Heart failure is associated with traditional risk factors like hypertension, diabetes, and coronary artery disease. However, recent research has shown that obesity plays a complex role in heart failure, giving rise to two distinct phenotypes: "fat heart failure" (obese heart failure) and "lean heart failure" (non-obese heart failure).

Fat Heart Failure (Obese Heart Failure)

Obesity is a well-known risk factor for various cardiovascular diseases, including heart failure. "Fat heart failure" typically refers to heart failure in individuals with obesity, and it is more commonly associated with HFpEF (heart failure with preserved ejection fraction). In obese individuals, excess fat, particularly visceral fat, contributes to inflammation, insulin resistance, and metabolic disturbances. These factors can lead to increased cardiac workload and left ventricular hypertrophy, which can progress to HFpEF. Patients with fat heart failure often present with comorbid conditions such as hypertension, type 2 diabetes, and sleep apnea. These conditions can complicate management and worsen outcomes of heart failure.

Interestingly, some studies suggest that obese patients with heart failure may have a better prognosis, a phenomenon known as the "obesity paradox." This paradox suggests that while obesity increases the risk of developing heart failure, once heart failure is established, obese patients may survive longer than their lean counterparts. However, this is still a topic of debate.

Lean Heart Failure (Non-Obese Heart Failure)

Lean heart failure, on the other hand, refers to heart failure in individuals who are not obese. This phenotype is often associated with HFrEF (heart failure with reduced ejection fraction), and frequently linked to ischemic heart disease. It can also be related to other conditions such as valvular heart disease, or cardiomyopathy (genetic, dilated, or inflammatory). Patients with lean heart failure may present with fewer comorbid conditions but often have more severe cardiac dysfunction. So, lean heart failure is generally associated with a worse prognosis compared to fat heart failure.

Which is Worse?

Determining which type of heart failure is worse is complex and depends on various factors, including the patient's overall health condition, the severity of heart failure, and the presence of comorbidity. While lean heart failure is often associated with a worse prognosis due to more severe cardiac dysfunction, fat heart failure presents its challenges, particularly with the management of comorbid conditions like diabetes and hypertension. Moreover, the obesity paradox complicates the direct comparison. Although obese patients may have better short-term survival rates, the long-term complications of obesity, such as atherosclerotic cardiovascular disease or metabolic syndrome, cannot be ignored.