Iran Obesity and Metabolic Surgery (IOMS) Cohort Study: Rationale and Design


Obesity is a major global public health problem with a rapidly increasing prevalence. Bariatric surgery is the most effective treatment for morbid obesity and comorbidities that provides continuing weight loss for patients with severe obesity. The purpose of this cohort study is to create a suitable platform for developing evidence and assessing the health status of obese patients that can eventually promote the provision of health care and educational services to obese patients throughout the country. Iran Obesity and Metabolic Surgery is a prospective cohort study that started in 2008 and is ongoing. Laboratory tests and doctors’ visits are performed by a multidisciplinary team of experts in preoperative and postoperative follow-up at least up to 10 years post operation. A total of 19,730 patients entered the study from November 2008 to March 2018. Of these, 7922 patients were treated through surgery. Of those who underwent surgery, 80% were women and 36.2% were 30–40 years old. This cohort study responds to questions about the factors affecting the prognosis of patients, the survival of patients, the selection of an appropriate type of surgery for each case, the potential complications, the best follow-up times for the patients, and improvements in comorbidities. This study also seeks to create and expand collaboration through data linkage with other cohorts and registration centers and increase the use of the data existing in the databases. Based on the research findings, it is recommended to modify the bariatric surgery guidelines toward an evidence-based treatment approach for obesity.

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The authors would like to thank of all volunteers who have been paying for patients, physicians who worked without payment, researchers who worked voluntarily, and all patients who were referred to the clinic and collaborated to complete the database information. Special thanks are also given to Mr. Alireza Azarang, Dr. Sajedeh Riazi, and Dr. Somayeh Mokhber in setting up the cohort database and Rasoul Akram Clinical Research Development Center (RCRDC) and Dr. Bagherzadeh for the technical and editorial assists.


The Memorandum of Understanding to support the Obesity Surgery Registry was signed between the Deputy Director of Research and Technology of Ministry of Health and Medical Education (MOHME) and head of Minimally Invasive Surgery Research Center (MISRC) of Iran University of Medical Sciences (IUMS) on 20 April 2016. Before that, personal funds and charities supported the registry. Grants have been received from the MOHME, IUMS, and to allocate manpower, facilities (clinics and biobank), and physical space (Grant number 700/200).

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Correspondence to Maryam Hajian.

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Ethic approval

The medical ethics committee of IUMS confirmed this study (code: IR.IUMS.REC.1397.134).

Informed consent

All the patients sign a written informed consent to allow the use of their data. In addition, for each project, a separate more detailed written consent form approved by the Ethics Committee of each university that has a project is signed by all the patients.

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The authors declare no conflict of interest.

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Kabir, A., Pazouki, A. & Hajian, M. Iran Obesity and Metabolic Surgery (IOMS) Cohort Study: Rationale and Design. Indian J Surg (2021).

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  • Bariatric surgery
  • Metabolic surgery
  • Obesity
  • Overweight
  • Cohort