Bandlamudi, NandaHolt, GuyGraham, YitkaO'Kane, MarySinghal, RishiParmar, ChetanSakran, NasserMahawar, KamalPouwels, SjaakPotluri, SudhaMadhok, Brijesh2023-12-112023-12-112023-11-02Bandlamudi, N., Holt, G., Graham, Y., O'Kane, M., Singhal, R., Parmar, C., Sakran, N., Mahawar, K., Pouwels, S., Potluri, S., & Madhok, B. (2023). Malnutrition Following One-Anastomosis Gastric Bypass: a Systematic Review. Obesity surgery, 33(12), 4137–4146. https://doi.org/10.1007/s11695-023-06907-60960-89231708-042810.1007/s11695-023-06907-637917389http://hdl.handle.net/20.500.14200/3162Severe malnutrition following one-anastomosis gastric bypass (OAGB) remains a concern. Fifty studies involving 49,991 patients were included in this review. In-hospital treatment for severe malnutrition was needed for 0.9% (n = 446) of patients. Biliopancreatic limb (BPL) length was 150 cm in five (1.1%) patients, > 150 cm in 151 (33.9%), and not reported in 290 (65%) patients. OAGB was revised to normal anatomy in 126 (28.2%), sleeve gastrectomy in 46 (10.3%), Roux-en-Y gastric bypass in 41 (9.2%), and shortening of BPL length in 17 (3.8%) patients. One hundred fifty-one (33.8%) patients responded to treatment; ten (2.2%) did not respond and was not reported in 285 (63.9%) patients. Eight (0.02%) deaths were reported. Standardisation of the OAGB technique along with robust prospective data collection is required to understand this serious problem.en© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.GastroenterologySurgeryArticle