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[11 min read] Managing bariatric surgery patients in primary care
Obesity rates in Australia are high with nearly two thirds of adults being classified as obese. Obesity is associated with several comorbidities including type 2 diabetes, hypertension, obstructive sleep apnoea, and osteoarthritis, and is consequently linked with increased cardiovascular morbidity and mortality, cancer, functional impairment, and premature death.
Bariatric surgery is the most effective method for substantial and sustained weight loss, with a significant reduction in obesity-related comorbidities and long-term mortality. As such, general practitioners are seeing an increasing number of patients with severe obesity who wish to be referred for bariatric surgery.
The role of GPs
GPs play a pivotal role in the management of obesity with early referral of motivated patients who have failed to lose weight. Given the high level of psychosocial disorders in this patient group, it is also important for GPs to provide support where appropriate.
Prior to referral for bariatric surgery, patients need to be made aware of the risks and benefits, including the requirement for lifelong follow-up.
The laparoscopic adjustable gastric band (LAGB) is a restrictive procedure which artificially creates a small pouch with a narrow outlet. The sleeve gastrectomy (SG) is a restrictive procedure whereby the stomach volume is reduced in size. The Roux-en-Y gastric bypass (RYGB) is both a restrictive and malabsorptive procedure making up more than half of all bariatric procedures and is associated with the greatest excess weight loss.
Once a referral has been made to bariatric multidisciplinary teams, it is important that dietetic support continues from the GP, as any deviation such as weight gain can result in surgery being denied or temporarily withdrawn for the patient.
Bariatric units should provide clear guidance on the diet to be followed after discharge, including requirements for multivitamins and lifestyle modification. Bariatric surgeons usually follow up patients for two years after surgery, after which the transfer of care will be to primary care.
The short-term complications of bariatric surgery include wound infections, vomiting, intolerance to puréed meals, dysphagia, and an anastomotic/staple line leak. Clinical signs in this early stage may be subtle and the GP should urgently refer back to their local bariatric unit.
Bariatric patients can develop many problems long-term which may require attention from their GP. Dehydration and hair loss can occur frequently, as well as dumping syndrome, obstruction, reflux, gastric dysmotility, internal hernias, vomiting, over-restriction, and ulceration.
All bariatric procedures lead to a reduced calorie intake. The RYGB carries the greatest risk of nutritional deficiencies. Most patients have established a balanced diet after two years. but issues may still arise.
Protein-calorie malnutrition, the most severe macronutrient complication, can be avoided by ingesting a diet rich in protein with carbohydrates and fat added as determined by energy needs. However, micronutrient deficiencies are more common after surgery. These include deficiencies in iron, vitamin B12, thiamine, folate, and vitamin B6. Secondary hyperparathyroidism with bone demineralisation may occur following surgery, so lifestyle modification and supplementation is necessary following surgery.
GPs play a key role in ensuring compliance with multivitamin supplementation, which is often neglected by patients years after surgery. Annual monitoring is recommended and should at a minimum include a full blood count, electrolytes, liver function tests, and serum levels of glucose, iron, ferritin, vitamins D, B12, calcium, parathyroid hormone, thiamine, folate, and selenium.
Chronic diseases following bariatric surgery
Bariatric surgery can result in remission of a number of obesity-related comorbidities. Remission of type 2 diabetes has been demonstrated. Effects on hypertension, hyperlipidaemia, and obstructive sleep apnoea are also evident, and patients should be periodically evaluated.
Pregnancy following bariatric surgery
Female patients may find it easier to conceive post-surgery, but should avoid doing so for 12-18 months because of rapid weight loss and nutritional deficiencies. Perinatal outcomes following bariatric surgery include an increased risk of preterm births, so GPs need to develop a contraceptive strategy.
Weight loss and regain
Patients need a realistic expectation of excess weight loss. The goal is not an ‘ideal weight’, but a ‘healthy weight’. Excess weight loss at one year can be as high as 57.8 per cent with patients plateauing after two years. GPs play a crucial role in ensuring compliance with dietary and lifestyle recommendations. Weight regain is not uncommon.
To conclude, the role of the GP is crucial in guiding patients before and after bariatric surgery. GPs may be the only medical professionals involved years after surgery is performed and it is essential that long-term surveillance is continued.
Want to learn more about managing your patients’ nutrition concerns in general practice? Upskill in Medical Nutrition Management.