Cardiopulmonary exercise test and bioimpedance as prediction tools to predict the outcomes of obesity treatment

INTRODUCTION Obesity impacts the global population. Bioelectrical impedance analysis (BIA) and cardiopulmonary exercise test [CPET]) may help modify the treatment. OBJECTIVES We aimed to compare BIA and CPET results in obese and lean indivisuals, assess changes in BIA and CPET during obesity treatment, and indentify parameters predicting treatment outcome. PATIENTS AND METHODS We enrolled 200 obese patients, of whom 45 underwent a lifestyle modification treatment, and 32 lean individuals (controls). Lifestyle modifications included diet, rehabilitation, education, and behavioral therapy. The diet was based on body composition assessed by BIA and fat metabolism assessed by CPET. The intensity of exercise in the rehabilitation program was based on CPET, mainly peak oxygen uptake (VO2peak), fat metabolism (FAT), and fat heart rate (FAT HR). The protocol duration was 12 weeks. RESULTS Obese patients differed from lean controls with regard to VO2peak (P < 0.0001), oxygen uptake at anaerobic threshold (P < 0.0002), respiratory exchange ratio (P < 0.014), oxygen uptake to work rate slope (P < 0.0004), FAT (P < 0.001), FAT HR (P < 0.0008), anaerobic threshold heart rate (P < 0.0003), as well as fat mass (P = 0.01), fat-free mass (P = 0.007), resting metabolic rate (RMR) (P = 0.007), total body water (P = 0.01), and extracellular water (P = 0.004). The treatment resulted in increased RMR (P < 0.02) and VO2peak (P < 0.002), as well as reduced fat tissue (P < 0.006) and resting heart rate (P < 0.017). The prediction model based on FAT HR, resting heart rate, and FAT enabled the prediction of treatment outcomes in 92% of patients. CONCLUSIONS Obese patients had pathological FAT and impaired exercise tolerance. Changes in BIA and CPET prove the metabolic impact of lifestyle modification treatment.