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Weight fluctuation increases risk for death, CV events in patients with CAD
Participants with CAD whose weight has often fluctuated experienced an elevated rate of mortality and CV events, according to findings in The New England Journal of Medicine.
“This study is novel, and we showed that patients who had weight fluctuation itself are associated with significant increases in [CV] events, including the fact that the greater the weight fluctuation, the worse was your outcome,” Sripal Bangalore, MD, MHA, interventional cardiologist and associate professor of medicine at NYU Langone Medical Center, told Cardiology Today.
Researchers analyzed data from 9,509 patients with CAD and LDL levels < 130 mg/dL. Follow-up (median, 4.9 years) was performed every 3 months for the first year, then every 6 months afterward. Participants’ mean baseline weight was 85 ± 15 kg, and median body-weight variability was 1.76 kg.
Body-weight variation
Weight fluctuation was defined as evidence of a participant’s weight variability between follow-up visits. The average variability among consecutive follow-up visits determined the primary variability measure. Participants were split up into four different quintiles depending on their body-weight variability. They were also categorized by their BMI: normal weight (< 25 kg/m2), overweight (25 kg/m2 to < 30 kg/m2) or obese ( 30 kg/m2).
Participants were also grouped by the degree of body-weight variability. High variability (n = 4,755; median age, 60 years; 83% men) was greater than or equal to the median weight, and low variability (n = 4,754; median age, 63 years; 79% men) was below the median.
The primary outcome was any coronary event, defined as CHD death, nonfatal MI, resuscitated cardiac arrest, revascularization or angina. Secondary outcomes included any CV event, MI, stroke, death and new-onset diabetes.
Bangalore, a member of the Cardiology Today Editorial Board, and colleagues reviewed body-weight variability as a time-dependent covariate, and found increases in variability contributed to increases in the following: any coronary event (2,091 events; HR = 1.04, 95% CI, 1.01-1.07), any CV event (2,727 events; HR = 1.04; 95% CI, 1.02-1.07) and death (487 events; HR = 1.09; 95% CI, 1.07-1.12). There was a numerical increase in stroke (HR = 1.05; 95% CI, 0.97-1.13) and MI (HR = 1.04; 95% CI, 0.98-1.09). Similar increases were also observed in the non-time-dependent covariate model, independent of traditional risk factors.
Higher body-weight variability was linked to new-onset diabetes (HR = 1.08; 95% CI, 1.02-1.14). “What we also found interesting was if the patient does not have diabetes at baseline, and they did a lot of weight fluctuations, they tended to develop diabetes,” Bangalore told Cardiology Today. “This was independent of their body weight. We usually associate obesity with developing diabetes, but here, we are showing that it’s not just your body weight, but your weight fluctuation is also an independent predictor of diabetes.”
Risks with weight fluctuation
The higher a participant was in the quintiles of body-weight variability, the higher their rate of any CV event, coronary event, stroke, MI and new-onset diabetes. Compared with those in the lowest quintile, those in the highest quintile experienced increases in the following risks, independent of traditional risk factors: stroke (136%), death (124%), MI (117%), any CV event (85%), new-onset diabetes (78%) and any coronary event (64%).
According to the researchers, participants who had normal weight at baseline and high body-weight variability did not see a significant difference in risk for coronary events compared with those with low body-weight variability, but those who were obese or overweight at baseline with a high variability had a “significantly higher risk” for any CV or coronary event.
“We know from prior studies that in patients that gain a lot of weight over a short period of time or lose a massive amount of weight over a short period of time, that’s stress on the body itself,” Bangalore told Cardiology Today. “There are neurohormonal imbalances and a host of different things that causes the stress on the body. It is possible that smaller changes in weight also have similar effects maybe on a smaller scale, but this combined with the fact that you’re dealing with a high-risk patient, those who already have heart disease, may actually be the cause for worse outcomes.
“Most of the patients have problems keeping the pounds off,” Bangalore told Cardiology Today. “Given this data, we can emphasize that it’s all the more important not just to lose weight, but to keep those extra pounds off and maintain a consistent weight after.” – by Darlene Dobkowski
Disclosure: This study was funded by Pfizer. Bangalore reports receiving personal fees from Abbott Vascular, Boehringer Ingelheim, Daiichi Sankyo, Gilead Sciences, Menarini, Merck and Pfizer. Please see the full study for the other researchers’ relevant financial disclosures.
Perspective
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We’ve known for a number of years that weight cycling may have potentially negative effects on health. There was a study even before that, that showed some potential effects on lipids. This study, although probably not generalizable to the public shows that people who yo-yo in their dieting may be at higher risk for CV events, so it adds to the knowledge base.
There are a number of confounders. First, there are only a certain number of data points of weight, so you don’t always know how much they’re actually fluctuating. On top of that, some people do pretty drastic things to lose weight that may cause weight cycling. One example is, a lot of patients that I take care of will go on ultra-low carb or an Atkins-style diet, which we know can often result in relatively rapid weight loss, but often it’s not sustainable long-term because people don’t feel wonderful on it. Also, many times, it can markedly increase vascular inflammation, especially if high levels of red meat are consumed.
It’s very hard to know all the various potential nutritional effects in what people are doing to lose and regain weight, but we need to have a way to sustainably modify patient behavior to result in long-term, stable weight loss.
The findings also underscore that the vast majority of physicians in this country have very little nutrition training. We are constantly counseling our patients to lose weight, but that by itself is not very effective. It has to be backed up by suggestions of books and other materials to read, courses to take, cooking classes to attend, whatever it might be to support the patient through the process.
A sustained behavioral change requires ongoing maintenance, and a lot of physicians haven’t trained very much in terms of behavioral change or motivational interviewing. We need to come up with ways for patients to sustainably change behavior in a safer way. When you see somebody who’s yo-yoing, this may indicate they’re at higher risk, and that’s an important trigger for us to figure out why they’re having these problems and what we can do to solve them. Figuring out how to lose weight in a safe and sustainable way is the answer.
I always tell my patients that if they were to switch to a more low-fat, plant-based, unprocessed type of diet, that may be where they see the greatest success. A lot of people have posited that on the ultra-low-carb diets, one of the reasons why people are losing weight so rapidly is they’ve stopped eating a lot of the processed foods.
This is just an initial entry into what weight cycling or yo-yo dieting might actually mean. It would be nice to see additional studies in this realm with longer term follow-up. It would be useful to figure out what the patients are doing to lose the weight, and what happens once the weight is lost. It may be interesting to see if people who do things the right way and have a catastrophe in the middle might be better off than the people who are doing the fad diet over and over again.
The increased CV risk in patients who weight cycle may have to do with how they’re losing the weight. It may be that they’re on an ultra-low-carb or a ketogenic diet which may potentially increase their weight. Maybe people are following fad diets or perhaps even taking things like weight-loss supplements, which tend to be stimulants that may have some negative CV effects. There’s a lot here that we don’t know the exact pieces to.
The latest U.S. dietary guidelines for Americans came out, and they only endorsed three diets. One is the Mediterranean diet, one is the vegetable or plant-based diet and the last one is the so-called healthy American diet, which I’m not sure anyone has fully figured out yet. If we can push our patients to a more plant-based or plant-predominant diet, that’s the key to long-term weight loss and CV risk reduction. That’s the real answer. It’s a much harder thing to do in this country because nobody wants to give up their meat and cheese every day.