Iron deficiency anemia after one anastomosis gastric bypass: A systematic review and meta-analysis

One anastomosis gastric bypass (OAGB) currently stands as the third most common metabolic and bariatric surgical procedure with increasing popularity worldwide. Iron deficiency anemia (IDA) is the most prevalent anemia observed after gastric bypass procedures. This systematic review and meta-analysis aimed to assess the overall incidence of IDA and identify the effect of biliopancreatic limb (BPL) length on the incidence of IDA in patients undergoing OAGB by a systematic literature search in PubMed, Web of Sciences, and Scopus. Twenty-six studies including 11,015 patients were finally included for review. The mean age and mean BPL lengths were 40.1 ± 7.2 years and 190.4 ± 29.2 cm respectively. The IDA prevalence after OAGB was 16% and BPL length was shown to predict IDA rates after OAGB (p = 0.042). Specifically, 8% of patients with a BPL length of 150-179 cm, 12% of patients with a BPL length of 180-199 cm, and 9% of patients with a BPL length of ≥ 200 cm experienced IDA. Despite the promising trends of performed OAGB worldwide, further studies are required to ascertain the risks related to this procedure and refine the surgical techniques.