Please note:<p>The calculation of TyG is ln (fasting blood sugar) x triglycerides/2). Many studies make the error of calculating it as (ln (FBS x TG))/2. The only online calculator I've found, I think, falls into the latter category, or has worse errors - I didn't go through it too rigorously, but I put in values beyond what human life can sustain and didn't get close to the cut-off for this paper's bottom risk tier.<p>If you look at studies/calculator using the latter calculation, it looks like this study looks at <i>really, really</i> severe diabetics.<p>If you compare with the appropriate calculation, though, they're looking at more run-of-the-mill "not optimally treated and obese" diabetics.<p>Hosseini 2017 did a paper analyzing a number of other TyG papers and calculating results under both calculation methodologies, for context.<p>Please also note that this paper does not state <i>when</i> the results were collected. Insulin resistance/hyperglycemia is a symptom of sepsis - if these labs were drawn on already-severe patients, it would be entirely unclear whether they reflect a cause or an effect (or, as is almost certainly the case, both!).
Covid-19 is a very strange disease, it seems like it is amplified either way (severe vs. non-severe) depending on health. This seems different from the flu as the flu hits everyone very hard, the elderly/sickly especially hard. With covid some people who have it, do not and will not have any symptoms which cannot be said for the flu. I feel like the insulin marker data is an albatross, having high TyG means alot of systems in your body are not doing well, and the virus attacks weakness, it(covid-19) is also found to produce extreme clotting so that is probably why people with diabetes/heart disease and hypertension are all at high risk.
I've suspected for a long time that Insulin resistance is going to be one of the next big areas of focus for public health, but I thought that it was going to happen the moment Apple finally figured out blood glucose measurement through the skin. I did <i>not</i> see a pandemic being part of it.
Insulin Resistance is the start of (all?) metabolic disease. So easy to resolve using fasting, intermittent fasting, keto, carnivore etc diets.<p>Unfortuneately it slowly builds up over decades and only once disease has progressed do Drs move on to treat the resultant disease (and mainly with cholesterol lowering drugs).<p>Instead of measuring fasting glucose levels (which indicate diabetes), insulin levels should be measured as they are the leading indicator.
Given that insulin resistance is strongly correlated with obesity [1], I'm surprised that wasn't a factor they controlled for, especially since the respiratory difficulties associated with obesity seem to be a significant risk factor for death with Covid19 cases.<p>1. <a href="https://obesitymedicine.org/obesity-and-insulin-resistance/" rel="nofollow">https://obesitymedicine.org/obesity-and-insulin-resistance/</a>
Lets not confuse correlation with causation. All this study shows is people with insulin resistance are at significant risk of dying from Covid, it doesn't identify what actually kills them.
However, if you look at the role Vitamin D plays [1] in suppressing cytokine storms, which is what actually pushes over an organism to the point beyond recovery from Covid, and then understand that Vitamin D deficiency is common [2] in Type 2 diabetes, you can begin to understand the fuller picture.<p>1. <a href="https://www.medrxiv.org/content/10.1101/2020.04.08.20058578v4" rel="nofollow">https://www.medrxiv.org/content/10.1101/2020.04.08.20058578v...</a>
2. <a href="https://pubmed.ncbi.nlm.nih.gov/26375925/" rel="nofollow">https://pubmed.ncbi.nlm.nih.gov/26375925/</a>
"[triglyceride and glucose] index was closely associated with the severity and morbidity in COVID-19"<p>So perhaps part of the reason why COVID-19 morbidity is lower in Japan/Korea/Taiwan compared to the U.S. is due to lower prevalence of metabolic syndrome. I wonder if that's also true for Europe.