Usefulness of Baltasar's expected body mass index as an indicator of bariatric weight loss surgery

Introduction: Determining the best indicator to report weight loss takes on special relevance following bariatric surgery. Our objective is to apply a method proposed by Baltasar et al. to express weight loss results following bariatric surgery.

Materials and methods: Anthropometric data were collected from 265 patients who had undergone Sleeve gastrectomy (SG, n = 172) and Roux-en-Y gastric bypass (RYGBP, n = 93) with a 2-year follow-up period. Initial BMI was calculated as well as BMI 2 years after, percentage of excess BMI loss (PEBMIL), expected BMI (EBMI), and corrected PEBMIL.

Results: In SG group, average BMI 2 years after surgery fell within a 95 % CI of expected BMI, with an average BMI of 31.58 ± 4.05 kg/m² in 35-45 BMI group, an average BMI of 33.62 ± 4.96 kg/m² in 45-55 BMI group, and an average BMI of 37.40 ± 5.93 kg/m² in 55-65 BMI group. In RYGBP group, average BMI 2 years after the surgery was below than average expected BMI (28.76 ± 3.20 kg/m² in 35-45 BMI group and 29.71 ± 3.30 kg/m² in 45-55 BMI group). Results are considered excellent for the group with an initial BMI of above 45 kg/m².

Conclusions: EBMI is a good weight loss indicator, mainly when 95 % CI is taken into account. EBMI is consistent with the results obtained 2 years after surgery in our patients who underwent SG and RYGBP. Corrected PEBMIL is a good indicator for expressing the percentage of BMI loss and offers more realistic values than conventional formula with a cut-off point of 25 points.