The role of bariatric surgery in alleviating the impact of obesity on chronic digestive diseases

In this article, Dr. Daniel Hartmann, senior physician and specialist in visceral surgery at the Technical University of Munich and member of the UEG Public Affairs Committee, discusses the impact obesity can have on chronic digestive diseases and assesses why bariatric surgery may offer a key long-term solution in tackling this growing issue across Europe and the globe more widely.

The number of patients with obesity and their proportion of the population have been rising worldwide. The WHO claim that globally 1.3bn people are overweight and 600m people have obesity¹. Obesity rates have more than doubled in the last 40 years and are now in excess of 10% for both males and females.

Obesity is associated with an increased incidence of gastrointestinal cancer and the number of obese patients has been increasing in the field of gastroenterological surgery. Many of the leading causes of death and morbidity are chronic disorders, such as colorectal and pancreatic cancer, for which obesity can often be a key contributing factor. Therefore, we can confidently say that obesity is one of the most significant health challenges we face. Bariatric surgery can play an important role in the treatment of obesity and needs to be considered alongside conventional approaches.

The influence of obesity on gastroenterological surgery has been widely studied but few reports have focused on individual organs or surgical procedures. The evidence suggests that faster, sustained and long-term results for patients with obesity can be achieved via surgery². Bariatric surgery is the only treatment modality that produces continuous weight loss in patients with severe obesity. This has the potential to reduce all-cause mortality compared to obese patients not undergoing surgery and weight reduction, despite a relevant mental burden on patients with bariatric surgery that needs to be adequately addressed during follow-up³. More specifically, sustained weight loss via bariatric surgery has been shown to reduce the risk of cancer of any type by 78%⁴.

Weight loss is associated with a reduced risk of a number of metabolic comorbidities, including type 2 diabetes, increased blood pressure and non-alcoholic fatty liver diseases (NAFLD). Studies have also demonstrated that bariatric surgery leads to greater weight loss after the event, when compared with conventional therapy. Amongst the different types of surgical interventions, malabsorptive procedures have typically enhanced weight loss further in comparison with purely restrictive procedures.

Obesity can cause complications and technical challenges in colorectal, pancreatic and liver cancer surgical procedures, particularly in prolonging operative time⁵. Obesity will prolong hepatic resection operative time by approximately 50 minutes, with indications that resection time, blood loss, and rate of pulmonary complications all rise in patients with a BMI above 305. Performing bariatric surgery can help reduce these issues.

In relation to colorectal surgery specifically, while studies have suggested that obesity does not have a negative impact on mortality⁵, various studies have shown that obesity is a significant risk factor for complications and morbidity after surgery^6-7. This clearly supports the idea of reducing obesity wherever possible before colorectal surgery through bariatric surgery.

A reduction in obesity-related digestive diseases from bariatric surgery has broader benefits that need to be considered. If less patients are being diagnosed with conditions like colorectal, pancreatic and oesophageal cancer, it means less visits to their physicians and the hospital. This in turn helps reduce healthcare costs and the burden placed on healthcare systems, which is particularly important right now during the SARS-CoV-2 pandemic. One study has shown that the cost per 1 kg of weight loss following bariatric surgery is around 30% of the same weight loss through conventional means².

The obesity crisis in Europe is one of the most serious issues we currently face. There is a clear need for preventive and therapeutic measures and strategies at individual and public health level. Patients with severe obesity can particularly benefit from surgery as their first-line treatment, but this needs to be supported with structured behavioural therapies, dietary programmes and lifestyle changes to reduce calorie intake and increase exercise.

Professor Markus Peck, Chair of the UEG Public Affairs Committee, comments: “Obesity is placing an increasingly significant burden on healthcare systems across Europe and each day the mission to overcome this challenge grows greater. It is essential that we develop and deliver optimal prevention, treatment and care solutions to help tackle obesity and ensure European citizens can live healthy and enjoyable lives with increasing chances of active and healthy aging.”