately read off the risk of death of those people who have those characteristics (comorbidity + age) who have confirmed cases and died in hospital (that group selects for comorbidity severity already!)

Edit: if you have a link to a study which is doing this kind of calculation, or something similar, already (trying to quantify EXTRA deaths from covid within risk categories), I'd like to see it!

Some “seroprevalence” studies are beginning to come out. This one is not peer-reviewed, but it’s conclusions are profound.

Under the three scenarios for test performance characteristics, the population prevalence of COVID-19 in Santa Clara ranged from 2.49% (95CI 1.80-3.17%) to 4.16% (2.58-5.70%). These prevalence estimates represent a range between 48,000 and 81,000 people infected in Santa Clara County by early April, 50-85-fold more than the number of confirmed cases. Conclusions The population prevalence of SARS-CoV-2 antibodies in Santa Clara County implies that the infection is much more widespread than indicated by the number of confirmed cases.

https://www.medrxiv.org/content/10.1101/2020.04.14.20062463v1

An example, it seems blood type O is particularly resistant to Covid, but blood type O does not provide a similar resistance to smoking — boethius

This is trivial compared to the disproportionate risk having heart disease, lung conditions or undergoing treatment for cancer has on your risk from dying of Covid-19. Those are overwhelmingly the main risk factors. They are also overwhelmingly the main risk factors for death in general. Minor variations in genetic make up (which do not also affect things like infection, heart disease and cancer) are just that... Minor.

This is trivial compared to the disproportionate risk having heart disease, lung conditions or undergoing treatment for cancer has on your risk from dying of Covid-19. — Isaac

But these are the large groups I've been talking about.

Yes, heart disease is a big predictor of Covid outcome, but it's a large group and there's simply no reason to assume deaths from Covid overlap with some unknown "particularly unhealthy" sub-group of heart disease.

There are definitely known subgroups such as those already experience heart failure, or have had a heart transplant which is being rejected, which I would assume Covid is an even bigger risk. But there is no evidence that Covid is only affecting this known extreme risk subgroup.

Your argument is that we can assume Covid selects for the "particularly unhealthy" within these groups, but there is no reason to assume that is the case. We cannot expect heart attacks to lesson substantially after Covid because the "particular bad cases of heart disease" were culled from the heart disease risk group.

Now, maybe heart attacks do decrease due to systemic effects such as people de-stressing in lockdown, but this is totally different than a "cull effect".

And, even if there was a substantial cull effect, many survivors may have long term injury that simply replenishes the "particularly unhealthy" end of their risk group.

The question is: who are those people who are most likely to die of COVID? That's people who are elderly and have comorbidities. — fdrake

I'm not disagreeing that people with comobidities are more likely to die from Covid.

My argument is a counter-argument to the idea that Covid is shaving off a population from these risk groups that can be in some sense said to "about to die anyways"; I've been using a year as a baseline time frame for the meaning of "about to die".

Covid doesn't kill enough people to have an obvious and noticeable statistical effect of this kind, such as non-respiratory disease going forward making up for, or nearly making up for, Covid deaths and arriving at some equilibrium.

If Covid killed everyone who smoked, everyone with heart disease, and every cancer patient and all the old people, then it would have such a very noticeable effect, but the disease doesn't behave in this way and we cannot assume that "particularly unhealthy anyways" dominates in determining who in these risk groups actually dies from Covid; other factors could dominate the death selection process within these groups.

Now, maybe this effect of less respiratory disease deaths does actually happen, since the lockdowns we can easily expect to have a significant change to peoples relationship to pollution, to stress, and to influenza and other infections -- that we can assume are also depressed by the lockdowns. But these effects are due to the lockdowns, not due to Covid culling the "otherwise would have died anyway" group in a big way.

there's simply no reason to assume deaths from Covid overlap with some unknown "particularly unhealthy" sub-group of heart disease. — boethius

Firstly, yes there is a reason. Those most likely to die in the "heart disease" group are those with the weakest hearts (for various reasons), those are the same people who, within that group, are more likely to die from Covid-19. It is the inability of the heart to support recovery which causes the fatality, not some dice-rolling random factor. The exact same factor.

Secondly, even if the studies relating heart disease to Covid-19 deaths turned out to be wrong about the mechanism, there are still no studies showing the opposite (as you are claiming) a lack of overlap in mechanism.

As I said, if you're going to spread hysteria, you'd better have damn good evidence backing it up, not a bit of guesswork and a lack of contrary evidence.

Those most likely to die in the "heart disease" group are those with the weakest hearts (for various reasons), those are the same people who, within that group, are more likely to die from Covid-19. It is the inability of the heart to support recovery which causes the fatality, not some dice-rolling random factor. The exact same factor. — Isaac

No, this simply isn't true. You are taking a truism too far.

Also, note that you also have to deal with the fact that right now it's a small group of people who have been infected, and so the effect you describe would not be noticeable much anyways simply because the vast majority of "those with the weakest heart" have not yet gotten the disease. And even if you deal with that, you still have to deal with the fact that long term lung injury or treatment complications may simply replenish this supply of "those with the weakest heart".

However, even the middle part of assuming Covid kills "those with the weakest heart" within the heart disease group is not a sound argument. Other factors can easily dominate in selecting for death within the heart disease group.

Furthermore, a big determining factor for surviving a heart attack is time and place, and this is a completely independent variable to Covid; likewise, people may improve or deteriorate their lifestyle moving from this "weakest" category to "ok" or vice versa, or a really stressful life event has an acute impact on heart disease likelihood; failing to seek timely treatment etc.

Point being, even simply considering these future events that determine heart disease deaths, in other words make your "weakest heart" category not static but a dynamically changing group, significantly enlarges the category of "weakest heart"; i.e. Covid may kill someone who is in the "weakest" category now, but would otherwise have gone on to make life changing decisions and moved out of the weakest category, and so would not have appeared as a heart disease death in the short term.

So, you also have to deal with the dynamic nature of your "weakest" category, in addition to deal with the fact "weakest" is not a given and other factors may dominate who dies and who doesn't of Covid with a risk category. After solving these, there is the fact not enough people have gotten Covid for such an effect to be large, and the fact that if that does happen, Covid does kill off the "weakest", that those that survive may now have long term comorbidity effects due to Covid, thus replenishing this "weakest" group.

The exact same factor. — Isaac

Yes, there is the same factor.

But having a factor of risk does not mean you will die within a short period of time, it is just a factor.

You are making a completely unfounded addition to the risk group observation that Covid somehow selects to the weakest members of those risk groups -- essentially the terminally ill but we don't know it. There's no reason to assume such a thing. If Covid was a disease of the terminally ill, such as a hospital disease that kills only those with essentially failed immune systems, we would know it by now. There's no reason to assume that there's some hidden group of "true terminally ill people" that make up "actual expected deaths within a year" that we don't know about but will discover because Covid kills them and then they do not live to be killed of their other risk factor. Furthermore, I don't think any doctor would agree such a "hidden terminally ill" group exists, but would say there's a large element of chance within these large risk groups, such as heart disease or smoking or cancer.

Therefore, the only way to have a culling effect is if a disease killed a large proportion of such people, otherwise, with a small amount of killing that Covid does, small in the sense of seeing such an overlap between "Covid deaths" and "people who are about to die anyways", the same "elements of chance" continue to operate in determining who has a turn for the worse, who responds well to treatment and who doesn't, who encounters deteriorating life conditions, develops an addictions, has an accident or some other complicating factor, with respect to Covid as well as whatever other conditions such people continue to have.

In other words, there is not some well ordered spectrum from "good to worse" of heart disease, or lung disease, and that people simply move progressively towards "worse" and then fall off the edge and die. There is a large element of intrinsic randomness and re-ordering due to contingent events, which is why these groups are large and not already separated in a finely grained way with excellent predictors of who in particular is going to die in a given time frame. It's an extremely small group of people who doctors are "certain" will die in any relatively short time frame, such as a year.

Just wait 3 more days and look at the official figures:

https://www.ons.gov.uk/file?uri=%2fpeoplepopulationandcommunity%2fbirthsdeathsandmarriages%2fdeaths%2fdatasets%2fweeklyprovisionalfiguresondeathsregisteredinenglandandwales%2f2020/referencetablesweek142020.xlsx

The last official figures show that there were 6000 deaths registered above average. That is around 50% above average so hard to ignore without a damn good explanation.

requires an explicit model of how COVID interacts with the comorbidities, and can't be immediately read off the risk of death of those people who have those characteristics (comorbidity + age) who have confirmed cases and died in hospital (that group selects for comorbidity severity already!) — fdrake

Yes, this is my point. If the comorbidity groups are large, we can't simply assume Covid is killing off some unknown sub-group who are very likely to die in some agreed short term anyway; and once such comorbidity groups are large it is implausible such a subgroup even exists that explains many, much less all, deaths in that group: Some people in the risk group die due to simply being in the risk group, without some hidden mechanism that explains why they in particular died, and even if there are hidden subgroups there's no reason to expect they overlap with the subgroup of people more likely to die of Covid -- some otherwise benign genetic difference may dominate here, exactly why species store up diversity in case some otherwise benign difference is no longer benign given new conditions.

If you take out the entire risk group, then it's a different story, but Covid is not remotely lethal enough; therefore, there's no reason to expect Covid deaths intersect with "would die anyways from underlying conditions in the short term". In a refutable form; Covid discovering for us there are such hidden "weakest, about to die" subgroups in otherwise large risk-groups with little success so far in a finer grained differentiation, would be the greatest medical discovery of all time.

@Hanover
For some reason the models say your state's peak deaths is two week away while my state's is already passed.

But they're going to open Texas! Woo hoo!

we can't simply assume Covid is killing off some unknown sub-group who are very likely to die; — boethius

I mean, COVID is more likely to kill people who are more likely to die anyway. This complicates whatever attribution of death to COVID you do.

Even if the infection risk is constant across the factors that increase the likelihood of death. If COVID infection initiates the causal chain that leads to their death, even if it's the knock on effects (like it interacting with comorbidities) that ultimately kill people, that's going to make the number of deaths attributable to COVID much higher than it would otherwise be - IE, if COVID's the thing that's making people in the underlying risk groups die, and they wouldn't've died now without COVID, then it's COVID's fault they died now.

It can still be that COVID infection is what killed them, even if the majority of people end up dying from heart failure or kidney failure, or other complications (rooted in comorbidity or not).

If I were you I’d be saying ‘Oh no!’

I mean, COVID is more likely to kill people who are more likely to die anyway. This complicates whatever attribution of death to COVID you do. — fdrake

I don't disagree here. Where I disagree is this effect will be big in terms of reducing deaths from these risk factors going forward.

The original claim I have contention with, is that respiratory deaths may go so low after Covid as to balance Covid deaths. So a incredibly large effect.

There is definitely some overlap, but my contention is it is small; small in the sense that it could be completely ignored in calculating likely deaths in these risk groups (though there can be other causes of big changes, such as the lock-downs). I.e. if you calculate the people who die of Covid that are at risk of heart disease in likely scenario of your choosing, and then calculate the people who will die of heart disease, you can essentially ignore the the fact some people died of Covid in this category other than there simply being slightly less people. That there is not a big culling effect.

It's not big now because most people haven't gotten the disease yet.

It may never be a big effect because likely Covid simply doesn't kill those who are about to die in the short term. I've defined short term as a year and explained all the reasons why we wouldn't expect there to be an overlap with "people who would otherwise die this year" and there's no reason to assume such a category even exists now in a predictive sense.

It may be an effect that that is not only not big but is dominated by something that goes in the other direction, such as a large amount of long term lung injury that replenishes the at risk categories, or even increases them.

I were you I’d be saying ‘Oh no!’ — I like sushi

I always alternate woo hoo' s and oh no's.

Woohoos and d'ohs for me.

:razz:

The original claim I have contention with, is that respiratory deaths may go so low after Covid as to balance Covid deaths. — boethius

If COVID kills the majority of people that would've otherwise died from these issues (pulmonary, heart, cancer patients). and there isn't a corresponding increase of intake in those risk groups over the relevant time period, the number of people that could die from those issues after this year (in the relevant short time period) is going to be lower. It isn't so much that this will cancel out the deaths attributable to COVID, it's that it'll constrain the number of people that could die from other causes in that group (irrelevant of what they are); since the dead people won't be in that group any more, and certainly can't die from other causes if they're already dead from COVID. (@Isaac 's use of the word "cohort" in his responses probably is used to emphasise this time moving property when fixing a group to study over time, cohorts have a fixed initial size that depletes through death/over time)

Other factors can easily dominate in selecting for death within the heart disease group. — boethius

What are these factors then (presumably ones which don't also overlap with factors making death from Covid-19 more likely)?

Furthermore, a big determining factor for surviving a heart attack is time and place, and this is a completely independent variable to Covid — boethius

Really? In what way? Presumably proximity to medical services is the key variable in time and place (those more remote will have more difficulty). How is that different with Covid-19?

people may improve or deteriorate their lifestyle moving from this "weakest" category to "ok" or vice versa, or a really stressful life event has an acute impact on heart disease likelihood; failing to seek timely treatment etc. — boethius

Again, how do these categories differ from those which relate to vulnerability to Covid-19 fatality? Stress, for example, suppresses immune response.

For some reason the models say your state's peak deaths is two week away while my state's is already passed.

But they're going to open Texas! Woo hoo! — frank

I don't know what we'll do here. Georgia's governor is really pretty stupid. You'd think from the governors we elect that we really talk this slow.


I do like the dancing guy with the beard in the back left. Not sure what he's listening to, but he's way into it.

Fox is reporting that it was a research project that escaped from a Wuhan lab...

The last official figures show that there were 6000 deaths registered above average. That is around 50% above average so hard to ignore without a damn good explanation. — I like sushi

Have you seen people ignoring it? Last time I looked the world was practically hysterical about it. There's certainly a considerable disagreement as to how best to proceed, but I think everybody's way beyond ignoring it.