# Understanding Weight Loss Surgery Worldwide: A Patient's Guide to the 2022 IFSO Global Registry Report Weight loss (bariatric) surgery is remarkably safe and is being performed on a large scale worldwide, according to a major 2022 international report. The Seventh IFSO Global Registry Report analyzed **311,441 operations** performed across 25 national and regional registries, and found that sleeve gastrectomy is the most common procedure, type 2 diabetes is the most frequent obesity-related disease among surgical patients, and the reported death rate following surgery was just **0% to 0.11%**. The report marks a shift toward more reliable, aggregated data collection from established registries, giving patients and doctors a clearer picture of global practice. # Understanding Weight Loss Surgery Worldwide: A Patient's Guide to the 2022 IFSO Global Registry Report ## Table of Contents - Key Points - Background: Why This Report Matters - Study Methods: How the Data Was Collected - Key Finding 1: Who Is Having Weight Loss Surgery? - Key Finding 2: What Operations Are Being Performed? - Key Finding 3: Obesity-Related Diseases in Surgical Patients - Key Finding 4: How Safe Is Weight Loss Surgery? - Clinical Implications: What This Means for Patients - Limitations: What This Report Couldn't Prove - Recommendations: What Should Happen Next? - Frequently Asked Questions - Source Information ## Key Points - The 2022 IFSO Global Registry Report analyzed 311,441 operations from 25 national and regional registries worldwide. - Reported death rates after weight loss surgery were 0% to 0.11%, comparable to other common elective surgeries. - Sleeve gastrectomy is the most common primary procedure; type 2 diabetes is the most frequent comorbidity. - Across all registries, most patients were female, with median starting BMI typically 40-45 kg/m². - The report is descriptive, not experimental, and cannot prove long-term outcomes or why gender differences in comorbidities exist. ## Background: Why This Report Matters The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) is a global organization representing surgeons and health professionals who treat obesity. Its stated mission is simple but ambitious: **"to aspire to provide the most credible and transparent information available on bariatric/metabolic surgery."** This report is the seventh edition of its global registry series, released in August 2022. What exactly is a registry? According to the Agency for Healthcare Research and Quality, a registry is an organized system that uses observational methods to collect uniform data — clinical and other — to evaluate specific outcomes for a population defined by a particular disease or condition. When data is collected reliably and prospectively, it gives researchers a unique opportunity to understand patterns of disease and the real-world effects of treatments. The history of this registry shows how far the field has come. The first IFSO Global Registry Report was produced in 2014, drawing on contributions from **18 countries across 5 continents, with 100,092 operation records** — of which 53,197 were performed in the calendar years 2011–2013. In that first report, contributions varied enormously: one individual centre entered just 24 operation records, while two countries with established national registries (Sweden and the United Kingdom) each contributed over 34,000 records. By the sixth report, the registry had grown to **507,298 operations from 50 contributor countries and 5 national registries**. However, the project faced significant obstacles. These included a lack of consistent definitions for data fields (making true comparisons between countries difficult), and the fact that some countries were represented by a single surgical centre, which meant the data did not accurately reflect the entire country's activity. The introduction of the General Data Protection Regulation (GDPR) in Europe in May 2018 also changed how individual patient data could be collected and shared, placing new responsibilities on IFSO as the data controller. ## Study Methods: How the Data Was Collected This seventh report represents a fundamental change in approach. Unlike the first six reports, which were based on individual-level patient data, this report contains **only aggregated data** from established national or regional bariatric surgery registries. No individual patient data was collected. IFSO knew of **32 national or regional registries** worldwide. Of these, **25 agreed to participate — 23 national registries and 2 regional registries** (Ontario in Canada and Michigan in the United States). This means that **78.1% of all known registries** are represented in the report. The operations included were performed in either **2020 (for the USA) or 2021 (for the rest of the world)**. The data collection team at the Australia and New Zealand Bariatric Surgery Registry (ANZBSR) — Jennifer Holland, Angus Campbell, Robin Thompson, Jenifer Cottrell, and Dianne Brown — created a data dictionary, built a secure REDCap database housed at Monash University in Melbourne, Australia, and collected the aggregated data from each registry. The Data Vision Lab in the Netherlands then performed the analysis and created the visualizations. The datasets focused on three key areas: the **demographics** of people undergoing weight loss surgery, the **types of procedures** being performed, and markers of **perioperative safety** (outcomes around the time of surgery, such as length of hospital stay, readmissions, and deaths). Because each registry already collected data according to its own definitions, it was not possible to perfectly align every dataset — where important definitional differences existed, they are flagged in the report. Important caveats remain even with this improved structure. Very few registries achieve complete data ascertainment, meaning not 100% of people who undergo bariatric procedures are included in their registry. Not all registries have complete follow-up in the perioperative period, so some complications may not have been recorded. Registries also differ in how they audit or confirm data accuracy. These limitations are important to keep in mind when reading the results. ## Key Finding 1: Who Is Having Weight Loss Surgery? The report looked closely at the age, sex, and body mass index (BMI) of patients undergoing weight loss surgery. BMI is a measure of body fat based on height and weight; a BMI of 30 or higher indicates obesity, and a BMI of 40 or higher indicates severe (or "morbid") obesity. One finding was consistent across every single reporting registry: **the majority of patients were female**. This pattern held true in all countries and regions, reflecting a well-known global trend in who seeks out weight loss surgery. The **median starting BMI** of patients varied significantly by country. The lowest median starting BMI was **36.8 kg/m² in China**, followed by **54.1 kg/m² in Azerbaijan** at the other end of the spectrum. The majority of registries reported starting BMIs in the **40–45 kg/m² range**, which is firmly in the severe obesity category. Age also varied. The median patient age was just **25 years in Kuwait and 32 years in China**, compared to **44 years in the Netherlands, Italy, and New Zealand**. This wide range suggests that different countries have different patterns of when patients pursue surgery — some earlier in life, others later. ## Key Finding 2: What Operations Are Being Performed? The report catalogued the types of weight loss operations being performed worldwide, distinguishing between **primary procedures** (a first-time weight loss surgery) and **revisional procedures** (a second surgery to correct or revise a previous one). The most common procedure across all registries was **sleeve gastrectomy** — a procedure in which roughly 80% of the stomach is removed, leaving a banana-shaped tube. The second most common was **Roux-en-Y gastric bypass**, which creates a small stomach pouch and reroutes part of the small intestine. These two operations form the backbone of modern bariatric surgery. The report also noted an increasing number of **"other" procedures** — including operations like the single-anastomosis (one-anastomosis) gastric bypass — particularly in the revisional setting. This suggests that surgeons are expanding their toolkit for patients who need a second operation after an initial procedure. In terms of surgical technique, the **majority of operations were performed laparoscopically** — meaning through small "keyhole" incisions rather than one large open incision. However, the report highlighted that the uptake of **robotic surgery continues to increase**, especially for revisional procedures. Robotic surgery uses computer-assisted instruments that give the surgeon enhanced precision and control. ## Key Finding 3: Obesity-Related Diseases in Surgical Patients Obesity is rarely an isolated condition — it is often accompanied by other chronic diseases, known as **comorbidities** (diseases that occur at the same time as another condition). The report examined which obesity-related diseases were most common among patients undergoing weight loss surgery. The most frequently reported preoperative comorbidity was **type II diabetes**. The highest rates of type II diabetes among people undergoing bariatric surgery were seen in **Michigan (USA)**, while the lowest rates were reported in **Italy**. A particularly interesting finding concerned **gender differences** in coexisting diseases. Males were more likely than females to report having: - **Diabetes** (high blood sugar that can damage organs over time) - **Obstructive sleep apnea (OSA)** — a condition where breathing repeatedly stops and starts during sleep - **Dyslipidemia** — abnormal levels of fats (cholesterol) in the blood - **Hypertension** — high blood pressure Females, on the other hand, were **more likely to report depression**. The researchers noted that these differences were **consistent between countries**, making them "worthy of further investigation." These patterns may reflect underlying biological differences, differences in how men and women are screened or diagnosed, or social and psychological factors surrounding obesity and its treatment. ## Key Finding 4: How Safe Is Weight Loss Surgery? For patients considering weight loss surgery, safety is naturally a top concern. This report brings reassuring news: **bariatric metabolic surgery is very safe**. The **reported death rate** following surgery across all registries was **0% to 0.11%** — meaning at most roughly 1 death per 1,000 operations, and in many registries zero deaths. For context, this is comparable to or better than the risk of many other common elective surgeries. The report also looked at **length of hospital stay**, which varied considerably between countries. For primary procedures, the median length of stay ranged from just **1 day in Ontario (Canada), the Netherlands, Sweden, Norway, and Michigan (USA)** to **6 days in China**. The researchers noted that these differences probably reflect **cultural expectations around discharge timing** and the availability of community resources — not necessarily differences in medical need or quality of care. In other words, a shorter hospital stay in one country does not mean patients there are healthier or receiving worse care; it may simply reflect different norms about recovery at home. Two other patterns emerged regarding hospital stays: - Most countries reported a length of stay that was **slightly higher for revisional procedures** than for primary procedures — likely because revisional operations are more complex and involve scar tissue from the previous surgery. - The rates of **unplanned readmission** (being admitted back to the hospital after being discharged) were **slightly higher in those registries with the shortest length of stay** — a finding that makes intuitive sense, since patients going home sooner have less time to be monitored in a hospital setting. ## Clinical Implications: What This Means for Patients So what does this report mean for someone considering weight loss surgery — or for someone who has already undergone a procedure? **First, it confirms that weight loss surgery is a very safe option for treating severe obesity.** The 0–0.11% mortality rate is an important number for patients and their families to understand when weighing the risks of surgery against the very real risks of untreated severe obesity, which include heart disease, stroke, diabetes complications, and certain cancers. **Second, the report provides a detailed picture of the "typical" bariatric surgery patient.** The typical patient is female, has a starting BMI of roughly 40–45 kg/m², and is between the age of 25 and 44 depending on the country. However, the wide ranges show that weight loss surgery is being used successfully across a broad spectrum of ages and body sizes. **Third, the findings suggest that surgeons are increasingly tailoring procedures to individual patients.** The growing variety of procedures — including "other" and revisional operations — means that patients who have not succeeded with one approach may have additional options. The increasing use of robotic techniques also reflects ongoing innovation in the field. Finally, the gender differences in coexisting diseases highlight the importance of **comprehensive preoperative screening**. Male patients should be carefully evaluated for diabetes, sleep apnea, abnormal cholesterol, and high blood pressure, while female patients should be screened for depression. This personalized approach to preparing for surgery can improve outcomes for everyone. ## Limitations: What This Report Couldn't Prove It is just as important to understand what this report cannot tell us as what it can. The authors themselves acknowledge several key limitations: - **Not every patient is included.** Very few registries capture 100% of the weight loss surgeries performed in their region. The data may therefore not represent everyone having surgery. - **Incomplete follow-up.** Not all registries have complete follow-up in the perioperative period (the time immediately before, during, and after surgery), meaning some complications may not have been recorded. - **Differences in definitions.** Each registry has its own definitions for data items. Where these differences were major, they are flagged — but they still limit how directly different countries can be compared. - **Different auditing practices.** Registries differ in how they verify that their data is accurate, which means confidence in data quality varies from registry to registry. - **Incomplete data items.** Not all countries/regions collected all of the data items chosen for the global report, so for some outcomes, the analysis is based on a subset of registries. This report is also **descriptive rather than experimental**. It describes what is happening in bariatric surgery worldwide, but it does not compare surgery against non-surgical treatments, nor does it track long-term outcomes like weight loss durability or resolution of diabetes years after surgery. It also does not explain *why* gender differences in coexisting diseases exist — it simply documents them as consistent findings that warrant further research. ## Recommendations: What Should Happen Next? The report's authors are clear that this is a work in progress. While this seventh report represents a major step forward in data quality, it also lays out a roadmap for the future of global monitoring of weight loss surgery. **Expanding registry coverage.** IFSO currently has **72 official member societies**, and IFSO is aware that **32 societies run a national registry**. Of those, 25 contributed to this report. The goal is to eventually include national registry data from **every member society**, so that data reflects all bariatric surgery performed worldwide. IFSO hopes that other established registries will contribute to the next report, and encourages countries that are building their bariatric programs to set up national registries from the start. **Standardizing data collection.** In collaboration with **Bristol University**, IFSO has supported the development of a **minimum dataset** for national bariatric registries. This will support a common data dictionary — a shared set of definitions — so that future reports can compare "like with like." The common data dictionary will be the basis for a **REDCap database** that can be shared with member societies, along with mentorship and support through the required legal and regulatory processes. **For patients,** the key takeaway is straightforward: seek care at a program that participates in a national or regional registry. Registry participation is a marker of a commitment to quality assurance, transparency, and continuous improvement. It means the program is tracking its outcomes and comparing them against national and international benchmarks. With these efforts, the IFSO Global Registry is working toward its goal of providing the most credible and transparent information available on bariatric and metabolic surgery — ultimately helping to optimize care for people living with obesity, a condition the registry authors describe as **adiposity-based chronic disease**. ## Frequently Asked Questions ### How safe is weight loss surgery? A major 2022 international report analyzing over 311,000 operations found the death rate within 30 days after bariatric surgery ranged from 0% to 0.11%, meaning at most roughly one death per 1,000 operations. This is comparable to or better than many other common elective surgeries, making weight loss surgery remarkably safe. ### Who typically undergoes weight loss surgery? Worldwide, the majority of patients having weight loss surgery are female. Median starting BMI is usually 40-45 kg/m², which falls in the severe obesity range. Patient age varies notably by country, from a median of 25 years in Kuwait to 44 years in the Netherlands, Italy, and New Zealand. ### What is the most common weight loss operation? Sleeve gastrectomy is the most frequently performed primary weight loss procedure worldwide, followed by Roux-en-Y gastric bypass. These two operations are the backbone of modern bariatric surgery. Surgeons are also increasingly using other procedures, especially for revisional surgeries, and robotic techniques are becoming more common. ### Which obesity-related diseases are most common in surgery patients? Type 2 diabetes is the most frequently reported obesity-related disease among patients undergoing weight loss surgery. Males are more likely to have diabetes, obstructive sleep apnea, dyslipidemia, and hypertension, while females are more likely to report depression. These differences were consistent across countries and warrant further investigation. ### How long is the hospital stay after weight loss surgery? The median hospital stay varies by country, ranging from 1 day in several countries including Canada, the Netherlands, Sweden, and Norway, to 6 days in China. Shorter stays likely reflect different cultural norms and resources, not worse care. Revisional procedures tend to have slightly longer stays than primary procedures. ### What is the difference between primary and revisional weight loss surgery? Primary surgery is a patient's first weight loss operation, while revisional surgery is a second operation to correct or revise a previous one. Revisional procedures are often more complex because they involve scar tissue, which is why hospital stays tend to be slightly longer for these cases. ### Why does it matter if a weight loss program participates in a registry? Registry participation shows a program is committed to quality assurance and transparency. It means the program tracks its outcomes and compares them to national and international benchmarks. For patients, seeking care at a program that participates in a national or regional registry can be a marker of continuous quality improvement. ## Source Information **Original article:** Seventh IFSO Global Registry Report 2022 **Authors/Contributors:** Wendy A. Brown MBBS (Hons) PhD FACS FRACS, Scott Shikora MD FACS FASMBS, Ronald Liem MD, Jennifer Holland BSpPath MHlthInfoMgmt CHIA, Angus Brian Campbell BS, Sara Maria Sprinkhuizen PhD, Sonja Kuijpers BA, Lilian Kow BMBS PhD FRACS. **Publisher:** The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO), August 2022. **Note:** This patient-friendly article is based on peer-reviewed research from the IFSO Global Registry Report, prepared with support from the Australia and New Zealand Bariatric Surgery Registry (ANZBSR) and the Data Vision Lab (Netherlands). --- Publisher: Diagnostic Detectives Network (https://diagnosticdetectives.com) — independent multi-expert medical second opinions, worldwide, private-pay. Author byline: Anton Titov, MD, PhD. Contact: https://diagnosticdetectives.com/pages/contact Canonical page: https://diagnosticdetectives.com/products/understanding-weight-loss-surgery-worldwide-a-patients-guide-to-the-2022-ifso-global-registry-report