Anemia rates after one-anastomosis gastric bypass versus sleeve gastrectomy: a retrospective cohort study

Purpose: To compare postoperative anemia rates after one-anastomosis gastric bypass (OAGB) with those after sleeve gastrectomy (SG) in a large nationwide, population-based cohort study.

Methods: We sourced data from the Israeli Bariatric Surgery Registry. The study included a cohort of adults who underwent bariatric surgery (BS) between 2013 and 2017. Hemoglobin (Hb) was measured preoperatively and then 1 and 2 years post-BS. Anemia rates were compared between the patients who underwent OAGB and those who underwent SG, using multivariable analyses.

Results: The study comprised 1,052 patients who underwent OAGB and 5,885 patients who underwent SG. Among them, 24.1% and 23.6% were men, respectively, and the preoperative mean body mass index values were 41.7 ± 5.0 and 42.1 ± 5.1 kg/m2, respectively. The 1-year and 2-year postoperative anemia rates were significantly higher after OAGB than after SG, when adjusted for age, pre-surgery BMI, sex and other covariates (1 year: 37.5% vs. 20.2%; adj-OR = 2.43; 95% CI 2.08-2.86; 2 years: 45.1% vs. 28.5%; adj-OR = 1.92; 95% CI 1.59-2.32).

Conclusions: Patients who underwent OAGB had significantly higher anemia rates 1 year and 2 years postoperatively than those who underwent SG. Consequently, vigilant surveillance and intervention strategies post-OAGB should be considered to mitigate the incidence of anemia and its associated complications.