Are these CAD study findings too good to be true?

I read with interest “A way to reverse CAD?” by Esselstyn et al (J Fam Pract. 2014;63:356-364,364a,364b) on the effects of a plant-based nutrition program on the incidence of cardiac events in patients with cardiovascular disease (CVD). If found to be effective in subsequent studies, this intervention could have tremendous clinical implications for patients. However, the article left me with many questions and concerns.

One of my concerns is that the article was written in a promotional, not scientific, tone. Although no potential conflicts of interest were reported, the lead author has published books on the topic from which he could profit. Even if one were to disregard these concerns, several methodological issues remain.

Specifically, Esselstyn et al report that over a mean 3.7 years of follow-up, 89% of patients were compliant to the program, defined as avoidance of all meat, fish, dairy, and added oils. Frankly, this statistic isn’t believable because the “compliant” patients undoubtedly consumed these products on occasion during this period. More likely, compliance was assessed by a simple Yes or No response over the phone; expectation bias would strongly influence patient reporting in this situation.

In addition, there’s no comparison of disease severity, prior interventions, weight loss, assessment of optimized medical management, or follow-up duration between the 2 groups. The differences in events reported in this study may be explained by unreported confounders.

The authors should be congratulated for presenting this work, but overall, the reporting is inadequate to form any scientific conclusions. The data lead to more questions than answers.

Larry E. Miller, PhD
Asheville, NC

Esselstyn et al report an extraordinary recurrent event rate of 0.6% among 177 patients with established cardiovascular disease who adhered to a plant-based diet for approximately 44 months. These results are so remarkable that several questions come to mind. Why didn’t the editors of The Journal of Family Practice offer any commentary on a revolutionary intervention that appears to cure cardiovascular disease? Why aren’t these results being reported and commented upon in the lay media? Why didn’t the journal note Dr. Esselstyn’s potential conflict of interest as an author who profits from the sale of books that advocate a plant-based diet?

I am glad to see studies that look at nutritional interventions getting equal billing with those funded by pharmaceutical companies, but publishing this report without comment certainly leads a reader to believe that the editors and peer reviewers accept this study at face value, and that physicians might practice accordingly.

David A. Silverstein, MD
Buffalo, NY

Authors' response:
We agree with the major point of Dr. Miller’s comments—this safe, inexpensive, and effective diet works so well at reducing coronary and other vascular disease that it raises more questions than answers, and deserves study by other groups. There was no intent to obscure the senior author’s 2007 book, Prevent and Reverse Heart Disease¹; as it is mentioned in the article, a copy of the book was provided to each study participant, and it was listed among the references.

We agree that using standardized, validated instruments to evaluate dietary intake, such as food frequency questionnaires or 3- to 7-day food records, would provide more scientifically sound methodology, but we were able to assess several key features of the diet, including the 2 key ones, abstinence from animal food intake and avoidance of all oils, without such tools. Most patients transitioned to the whole foods plant-based diet from the meat and processed foods dietary pattern, with only a few eating ovo-lacto or lacto-vegetarian diets before participating in the study.

Regarding disease severity, 44 participants had a prior myocardial infarction and 119 had a prior percutaneous coronary intervention or coronary artery bypass graft surgery. Twenty-seven were scheduled for intervention that was unnecessary after they adopted the program. The frustration of current cardiovascular therapy and the potential of plant-based nutrition are succinctly expressed in our recent series of case reports.²

Caldwell B. Esselstyn Jr, MD
Mladen Golubic, MD, PhD
Michael F. Roizen, MD
Lyndhurst, Ohio

I read with interest “A way to reverse CAD?” by Esselstyn et al (J Fam Pract. 2014;63:356-364,364a,364b) on the effects of a plant-based nutrition program on the incidence of cardiac events in patients with cardiovascular disease (CVD). If found to be effective in subsequent studies, this intervention could have tremendous clinical implications for patients. However, the article left me with many questions and concerns.

One of my concerns is that the article was written in a promotional, not scientific, tone. Although no potential conflicts of interest were reported, the lead author has published books on the topic from which he could profit. Even if one were to disregard these concerns, several methodological issues remain.

Specifically, Esselstyn et al report that over a mean 3.7 years of follow-up, 89% of patients were compliant to the program, defined as avoidance of all meat, fish, dairy, and added oils. Frankly, this statistic isn’t believable because the “compliant” patients undoubtedly consumed these products on occasion during this period. More likely, compliance was assessed by a simple Yes or No response over the phone; expectation bias would strongly influence patient reporting in this situation.

In addition, there’s no comparison of disease severity, prior interventions, weight loss, assessment of optimized medical management, or follow-up duration between the 2 groups. The differences in events reported in this study may be explained by unreported confounders.

The authors should be congratulated for presenting this work, but overall, the reporting is inadequate to form any scientific conclusions. The data lead to more questions than answers.

Larry E. Miller, PhD
Asheville, NC

Esselstyn et al report an extraordinary recurrent event rate of 0.6% among 177 patients with established cardiovascular disease who adhered to a plant-based diet for approximately 44 months. These results are so remarkable that several questions come to mind. Why didn’t the editors of The Journal of Family Practice offer any commentary on a revolutionary intervention that appears to cure cardiovascular disease? Why aren’t these results being reported and commented upon in the lay media? Why didn’t the journal note Dr. Esselstyn’s potential conflict of interest as an author who profits from the sale of books that advocate a plant-based diet?

I am glad to see studies that look at nutritional interventions getting equal billing with those funded by pharmaceutical companies, but publishing this report without comment certainly leads a reader to believe that the editors and peer reviewers accept this study at face value, and that physicians might practice accordingly.

David A. Silverstein, MD
Buffalo, NY

Authors' response:
We agree with the major point of Dr. Miller’s comments—this safe, inexpensive, and effective diet works so well at reducing coronary and other vascular disease that it raises more questions than answers, and deserves study by other groups. There was no intent to obscure the senior author’s 2007 book, Prevent and Reverse Heart Disease¹; as it is mentioned in the article, a copy of the book was provided to each study participant, and it was listed among the references.

We agree that using standardized, validated instruments to evaluate dietary intake, such as food frequency questionnaires or 3- to 7-day food records, would provide more scientifically sound methodology, but we were able to assess several key features of the diet, including the 2 key ones, abstinence from animal food intake and avoidance of all oils, without such tools. Most patients transitioned to the whole foods plant-based diet from the meat and processed foods dietary pattern, with only a few eating ovo-lacto or lacto-vegetarian diets before participating in the study.

Regarding disease severity, 44 participants had a prior myocardial infarction and 119 had a prior percutaneous coronary intervention or coronary artery bypass graft surgery. Twenty-seven were scheduled for intervention that was unnecessary after they adopted the program. The frustration of current cardiovascular therapy and the potential of plant-based nutrition are succinctly expressed in our recent series of case reports.²

Caldwell B. Esselstyn Jr, MD
Mladen Golubic, MD, PhD
Michael F. Roizen, MD
Lyndhurst, Ohio

I read with interest “A way to reverse CAD?” by Esselstyn et al (J Fam Pract. 2014;63:356-364,364a,364b) on the effects of a plant-based nutrition program on the incidence of cardiac events in patients with cardiovascular disease (CVD). If found to be effective in subsequent studies, this intervention could have tremendous clinical implications for patients. However, the article left me with many questions and concerns.

One of my concerns is that the article was written in a promotional, not scientific, tone. Although no potential conflicts of interest were reported, the lead author has published books on the topic from which he could profit. Even if one were to disregard these concerns, several methodological issues remain.

Specifically, Esselstyn et al report that over a mean 3.7 years of follow-up, 89% of patients were compliant to the program, defined as avoidance of all meat, fish, dairy, and added oils. Frankly, this statistic isn’t believable because the “compliant” patients undoubtedly consumed these products on occasion during this period. More likely, compliance was assessed by a simple Yes or No response over the phone; expectation bias would strongly influence patient reporting in this situation.

In addition, there’s no comparison of disease severity, prior interventions, weight loss, assessment of optimized medical management, or follow-up duration between the 2 groups. The differences in events reported in this study may be explained by unreported confounders.

The authors should be congratulated for presenting this work, but overall, the reporting is inadequate to form any scientific conclusions. The data lead to more questions than answers.

Larry E. Miller, PhD
Asheville, NC

Esselstyn et al report an extraordinary recurrent event rate of 0.6% among 177 patients with established cardiovascular disease who adhered to a plant-based diet for approximately 44 months. These results are so remarkable that several questions come to mind. Why didn’t the editors of The Journal of Family Practice offer any commentary on a revolutionary intervention that appears to cure cardiovascular disease? Why aren’t these results being reported and commented upon in the lay media? Why didn’t the journal note Dr. Esselstyn’s potential conflict of interest as an author who profits from the sale of books that advocate a plant-based diet?

I am glad to see studies that look at nutritional interventions getting equal billing with those funded by pharmaceutical companies, but publishing this report without comment certainly leads a reader to believe that the editors and peer reviewers accept this study at face value, and that physicians might practice accordingly.

David A. Silverstein, MD
Buffalo, NY

Authors' response:
We agree with the major point of Dr. Miller’s comments—this safe, inexpensive, and effective diet works so well at reducing coronary and other vascular disease that it raises more questions than answers, and deserves study by other groups. There was no intent to obscure the senior author’s 2007 book, Prevent and Reverse Heart Disease¹; as it is mentioned in the article, a copy of the book was provided to each study participant, and it was listed among the references.

We agree that using standardized, validated instruments to evaluate dietary intake, such as food frequency questionnaires or 3- to 7-day food records, would provide more scientifically sound methodology, but we were able to assess several key features of the diet, including the 2 key ones, abstinence from animal food intake and avoidance of all oils, without such tools. Most patients transitioned to the whole foods plant-based diet from the meat and processed foods dietary pattern, with only a few eating ovo-lacto or lacto-vegetarian diets before participating in the study.

Regarding disease severity, 44 participants had a prior myocardial infarction and 119 had a prior percutaneous coronary intervention or coronary artery bypass graft surgery. Twenty-seven were scheduled for intervention that was unnecessary after they adopted the program. The frustration of current cardiovascular therapy and the potential of plant-based nutrition are succinctly expressed in our recent series of case reports.²

Caldwell B. Esselstyn Jr, MD
Mladen Golubic, MD, PhD
Michael F. Roizen, MD
Lyndhurst, Ohio