The Impact of Body-Mass Index on Cardiopulmonary Fitness in Chinese Heart Failure Patients

Abstract

Introduction Body-mass index (BMI) and cardiopulmonary fitness measured by peak oxygen consumption (VO2peak) are inversely related among healthy Caucasians. However, knowledge of Chinese heart failure patients remains scant because they experience significant impaired cardiopulmonary fitness, and Asians have lower BMI cut-offs than whites. Hypothesis Evaluate whether Asian-specific BMI cut-offs for overweight (23 kg/m2) and obese (27.5 kg/m2) reflect significant VO2peak changes, and BMI's impact on VO2peak in Chinese heart failure patients. Methods In this cross-sessional study, data was collected from 70 heart failure patients with NYHA class I∼IV (83% II) and mean ejection fraction of 46.3% in Guangdong Provincial Hospital of Chinese Medicine. Height and weight were measured to calculate BMI; and VO2peak was measured via symptom-limited bicycle exercise test. Participants were categorized as healthy (BMI 18.5-22.9 kg/m2), overweight (BMI 23-27.4 kg/m2), or obese (BMI ≥27.5 kg/m2). Those with BMI below 18.5 kg/m2 were excluded. Between-group differences were identified by one-way ANOVA and post-hoc analysi. Spearman's correlation coefficients and binary linear regression evaluated the relationship between BMI and VO2peak. p Results Among 70 patients, 24 (34%) were classified healthy (BMI >18 kg/m2), 34 (49%) overweight (BMI 23-27.4 kg/m2), and 12 (17%) obese (BMI ≥27.5 kg/m2). VO2peak differed between the three BMI groups (p=0.017); and the obese group had significantly lower VO2peak than the heathy group (-3.9 mL/kg/min, 95%CI: -6.6, -1.2). When patients were sex-age stratified (young: Conclusion Asian-specific BMI cut-offs are useful clinical instruments for detecting statistically relevant decreases in VO2peak among heart failure patients. A negative association exists between BMI and VO2peak, especially in those under 60. For each 1.5 unit increase in BMI, reducing VO2peak showed a clinically significant 1 mL/kg/min decrease among heart failure patients. Larger sample-size research could reveal robust quantitative relationships between BMI and cardiopulmonary fitness.