Fracture risk assessment and management should be part of weight loss care, according to Canadian researchers.
They found severely obese patients undergoing weight loss surgery were more likely to have increased fracture risks both before and after the surgical procedure.
Obesity may not be as protective for fracture as originally thought, said the study authors in the British Medical Journal.
As a result, they said guidelines should be followed on adherence to dietary supplements and physical activity, and patients should be referred to a specialist if fracture risk was considered high.
The benefits and risks of surgery should be considered on an individual basis to propose the type of surgical procedure best suited to the patient, as the efficacy of weight loss surgeries differs in terms of resolution of chronic conditions, they added.
The study examined the incidence and sites of fracture in severely obese patients who had undergone weight loss surgery, and compared them to obese and non-obese controls.
Data was analysed on 12,676 patients, and 38,028 obese and 126,760 non-obese controls between 2001-14.
Before surgery, 10.5% patients in the weight loss surgery group had at least one fracture, compared with 8.1% obese and 6.6% non-obese people in the control groups.
After a mean follow-up of 4.4 years, 4.1% of the weight loss surgery patients had at least one fracture, compared with 2.7% of obese and 2.4% of non-obese groups.
These increased fracture risks remained high even after adjusting for fracture history, number of comorbidities, material and social deprivation, and area of residence, said the study authors.
X-ray showing a femur, which sustained a fracture as a result of osteoporosis
They noted that the post-operative fracture risk changed from a pattern associated with obesity in the distal lower limb fracture, to a pattern typical of osteoporosis in the upper limb, clinical spine, pelvis, hip and femur.
The researchers suggested the increased fracture risk was due to falls and obesity related conditions, such as type 2 diabetes, as well as anatomical changes, and nutritional deficiencies induced by weight loss surgery.
They called for more research on preventative and therapeutic strategies to reduce the adverse effects of weight loss surgery on the bone, because of the “paucity of evidence based guidelines in this area.”
Marco Bueter, a bariatric surgeon at the University of Zurich, said the study represented “an important contribution to the evidence” on the management of patients after weight loss surgery.
Fracture risk assessment should be considered for all patients, as well as “following guidelines on nutritional supplementation that include the best available evidence”, he said in an editorial.