Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A Way to Reverse Coronary Artery Disease? [pdf]

jfponline.com

Post reply on HN
Print view View original

51–60 of 65 posts

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#51

Post by collyw »

ghkbrew wrote: post #23
analog31 wrote: post #12

Earlier quoted context omitted.

I'm not trying to quibble, but am genuinely curious: What would a control group consist of? There were plenty of patients who didn't receive the trial program, at large in the general population. And it couldn't have been a blind study, because the patients knew what they were eating.

> What would a control group consist of? It would be an equivalent population who weren't asked to change their diets. There are multiple reasons the patients in this study might not be comparable to participants in other studies or to the general population. Age, gender, average disease severity all need to be controlled for. And if nothing else the simple fact the patient knows they're being monitored could have an…

Is that not standard advice when you have a heart attack. Give up smoking, eat healthier, do a bit of exercise. It's going to be difficult to find a willing and valid control group under the circumstances.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#52

Post by justin66 »

melling wrote: post #43

Didn't Bill Clinton switch to a vegan diet to "manage" his heart disease? Think I saw it discussed on CNN. Here's a NYT article that I found on it: http://well.blogs.nytimes.com/2011/08/18/bill-clintons-vegan...

One of the authors of the paper - Essylstyn - is someone he works with on his heart disease.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#53

Post by robbiep »

Allow me to don my doctor hat and provide some comment here. I'll leave the statistical analysis to the mathematicians below.

1. The study was self-selected - we don't know to what degree. Did they place flyers in vegetarian recruiting grounds?

2. They explicitly state that they are not including 8 patients that experienced thrombotic or embolic events or had progression, blaming them on other factors. That may be the case, but it is not ok to exclude patients on that basis and report your adverse event as 1% due to that.

3. There is no marker of cardiac function provided in the study / we have no idea if the groups had similar baseline function.

This is a critical point because amongst the 'non-adherent' group there is one patient who underwent a heart transplant. A heart transplant is a very rare procedure and is only reserved for extremely severe heart failure. If a patient in a study eventually underwent a heart transplant, that patient very likely had horrific cardiac function at the beginning of the trial.

What is more telling is that such information could have been statistically provided very easily: They could have chosen to provide a summary of number of patients who had experienced infarcts; number of patients with aberrant ECG rhythms; number of patients on spironolactone (a medication reserved for use for late in heart failure); Left ventricular ejection fraction estimated from TTE; The list goes on.

Instead they provide only the sexes, 'symptom reduction', and adverse events.

In my opinion this study provides little more than anecdote that patients should switch entirely to a plant based diet, and at this point I would certainly not recommend a patient of mine to switch. However it should be studied in greater detail and it would be interesting if stronger evidence emerged.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#54

Post by justin66 »

ghkbrew wrote: post #23
analog31 wrote: post #12

Earlier quoted context omitted.

I'm not trying to quibble, but am genuinely curious: What would a control group consist of? There were plenty of patients who didn't receive the trial program, at large in the general population. And it couldn't have been a blind study, because the patients knew what they were eating.

> What would a control group consist of? It would be an equivalent population who weren't asked to change their diets. There are multiple reasons the patients in this study might not be comparable to participants in other studies or to the general population. Age, gender, average disease severity all need to be controlled for. And if nothing else the simple fact the patient knows they're being monitored could have an…

> It would be an equivalent population who weren't asked to change their diets.

Which is actually an ethical quandary when you think about it. A doctor's ethics are really tested when he has to say to some patients "sure, I think you should change your diet and you'll probably die if you don't, but you're part of the control group!"

One more ethical (and still statistically somewhat interesting) way of administering such a study would be to bring in doctors advocating different sorts of diets. The Cleveland Clinic hasn't done such a thing but they probably could: they've got a group that advocates the rigid vegan diet and another that advocates the Mediterranean diet. Not as good as having a control group that continues to subsist on cheeseburgers and coke but it actually can test a few specific ideas, like the vegan claim.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#55

Post by acconrad »

robbiep wrote: post #53

Allow me to don my doctor hat and provide some comment here. I'll leave the statistical analysis to the mathematicians below. 1. The study was self-selected - we don't know to what degree. Did they place flyers in vegetarian recruiting grounds? 2. They explicitly state that they are not including 8 patients that experienced thrombotic or embolic events or had progression, blaming them on other factors. That may be th…

I'm surprised you didn't point out that the diet itself was flawed. The basis of the plant-based diet was vegetables and fruits, and yet they explicitly excluded fructose. You can't have any fruits then! Nearly every fruit contains fructose in some appreciable amount, among the lowest in concentrations are raspberries and strawberries. Even vegetables have significant amounts of fructose, such as asparagus and tomatoes (though technically a fruit as well). I feel like with a study that self reports from it's patients, especially of this size, a diet this restrictive is nearly impossible to keep 24/7.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#56

Post by Thriptic »

This is a pretty poorly conducted study. First off, they make a causal claim that nutritional intervention induced reversal of CAD progression. This is an observational study so such a claim is inappropriate. This is also a very bold claim and yet this paper is published in a shit journal with an impact factor of Indeed, there are huge limitations in this study:

1. No control group

2. Self reported dietary adherence

3. Obvious possibility of the healthy adherer effect (people who voluntarily present for interventions and are adherent to dietary changes will probably also exhibit other healthy behaviors like exercise, mood control, better sleep etc which introduces confounders.

4. No monitoring of medication adherence. Perhaps these people simply started taking their medications more regularly while in this program. Medication adherence among patients with CAD is notoriously terrible.

5. Possibility of sick stopper effect in their non-adherers (sickest people also most likely not to take their meds, precipitating worse outcomes).

6. They note that on average their patients lost 18 lbs; perhaps weight loss alone was responsible for their improvements

7. They exclude some of their sickest patients

8. They report symptom relief in adherent patients but don't mention what that means. Do they report less angina? Did they see plaque size reduction? If the former, you have introduced potential for placebo effect.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#57

Post by The_Pherocity »

pessimizer wrote: post #49
The_Pherocity wrote: post #10

Earlier quoted context omitted.

Considering it states exactly that in the article in two places, I's say it's a safe assumption.

That quote is from the article, yes. But they repeatedly summarize the diet as "plant-based", rather than sugar-free and plant-based. What if the fact that they cut meat had absolutely no effect or even a negative one ? Would we be able to tell from this?

That's a fantastic question, and one that I really like to know the answer to, but not the question I replied to. It is indeed what they removed, which caused the problem. And the diet they ate was also "plant based". Now we just need more studies to nail down which of that large list is actually the culprit. Like yourself, I highly doubt that it's all of them.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#59

Post by JDDunn9 »

collyw wrote: post #47
JDDunn9 wrote: post #34

Earlier quoted context omitted.

Control and double blind studies are more important when the placebo effect and subjective outcomes are at play. Not necessary here. Everyone that follows a different diet would like to complain about that. You should have compared it to the paleo diet, or low-carb diet, or whatever. Show studies that those diets have similar effects and then they merit comparison. Self reporting is an issue, but this is not the only…

My friend, (a scientist) wants to develop a pill that "triggers" the placebo effect (lets face it, its as effective as many drugs). Could you test that?

Sure, but you would just be testing it against other placebos. There has been work in this area. For instance getting a pill from a doctor is stronger than getting the same pill from a stranger. The look/cost of the pill affects it's strength, etc.

Re: A Way to Reverse Coronary Artery Disease? [pdf]

#60

Post by rjurney »

I emailed asking for the slides. I got this reply:

My husband’s book, Prevent and Reverse Heart Disease is widely available. ‘ On his web site, dresselstyn.com you will find his counseling DVD for purchase

Or you may come to the Cleveland Clinic Wellness Institute for his monthly counseling seminar. Details available through his secretary Jackie at 216-448-8556.

Post reply on HN