Laparoscopic sleeve gastrectomy conversion to gastric bypass: conversion rate over time, predictors of conversion, and weight loss outcomes.

Background: Laparoscopic sleeve gastrectomy (LSG) is the most common Bariatric procedure in the United States; however, the frequency of conversion to Roux-en-Y gastric bypass (RYGB) is unknown.

Objectives: The primary aim was to determine the conversion rate over time from LSG to RYGB. The secondary objectives were to evaluate factors associated with conversion and postconversion weight loss outcomes.

Setting: Single Academic Institution, Center of Bariatric Excellence.

Methods: A retrospective analysis of all LSG from 2011 to 2020 was done. Kaplan-Meier analysis was utilized to estimate the conversion rate over time after LSG. Cox regression was utilized to identify predictors of future conversion.

Results: Of 875 LSGs, 46 were converted to RYGB from 2011 to 2020. Median follow-up was 2.6 years, and 7-year follow-up rate was 59.9%. The 1-year conversion rate was 1.4%, increasing to 3.8%, 9.0%, and 12.6% at 3, 5, and 7 years respectively. Female gender (hazard ratio [HR] = 4.2, P = .05) and age <55 (HR = 3.5, P = .04) were associated with greater chance of conversion. Preoperative asthma (HR = 1.7, P = .14) and gastroesophageal reflux disease (GERD) (HR = 1.5, P = .18) trended toward higher conversion but were not significant. Of those with body mass index (BMI) >35 at time of conversion, the mean total body weight loss (TBWL) was 13.0% at the time of conversion. This subgroup had additional 13.6% of TBWL 1-year after conversion.

Conclusions: Conversion of LSG to RYGB increased with time to 12.6% conversion rate at 7-years. Patients with GERD prior to LSG had a nonsignificant trend toward conversion, while younger patients and females had significantly higher rates of conversion. There may be additional weight loss benefit for patients converted to RYGB.