Obesity Paradox in Atrial Fibrillation: Implications for Outcomes and Relationship With Oral Anticoagulant Drugs

Marco Proietti; Giuseppe Boriani


Am J Cardiovasc Drugs. 2020;20(2):125-137. 

In This Article

Abstract and Introduction


In the last 40 years, concern about the obesity epidemic has increased. Data from the current literature highlight a strong relationship between obesity and atrial fibrillation (AF), particularly in relation to an increased risk for incident and recurrent AF. A phenomenon called the "obesity paradox" has emerged: the apparently counterintuitive evidence from epidemiological data indicating that overweight and obese patients may have a better prognosis than healthy-weight patients. A differential impact of oral anticoagulants (OACs) in terms of effectiveness and safety in the various body mass index categories has been postulated, particularly in the comparison between non-vitamin-K antagonist oral anticoagulants and vitamin K antagonists. This review aims to summarize the evidence on the impact of obesity in patients with AF, focusing on descriptions of the obesity paradox and its relationships with OAC treatment.


Obesity is well recognized as a major health condition. It currently affects millions of people and is now considered an epidemic. In particular, it has been demonstrated that, in the last 40 years, population body mass index (BMI) has progressively increased, in both adults and children and irrespective of geographic location.[1] Overweight and obesity have been largely recognized as a major risk factor for adverse clinical outcomes, particularly for cardiovascular outcomes.[2,3] This notwithstanding, the complex interplay between overweight/obesity and cardiovascular health is still far from completely understood, particularly regarding their proper assessment and the differential impact of fat distribution patterns.[4]

Obesity is one of the relevant risk factors for the development of atrial fibrillation (AF).[5,6] The relationship between obesity and AF has been established by several studies.[7,8] In particular, in 2008, Wanahita et al.[8] conducted a systematic review and meta-analysis, documenting that obese patients had an increased relative risk of developing AF, with greater risk associated with higher BMI. Since then, further relevant evidence has been accumulated about the strong relationship between obesity and AF.[9]

In recent years, clinical research in the field of obesity studies has revealed the so-called obesity paradox.[10,11] This term relates to the apparently counterintuitive phenomenon wherein obese patients with cardiovascular diseases seem to have a lower risk of short- and long-term adverse events.[10,11] This phenomenon has thus far been described in patients with hypertension, heart failure, coronary artery disease, peripheral artery disease and other cardiovascular and non-cardiovascular conditions.[11] An obesity paradox has also been described for patients with AF.[6]

The aim of this review is to briefly describe the patho-physiological and epidemiological relationship between obesity and AF and to describe the evidence related to the obesity paradox in AF and its relationship with oral anticoagulants (OACs).