Body Fluid Distribution in the Dynamics of Phase Angle During Different Stages of Weight Loss Induced by Gastric Bypass
Name: BEATRIZ BOBBIO DE BRITO
Publication date: 03/07/2025
Examining board:
Name |
Role |
|---|---|
| ANDRESSA BOLSONI LOPES | Coorientador |
| FABIANO KENJI HARAGUCHI | Presidente |
| JOANA FERREIRA DO AMARAL | Examinador Externo |
| LUIS CARLOS LOPES JUNIOR | Examinador Interno |
Summary: Introduction: The phase angle (PhA) is underexplored in severe obesity and
after bariatric surgery, despite being a relevant indicator that reflects
bodily and cellular changes during weight loss. Objective: This study aimed
to evaluate the dynamics of the phase angle (PhA) and identify the factors
associated with body composition over a 12-month period following Roux-en-Y
gastric bypass (RYGB) surgery. Material and Methods: Analytical observational
retrospective cohort study with male and female patients who underwent RYGB,
with body composition assessed at four time points: before surgery and at 2, 6, and 12
months postoperatively. Data were analyzed using the Friedman test with a
significance level of 5%. Spearman correlation and multiple linear regression
were also performed. Results: From a large screened cohort, 60 patients
completed the full longitudinal analysis. PhA values decreased after RYGB and
stabilized over time. Weight, BMI, waist circumference, fat mass, fat-free
mass, and total body water significantly decreased at each assessment point
(p<0.05). PhA values were associated with the extracellular-to-intracellular
water ratio (ECW:ICW ratio) at the postoperative time points (p<0.05).
Conclusion: PhA values tend to decrease initially after RYGB, followed by
later stabilization, with the ECW:ICW ratio being the main determinant in the
postoperative period. However, given the complexity of severe obesity, other
factors may also influence PhA in the preoperative period, highlighting the
need for a multifactorial interpretation and future analytical studies.
