New Connections Between AF and Other Risk Factors
Isabelle C. Van Gelder, MD, PhD
Interview | In recent years, there have been important improvements in managing patients with atrial fibrillation (AF). Because of changing lifestyles and an aging population, however, we may not know as much about the incidence and risk factors for AF as we thought. CardioSource WorldNews spoke to Isabelle C. Van Gelder, MD, PhD, about the community-based study from The Netherlands that studied these incidences and their relation to cardiovascular events, heart failure, and mortality.
CSWN: First, give us a sense of why you
did this study. Our understanding on this issue has changed—is that what you were looking for?
Isabelle C. Van Gelder, MD, PhD: Yes, our understanding of AF incidences has changed. What we know now comes especially from American epidemiological studies and the Framingham Heart Study—but these are rather old studies. So we had the opportunity to examine it; this study was started by our nephrology department—with whom we had worked before—and, because they have EKGs, we had the possibility and the opportunity to look at the incidence of AF. More than 8,000 people were included in the trial back in 1997, and we now have a follow-up of almost 10 years with this analysis. We saw the study participants—not patients at that moment—every 3 years at our department and other hospitals nearby. The review was performed only in The Northern Netherlands; those people who live there do not usually move, so we had a very good follow-up.
So we thought we understood the risk factors from the dated data. What are we learning now?
Important risk factors for AF are advanced age, being male, prior myocardial infarction, prior stroke, and hypertension, of course. So that’s already well-known. What we now learn is that obesity is a very important risk factor. Five points in BMI elevation means a 50% increase in the risk of AF. So if you go from 25 to 30 BMI points, then your risk is increased by 45%. We also considered the well-known work from Prashanthan Sanders, MBBS, PhD, who shows that if you reduce weight and you perform a little bit of physical activity then the AF burden reduces.
So, for example, in The Netherlands, we bike. The Netherlands is very small, and I only live 10 km from my hospital, so I have the opportunity to bike. And a lot of people in the Netherlands do bike, but we all know that our lifestyles have changed, and it is very difficult to not become obese. In my outpatient clinic, a lot of people who are sitting in front of me because of AF are obese.
Did you find any other connections that you thought there might be?
Well, actually after multi-variant analysis, B-type natriuretic peptide (BNP) was a predictor. We also have learned more that HF is a preserved ejection fraction (HFpEF). All the data are about HF with a reduced ejection fraction (HFrEF), and even in our population the incidence of reduced ejection fraction was higher than HFpEF. This is because making the diagnosis of HFpEF is very difficult. But everybody knows that the patients with AF who deteriorate once they have an episode of AF are typical HFpEF patients. And that’s also something in the future that we have to learn: the incidence of HFpEF will increase, and the link between AF and HFpEF is important.
And last year we also published another paper; we wrote it with other AF researchers like Robert George Weiss, MD, of Johns Hopkins. We showed that AF almost never comes alone, that lone AF doesn’t exist. So obesity is an important risk factor, but probably working with other things we do not yet know. And genetics also plays a role. So, in the next community-based study on the incidence of AF, we’ll learn even more.
So you found that obesity has become a major risk factor for AF and the incidence of AF doubles the cardiovascular event risk, all-cause mortality risk, and HF risk fivefold. If you can prevent one of them, it can help you prevent other factors, too.
Yes, fivefold, and I think that’s important. When AF occurs, then the risk for stroke, for HF, and for mortality significantly increases.
We can’t prevent it but we can try. Through lifestyle and risk-factor management, we can reduce the AF burden and also reduce the cost for AF.
- Vermond RA, Geelhoed B, Verweij N, et al. J Am Coll Cardiol. 2015;66(9):1000-7.
Keywords: CardioSource WorldNews, Atrial Fibrillation, Cardiovascular Diseases, Heart Failure, Life Style, Residence Characteristics, Risk Factors
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