Long-term Mortality Trends in Four Bariatric Surgery Procedures

Among US adults, the prevalence of severe obesity (body mass index [BMI] ≥ 40 kg/m2) doubled from 1999-2000 (4.7%) to 2017-2018 (9.2% ) in the National Health and Nutrition Examination Survey (NHANES). Population studies have observed that patients with severe obesity have a higher risk of cardiometabolic diseases and mortality].

Although bariatric surgery is the most successful treatment for the severely obese population, it remains underutilized. Patients who have undergone bariatric surgery have demonstrated significant improvement in obesity-related comorbidity, such as remission of type 2 diabetes mellitus and decreased long-term mortality compared to nonsurgical patients with severe obesity. , stimulating great interest in the discovery of causal pathophysiological mechanisms that may facilitate non-surgical treatment of obesity.

This retrospective study compared the long-term mortality of bariatric surgery patients and matched nonsurgical participants identified from driver’s licenses. While mortality after gastric bypass surgery was previously reported from 1984 to 2002, this study extends mortality follow-up through 2021. Additional patients with gastric bypass and patients who underwent gastric banding, sleeve gastrectomy, or duodenal switch from 1982 to 2018 have been included. Mortality results were also analyzed stratified by sex, types of bariatric surgeries, and patients’ ages at the time of surgery.

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New retrospective study with up to 40 years of follow-up shows significant reductions in mortality rates from all causes and cause-specific conditions such as cardiovascular disease, diabetes and cancer in patients who have undergone bariatric surgery compared to participants who have not with severe obesity, according to a new study published in Obesity , the flagship journal of The Obesity Society (TOS).

Younger population experiences higher risk of death from suicide, chronic liver disease

The study also found evidence suggesting an increased risk of death from chronic liver disease, as well as higher rates of death from suicide in younger patients who underwent bariatric surgery compared to non-surgical participants. The study authors note that findings of higher suicide rates among younger patients who have undergone bariatric surgery may encourage more aggressive presurgical psychological evaluation and post-surgery follow-up.

As a result of bariatric surgery’s decades-long durability in reducing deaths from all causes and decreasing deaths related to cardiovascular disease, diabetes and cancer compared with matched participants, the researchers note that the findings may not will only increase interest in bariatric surgery treatment for severely obese patients but will further stimulate important research related to the discovery of physiological and biomolecular mechanisms leading to non-surgical treatments that result in weight loss and improved mortality similar to that achieved by bariatric surgery, said Ted D. Adams, Intermountain Surgical Clinical Specialty Program/Digestive Health, Intermountain Healthcare, Salt Lake City, Utah; Division of Epidemiology, Department of Internal Medicine, School of Medicine and Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City. Adams is the corresponding author of the study.

Experts explain that multiple association studies connecting bariatric surgery and mortality outcomes have been reported, predominantly retrospective, with wide variation in study design related to number of participants, control cohorts, mean follow-up, type of procedure, age at surgery, clinical endpoints such as life expectancy and all-cause and cause-specific mortality rates, and the presence or absence of prevalent diabetes. The new study builds on the groups’ reported mortality outcomes after gastric bypass surgery by extending follow-up to 40 years, tripling the number of surgical patients, and using four, rather than one, bariatric surgery procedures.

The researchers used data from the Utah Population Database (UPDB) for the current study. The UPDB includes linked Utah population-based information to statewide birth and death certificates, driver’s licenses and identification cards, and voter registration cards. The UPDB creates and maintains links between the database and the medical records of Utah’s two largest healthcare providers.

Patients who had undergone bariatric surgery in Utah between 1982 and 2018 were identified from three large bariatric surgical practices in Salt Lake City, Utah, and from medical records at the University of Utah and corporate data warehouses at Intermountain Healthcare in Salt Lake City. Nonsurgical participants were recruited from Utah driver’s license or identification card records. Because driver’s licenses are typically renewed every five years, multiple registries were available for bariatric surgery match selection.

Nearly 22,000 participants with and without bariatric surgery were matched (1:1) for age, sex, body mass index, and surgery date to driver’s license/renewal date. Mortality rates were compared using Cox regression and stratified by sex, type of surgery, and age at surgery. While mortality after gastric bypass surgery was previously reported between 1984 and 2002, this study extends mortality follow-up through 2021. The four bariatric surgery procedures included Roux-en-Y gastric bypass, adjustable gastric banding, gastric bypass sleeve and biliopancreatic diversion with duo-rejection switch.

Results revealed that all-cause mortality was 16% lower in patients who underwent bariatric surgery compared to nonsurgical participants.

Lower mortality was observed for both males and females. Mortality after surgery versus no surgery decreased by 29%, 43%, and 72% for cardiovascular disease, cancer, and diabetes, respectively. Mortality rates for men and women from chronic liver disease were 83% higher in patients who underwent surgery compared with nonsurgical participants. The hazard ratio for suicide was 2.4 times higher in participants with surgery compared to participants without surgery, primarily in people aged 18 to 34 years at the time of surgery.

“This important study adds to the growing evidence that bariatric surgery not only improves patients’ quality of life, but will also increase their life expectancy. This work will hopefully improve patient access to this effective obesity treatment, which is still limited to only one percent of qualified patients.Additionally, the study highlights the importance of providing more resources for pre-surgical psychological evaluation and post-surgery follow-up, especially for younger patients,” said Jihad Kudsi, MD, MBA, MSF, DABOM, FASMBS, FACS, Division of Bariatric Surgery, Duly Health and Care, Downers Grove, Ill. Kudsi was not associated with the investigation.

Importance of the study

What is already known?

• Multiple retrospective studies and one prospective study (Swedish Obesity Subjects Study) reported lower all-cause mortality among patients who underwent bariatric surgery compared with BMI-matched patients who did not undergo bariatric surgery. In addition to reduced all-cause mortality, studies have reported reduced mortality rates related to cardiovascular disease, cancer, and diabetes among bariatric surgery patients compared to non-surgery patients.
   
• Our group has previously reported long-term mortality of Roux-en-Y gastric bypass patients compared to participants with BMI identified from driver’s licenses. This previous study was limited to only gastric bypass patients (approximately 7000), and follow-up was only until 2002.

What does this study add?

• The current study extends follow-up up to 40 years and includes nearly 22,000 surgical patients representing the four main types of bariatric procedures performed today.
   
• Lower all-cause mortality was reported for male bariatric surgery patients, as well as female patients, compared with non-surgical participants of the same sex.

How might these results change the direction of research or the focus of clinical practice?

• The reported findings of higher suicide rates among bariatric surgery patients who underwent surgery at younger ages (i.e., 18-34 years) may result in more aggressive presurgical psychological evaluation and post-surgery follow-up, especially among patients representing this age group.
   
• As a result of bariatric surgery’s decades-long durability in reducing all-cause death and reducing deaths related to cardiovascular disease, cancer, and diabetes compared to matched participants with severe obesity, these findings may not only increase interest in bariatric surgery treatment for patients with severe obesity, but in addition, will further stimulate important research related to the discovery of physiological and biomolecular mechanisms leading to non-surgical treatment resulting in weight loss and improved mortality similar to that achieved with bariatric surgery.