eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2025-06-30 18 2 1176 1187 10.13005/bpj/3161 66164 article Ángel Tarra-Marrugo 1 Daniel Meléndez-Díaz 1 Yicela Pérez-Loaiza 1 Maryarena Castro-Leones 1 Leonardo Soto-Anaya 1 Dilia Aparicio-Marenco 2 Department of Medicine, Rafael Núñez University Corporation, Cartagena de Indias D.T. and C., Colombia. GINUMED, Department of Medicine, Rafael Núñez University Corporation, Cartagena de Indias D.T. and C., Colombia. Obesity is a chronic disease causing physical and mental health, leading to the rise of bariatric surgery as a treatment method. However, this increases the risk of nutritional deficiencies, including vitamin B1. Evaluate the pre- and post-surgical prevalence of vitamin B1 deficiency in bariatric surgery patients. A literature search was performed using EBSCO, PubMed, PubMed Central, ScienceDirect, Scopus, and Web of Sciences databases from 2014 to 2024. Three investigators independently selected publications and data were extracted into a matrix. A risk of bias assessment was performed using the CASP and Joanna Briggs Institute Checklist. Statistical analyses were conducted using R software. The review included 16 studies, of which 3,384 patients undergoing bariatric surgery were included and 2702 individuals with vitamin B1 deficiency. The prevalence of preoperative deficiency is 18%, and postoperative deficiency is 17% in 3 months, decreasing to 8% in 12 months.  The Roux-en-Y gastric bypass and sleeve gastrectomy showed postoperative prevalences of 12 and 4%, respectively. The most frequent comorbidities reported were DM-II, hypertension and dyslipidemias. Vitamin B1 deficiency associated with bariatric surgeries showed considerable pre-operative prevalence values, which decreased in the postoperative period due to strategies such as supplementation, favoring reduced adverse events and complications. https://biomedpharmajournal.org/vol18no2/prevalence-of-vitamin-b1-deficiency-associated-with-bariatric-surgery-in-obese-patients-systematic-review-and-mmeta-analysis/ Bariatric surgery Deficiency Obesity Prevalence Vitamin B1