Factors associated with different patterns of weight change after bariatric surgery: A longitudinal study.

Abstract

The mean weight loss (WL) after successful bariatric surgery is approximately one third of the initial body weight, which is mainly achieved between the first 2years of follow-up. However, 15%-35% of patients do not achieve a significant percentage of total WL (%TWL). Information on factors associated with a higher or lower WL after bariatric surgery is limited. This study aimed to assess the change in %TWL and describe the factors associated with greater or lesser WL over time. This prospective longitudinal study included patients treated with laparoscopic Roux-en-Y gastric bypass or sleeve gastrectomy. Baseline data were recorded before surgery. Follow-up was performed at 3 (n=141), 6 (n=208), 9 (n=115), 12 (n=216), 24 (n=166), and 36months (n=99). Generalized estimating equation analysis was performed to assess the changes in %TWL over time and factors associated with different patterns of WL. In total, 231 patients were included (women, 82.2%; basal body mass index (BMI) 41.4±5.1kg/m2). The tendencies to increase %TWL (32±6.5) were evident in the first year and stabilized thereafter. Sustained nutritionist follow-up (2.3%, p=0.004), baseline BMI >40kg/m2 (0.4%, p<0.001), and WL≥10kg before surgery (0.3%, p=0.001) were associated with a higher %TWL. Patients who performed physical activity >30min/day after surgery reduced their %TWL by 0.6% (p=0.002). Modifiable factors such as nutritional monitoring and WL before surgery are associated with a significant increase in %TWL over time. Basal BMI was associated with a significant decrease in %TWL.