Obesity Paradox among Heart Failure with Reduced Ejection Fraction Patients: A Retrospective Cohort Study

Background and Objectives: There is consensus on the negative effects of obesity on the development of heart failure. However, several studies have suggested that obesity may have paradoxical survival benefits in heart failure patients. Therefore, the aim of this study is to investigate whether the obesity paradox exists in heart failure with reduced ejection fraction (HFrEF) patients in Jordan. Materials and Methods: In this retrospective cohort study, data were retrieved from electronic hospital records of heart failure patients admitted to King Abdullah University Hospital between January 2010 and January 2020. Patients were divided into five BMI (kg/m(2)) subgroups: (1) Less than 25.0, (2) Overweight 25.0-29.9, (3) Obese Class I 30.0-34.9, (4) Obese Class II 35.0-39.9, and (5) Obese Class III >= 40.0. Changes in patients' clinical and echocardiographic parameters over one year were analyzed. Results: Data of a total of 297 patients were analyzed to determine the effect of obesity on heart failure. The mean age was 64.6 +/- 12.4 years, and most patients (65.7%) were male. Among several co-morbidities, diabetes mellitus and hypertension were the most common and were present in 81.8% and 81.1% of patients, respectively. Over all patients, there was no significant change in EF after 1 year compared to baseline. However, only patients in the Obese Class I group had a statistically significant improvement in EF of 38.0 +/- 9.81% vs. 34.8 +/- 6.35% (p = 0.004) after 1 year. Importantly, among non-diabetic individuals, only Obese Class I patients had a significant (p < 0.001) increase in EF after 1 year compared to other BMI subgroups, a feature that was not observed among patients with diabetes. On the other hand, only Obese Class I patients with hypertension had a significant improvement (p < 0.05) in EF after 1 year compared to other BMI subgroups, a feature that was not observed among patients without hypertension. Conclusions: Our study demonstrates an inverted U-shaped relationship between BMI and EF such that patients with mild obesity (i.e., Obese Class I) had significant improvement in EF compared to those having a lower and higher BMI. We, therefore, suggest the existence of the obesity paradox among HFrEF patients in Jordan.