Patients should lose weight before bariatric surgery

Lower BMI before bariatric surgery predicts greater post-operative weight loss, a new study from the University of Eastern Finland finds.

“Patients should definitely be encouraged to lose some weight already before their obesity surgery. This leads to a better weight management outcome in the future,” says Clinical Lecturer Pirjo Käkelä, Lic.Med., from the University of Eastern Finland, presenting the findings in her PhD thesis.

The study also found that small intestinal length is associated with serum triglyceride levels both before and after bariatric surgery. This means that it is possible to influence blood lipid levels by adjusting the length of the bypassed small intestine during obesity surgery.

Moreover, patients with gallbladder disease have lower serum plant sterol levels than others, and this is independent of post-operative weight loss, duration of gallbladder disease and non-alcoholic fatty liver disease.

“Because these factors did not play a role, the lower plant sterol levels in patients with gallbladder disease can probably be explained by their potentially inherited alterations in sterol absorption and biliary transport.”

The study is based on extensive data covering nearly 500 well-characterised bariatric patients who were recruited to the Kuopio Obesity Study (KOBS) in 2005–2015, as well as nearly 1,600 symptomatic gallstone patients who underwent laparoscopic cholecystectomy in a Finnish central hospital in 1995–2008. The bariatric procedure used was laparoscopic gastric bypass.

Increasing demand for bariatric surgery

Bariatric surgery is an excellent treatment for severely obese patients. In Finland, approximately 80% of all bariatric operations are laparoscopic gastric bypasses. It is estimated that at least 3,000 patients in Finland need bariatric surgery every year. However, the number of bariatric operations performed has stabilised at around 1,000 surgeries per year.

Gallstones can cause symptoms after bariatric surgery

The rising prevalence of gallstone disease in western countries has been associated with increasing prevalence of obesity and rapid weight loss induced by bariatric surgery. Furthermore, asymptomatic gallstones may become symptomatic and induce cholecystitis, and possibly lead to cholecystectomy.

Small intestinal length associates with triglycerides

The findings of the study suggest that small intestinal length is not associated with post-operative weight loss. However, small intestinal length is associated with serum triglyceride levels both before and after bariatric surgery. According to Clinical Lecturer Käkelä, this association with lipid metabolism suggests that it is worthwhile to measure the whole small intestinal length during the bariatric operation, which is something that isn’t routinely done.

“We suggest that the length of the total small intestine should be measured routinely during a bariatric operation, with special consideration given to the ratio of the bypassed lengths. This way, the outcomes of bariatric surgery could be even better with regard to comorbidities.”

Cholecystectomy is safe for obese patients

Lower BMI before bariatric surgery predicts greater post-operative weight loss. Obesity and comorbidities did not increase the risk of complications after cholecystectomy. However, in symptomatic gallbladder disease, comorbidities increased the prevalence of open surgery. Nevertheless, cholecystectomy was established as safe also for obese individuals.

Patients with gallbladder disease had the lowest serum plant sterol levels independent of post-operative weight loss, duration of gallbladder disease and non-alcoholic fatty liver disease, which suggests potentially inherited alterations in sterol absorption and biliary transport.

Genetic factors, together with environmental factors, are known to have an influence on weight regulation. However, the genetic risk score was not a predictor of post-operative weight loss.

The findings were originally reported in Surgical Laparoscopy Endoscopy & Percutaneous Techniques and in Obesity Surgery.