Variables psicológicas y su relación con la evolución del índice de masa corporal en personas sometidas a cirugía bariátrica

Background: Bariatric surgery is one of the effective options for the reduction of body weight, however, there is no clarity regarding the postoperative weight loss curve, moreover, there are findings that suggest wide individual variability and the factors associated with this phenomenon are not clear yet. Aim: This study sought to identify the influence of psychological factors such as eating self-efficacy, eating patterns and social support on the variation of BMI in patients who have undergone bariatric surgery through the surgical technique of vertical sleeve gastrectomy. Materials and Method: A total of 31 operated patients in a public hospital in southern Chile participated in the study. The Gompertz growth curve was used to model BMI variation curves and nonlinear regression to ascertain the influence of the study variables. Results: The maximum weight loss occurs around the ninth month after surgery. The initial BMI shows a significant difference in the reduction of BMI (p = 0.04) as well as the social support perceived and the sub-factor friends (p = 0.03). The psychological variables, treated individually, had no effect on the weight variation curve; however, when treated as a group, they were able to predict the maximum of weight loss and its speed, even controlling for the initial BMI. Discussion: According to previous studies, these findings confirm that the individual variability in the evolution of BMI after surgery is affected by psychosocial factors. Conclusion: Pre-surgical assessment and post-surgery follow-up are recommended, taking into account not only biomedical variables but also psychological factors.