Retrospective Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Oct 15, 2020; 11(10): 447-458
Published online Oct 15, 2020. doi: 10.4239/wjd.v11.i10.447
Risk of anemia in morbidly obese patients after bariatric surgery in Taiwan
Tse-Yao Wang, Hsien-Hao Huang, Ming-Shun Hsieh, Chih-Yen Chen
Tse-Yao Wang, Hsien-Hao Huang, Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei 112, Taiwan
Hsien-Hao Huang, Ming-Shun Hsieh, College of Medicine, National Yang-Ming University of Medicine, Taipei 112, Taiwan
Ming-Shun Hsieh, Department of Emergency Medicine, Taipei Veterans General Hospital, Taoyuan Branch, Taoyuan 330, Taiwan
Ming-Shun Hsieh, Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei 112, Taiwan
Chih-Yen Chen, Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei 112, Taiwan
Chih-Yen Chen, Faculty of Medicine and Institute of Emergency and Critical Medicine, National Yang-Ming University School of Medicine, Taipei 112, Taiwan
Chih-Yen Chen, Chinese Taipei Society for the Study of Obesity, Taipei 110, Taiwan
Author contributions: Hsieh MS and Chen CY contributed equally to this work and should be regarded as co-corresponding authors; Wang TY and Huang HH designed and performed the research and wrote the paper; Hsieh MS designed the research and contributed to the analysis; Chen CY designed the research and supervised the report.
Supported by the Yin Shu-Tien Foundation Taipei Veterans General Hospital-National Yang-Ming University Excellent Physician Scientists Cultivation Program, No. 107-V-B-087.
Institutional review board statement: This study was reviewed and approved by the Institutional Review Board of China Medical University (CMUH104-REC2-115).
Informed consent statement: Patients were not required to give informed consent to the study.
Conflict-of-interest statement: We have no financial relationships to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Chih-Yen Chen, AGAF, MD, PhD, Attending Doctor, Professor, Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, No. 201 Sec. 2, Shih-Pai Road, Taipei 112, Taiwan. chency@vghtpe.gov.tw
Received: April 30, 2020
Peer-review started: April 30, 2020
First decision: May 24, 2020
Revised: June 2, 2020
Accepted: September 8, 2020
Article in press: September 8, 2020
Published online: October 15, 2020
ARTICLE HIGHLIGHTS
Research background

Bariatric surgery is considered to be the most effective long-term treatment for morbidly obese patients. However, post-bariatric surgery anemia is identified as a common adverse effect and remains a challenge nowadays. This study revealed the long-term incidence of anemia in morbidly obese patients who received a bariatric procedure in large cohorts.

Research motivation

Although post-bariatric surgery anemia is identified as a common adverse effect, there are insufficient population-based cohort studies to demonstrate the long-term incidence of anemia and the risk of post-bariatric surgery anemia.

Research objectives

To estimate the risk of post-bariatric surgery anemia and to stratify the association between sex, age, and type of surgery.

Research methods

This study is a population-based cohort study. We conducted this nationwide study using claims data from National Health Insurance Research Database (NHIRD) in Taiwan. There were 4373 morbidly obese patients in this study cohort.

Research results

There were 4373 patients in the cohort. Among patients who were diagnosed with morbid obesity, 2864 received bariatric surgery. All obesity- and 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 sex, 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 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.

Research conclusions

We demonstrated the long-term incidence of post-bariatric surgery anemia and the risk of post-bariatric surgery anemia via a population-based cohort study in which data were obtained from the Taiwan NHIRD. Bariatric surgery increases the risk of anemia among obese patients, specifically in women, young- and middle-aged patients, and patients undergoing malabsorptive procedures. Malabsorptive procedures have a higher risk of anemia than restrictive procedures. Bariatric surgery increases the long-term risk of anemia. Considering the risk of post-bariatric surgery anemia, lifelong micronutrient supplementation was considered mandatory. Moreover, the quality and sustainability of medical follow-up consultation became an important consideration of bariatric surgery.

Research perspectives

A population-based database, like the Taiwan NHIRD, could provide the evidence of long-term risk. The data could also provide information for further analysis of the associated risks. A prospective cohort study or randomized trial could provide better statistical quality.