Risk of anemia in morbidly obese patients after bariatric surgery in Taiwan

BACKGROUND Bariatric surgery is one of most effective long-term treatments for morbid obesity.However,post-bariatric surgery anemia is identified as a common adverse effect and remains a challenge nowadays.AIM To estimate the risk of post-bariatric surgery anemia and to stratify the association between age,gender,and types of surgery.METHODS This study is a population-based cohort study.We conducted this nationwide study using claims data from National Health Insurance Research Database in Taiwan.There were 4373 morbidly obese patients in this study cohort.RESULTS Among patients who were diagnosed with morbid obesity,2864 received bariatric surgery.All obesity-associated comorbidities decreased in the surgical group.Increasing risk of post-bariatric surgery anemia among obese patients was found by Cox proportional hazards regression[adjusted hazard ratio(HR):2.36].Also,we found significantly increasing cumulative incidence rate of anemia among patients receiving bariatric surgery by log-rank test.After adjusting for age and gender,the increasing incidence of post-bariatric surgery anemia was found among women(adjusted HR:2.48),patients in the 20–29-year-old group(adjusted HR:3.83),and patients in the 30-64-year-old group(adjusted HR:2.37).Moreover,malabsorptive and restrictive procedures had significantly higher adjusted HRs,3.18 and 1.55,respectively.CONCLUSION Bariatric surgery give rise to anemia risk among obese patients,specifically in women,young-and middle-aged patients,and patients undergoing malabsorptive procedures in our population-based cohort study in Taiwan.