Bariatric surgery is indicated for patients with a body mass index (BMI) of 40 kg/m2 and higher
Based on a systematic review, bariatric surgery can also be considered for those with a BMI of 35 kg/m2 and higher and one or more comorbid diseases, such as hypertension, type 2 diabetes mellitus and obstructive sleep apnea. Some suggest considering bariatric surgery for those with recent-onset type 2 diabetes at a BMI of 30 kg/m2 and higher.1,2 Roux-en-Y gastric bypass and sleeve gastrectomy are the most common bariatric surgeries in Canada and are typically performed laparoscopically.
Bariatric surgery is the most effective means of sustained weight loss
Based on long-term clinical trial data, mean weight loss five years after gastric bypass was 23 kg, compared with 5 kg with medical treatment.2 Before surgery, patients are assessed by a comprehensive multidisciplinary team that evaluates and optimizes obesity-related comorbidities, both medical and psychosocial; looks for causes of obesity; and identifies patients who are not good candidates for bariatric surgery (e.g., who have severe and untreated psychiatric disease or a complex surgical history).
Bariatric surgery is associated with reductions in comorbidities such as diabetes, metabolic syndrome, obstructive sleep apnea and hypertension
Following bariatric surgery, about one-quarter of patients with type 2 diabetes achieve a glycosylated hemoglobin of less than 6% and decreased use of insulin and oral antihyperglycemic medications.2 Other benefits include reduced rates of hypertension, obstructive sleep apnea and dys-lipidemia at 3–5 years after surgical intervention.2,3
The risk of short-term complications varies
The risk of a major complication (obstruction, hemorrhage, venous thromboembolic event) in the first 30 days after surgery is about 5%, and depends on comorbidities, preoperative functional status, type of procedure being performed, and surgeon and hospital expertise.4 Short-term complications include bleeding, surgical-site infection, incisional and ventral hernia, and anastomotic leaks.2,4
Micronutrient deficiencies can occur after gastric bypass
The following investigations should be ordered within about four weeks after surgery (and in the months thereafter) to assess for micronutrient deficiencies: 24-hour urinary calcium, vitamin B12, folic acid, iron studies, 25-vitamin D, parathyroid hormone and vitamin A.5 Other tests (e.g., copper, zinc, selenium, thiamine) can be considered if patients have clinical signs or symptoms that suggest deficiencies.5
Footnotes
This article has been peer reviewed.
Competing interests: Timothy Jackson is a consultant at Health Quality Ontario. He performs bariatric surgery only in the public system. Michael Fralick receives funding from the Eliot Phillipson Clinician–Scientist Training Program at the University of Toronto, the Clinician Investigator Program at the University of Toronto, and from the Detweiler Travelling Fellowship, funded by the Royal College of Physicians and Surgeons of Canada. No other competing interests were declared.
References
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