24 Mar Obesity Paradox: Overweight Heart Failure Patients Have Best Prognosis
MedicalResearch: What is the background for this study?
Authors: Heart failure (HF) is the second most common cause of hospitalization after child delivery in the US. In general, increasing degrees of obesity have been associated with progressively worse outcomes among individuals without known cardiovascular (CV) diseases. Therefore intentional weight loss, via structured dietary and exercise training programs or bariatric surgery, has been suggested to reverse hemodynamic and cardiac structural changes associated with obesity. However, several recent studies have reported lower mortality and morbidity among heart failure patients who were overweight or obese compared with those whose weight was normal or subnormal. This phenomenon has been commonly labeled the “obesity paradox” or “reverse epidemiology.” These findings question the prognostic significance of BMI and the practice of extrapolating findings derived from the general population to HF patients.
Reasons for the association between BMI and all- cause and CV mortality and hospitalizations in HF are not fully understood. Due to contradictory results in various studies and lack of definitive data on prognostic value of BMI and its purposeful alteration in HF, the American College of Cardiology Foundation/American Heart Association do not provide any firm recommendations for purposeful weight loss in heart failure. To further explore the relationship between obesity and outcome in heart failure patients, we systematically examined the association between BMI and all- cause mortality, CV mortality and hospitalizations among patients with chronic heart failure.
MedicalResearch: What are the main findings? What should clinicians and patients take away from your report?
Authors: Our results show that, risk of all-cause and CV mortality and hospitalization was highest among chronic heart failure patients who were underweight as defined by low BMI; the best prognosis was noted in the overweight BMI patients at the end of a mean follow up period of 2.85 years. These findings support the existence of an “obesity (or ‘overweight’) paradox”.
Our results suggest that it is not doomsday for the heart failure patient who is overweight or mildly obese. Previously, if we were sitting with 2 HF patients, one with BMI 22 and the other 32, we would have been more worried about the heavier patient-now our results suggest that we should be more worried about the thinner one, even more so about the HF patient with BMI of 18.
Our results point to a more complex relationship between patient weight and outcome among patients with chronic heart failure. It is premature to derive any concrete recommendations from these results since our results do not assess weight loss or even weight changes over time. It is conceivable that we don’t capture factors that may at least in part explain these results. For example, it is possible that we see worse outcome in low BMI patients because they have the most advanced disease stages or most progressive courses while those with higher BMI are early in the disease process.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Authors: Further prospective studies are needed to investigate and explore
a) the potential underlying mechanisms behind this obesity or “overweight” paradox and
b) potential benefits or risks of change in weight and impact of various nutritional interventions in patients with heart failure in order to develop beneficial therapeutic strategies for the patients at greatest risk.
Sharma A1, Lavie CJ2, Borer JS3, Vallakati A4, Goel S5, Lopez-Jimenez F6, Arbab-Zadeh A7, Mukherjee D8, Lazar JM9. Am J Cardiol. 2015 Feb 18. pii: S0002-9149(15)00720-1. doi: 10.1016/j.amjcard.2015.02.024. [Epub ahead of print]
MedicalResearch.com Interview with: Abhishek Sharma MD (on behalf of all co-authors) (2015). Obesity Paradox: Overweight Heart Failure Patients Have Best Prognosis