Introduction
Guidelines for preventing and treating osteoporosis resulting from bariatric surgery were provided in 2022 by the European Calcified Tissue Society (ECTS) (1) and the joint efforts of the Osteoporosis Research and Information Group (GRIO) and French Rheumatology Society (SFR) (2). A summary of these recommendations is provided in Table 1.
Screening
For patients aged 50 years and older, including post-menopausal women, the evaluation should include clinical risk factors, including a fracture history, alcohol consumption, and smoking habits, DXA testing of the lumbar spine and hip, spine radiographs or vertebral fracture assessment, measurement of bone turnover markers (BTMs), and biochemical analyses to identify secondary causes of osteoporosis. This assessment should ideally be performed before any bariatric surgery, regardless of the specific procedure (1,2). Some guidelines suggest that all patients undergoing Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion with duodenal switch (BPD/DS) should have their bone mineral density (BMD) and clinical risk factors evaluated due to the substantial bone loss and elevated fracture risk associated with these malabsorptive procedures (2). Moreover, patients considered at high risk should undergo these evaluations, regardless of age. High-risk status is determined by either experiencing a fragility fracture after age 40 years, having comorbidities, or taking medications linked to osteoporosis (e.g., corticosteroids, aromatase inhibitors) (2).
Non-pharmacological measures
Several studies have highlighted the positive effects of lifestyle changes in preventing bone loss; however, data on fracture outcomes are currently unavailable. It is generally accepted that following bariatric procedures, sufficient intake of calcium, vitamin D, and protein, along with regular exercise, is crucial to counteract the negative effects on bone and muscle (3,4) (Table 2).
Pharmacological intervention
Determining suitable standards for commencing anti-osteoporosis medications (AOM) is crucial to address and prevent bone fragility caused by bariatric surgery. Various societies have differing views on the specific treatment criteria for postmenopausal women and men aged ≥ 50 years, based on the occurrence of fragility fractures and/or T-score thresholds (1,2).
Most societies favor zoledronic acid (ZOL) as the primary option (5), because of issues with oral bisphosphonates intolerance and malabsorption. Owing to safety reasons and the potential risk of anastomotic ulceration and direct gastric irritation, oral bisphosphonates should be avoided after bariatric surgery. Denosumab is considered the secondary choice (6) when bisphosphonates are contraindicated or not tolerated, owing to its associated risks, particularly the potential for rebound effects upon discontinuation (7).
Information regarding the use of osteoanabolic agents for people living with obesity (PwO) after bariatric surgery is missing.
Nevertheless, the effectiveness of AOM in preventing bone loss following bariatric surgery remains partly unexplored, and there are currently no available data on fracture outcomes.
Conclusions
The field of skeletal health after bariatric surgery is evolving rapidly. Key concerns persist regarding who should undergo screening, how to conduct screening effectively, and when intervention is necessary. Clinicians should focus their attention on patients at high fracture risk, such as postmenopausal women and men older than 50 years. Before and after bariatric surgery, DXA should be used to measure BMD, and risk factors for osteoporosis should be assessed. Zoledronic acid as the first choice, together with appropriate vitamin D and calcium supplements, is preferred because of intolerance to oral bisphosphonate and malabsorption. Denosumab might be considered the secondary choice when ZOL is contraindicated or not tolerated. In patients at high risk of fracture, surgical interventions such as RYGB should be tailored to fracture risk, comorbidities, and desired weight loss.
The substantial metabolic changes triggered by glucagon like peptide 1 receptor agonists (GLP-1Ra) in PwO could potentially influence the fracture risk beyond its effects on BMD and BTMs (8). Moreover, it is crucial to gather more information on fracture-related outcomes associated with GLP-1Ra use.
Table 1: Summary of the main guidelines on the prevention and treatment of osteoporosis secondary to bariatric surgery
| Who to assess? | How to assess? | Who to treat? | How to treat? | |
| ASMBS (American Society for Metabolic and Bariatric Surgery) guidelines 2020 (9) | All women aged 65+ and men aged 70+ Postmenopausal women and men above age 50–69, based on the risk factor profileMen aged 50+ who have had an adult age fracture | Measurement of BMD by DXABone turnover markers (BTMs) can be considered | Not reported | General measures Calcium supplementation (1200–1500 mg/d after SG, AGB, and RYGB and 1800–2400 mg/d after BPD-DS) and attain a 25(OH) vitamin D concentration of at least 30 ng/mL. Increase of physical activity (aerobic and strength exercise) Anti-osteoporosis medication Not reported |
| ECTS (European Calcified Tissue Society) guidelines 2022 (1) | Menopausal women and men ≥ 50 years Pre-menopausal women and men < 50 years no routine BMD measurementBMD measurement in patients at high risk of fracture* | Measurement of BMD by DXA Spine radiographs or VFAClinical Osteoporosis risk factors (CRFs)FRAX®Bone turnover markers (BTMs) | Menopausal women and men ≥ 50 years: History of recent fragility fracture (> 40 years of age)T-score ≤ – 2 at the lumbar spine and/or femurFRAX® score with femoral neck BMD exceeding 20% for the 10-year MOF probability or exceeding 3% for hip fracture | General measures Treatment of vitamine D deficiency, optimization of total daily calcium and protein intakes as well as increase of physical activity (aerobic and strength exercise) Anti-osteoporosis medication Injectable bisphosphonates (zoledronate as first choice) Denosumab as second choice (contraindication or intolerance for bisphosphonates) |
| GRIO/SFR (Osteoporosis Research and Information Group – GRIO/ French Rheumatology Society – SFR) guidelines 2022 (2) | Menopausal women and men ≥ 50 yearsRegardless of age, in the case of RYGB and biliopancreatic diversion Regardless of age, for patients at high risk of fracture* | Measurement of BMD by DXA Vertebral imaging (if necessary)Clinical Osteoporosis risk factors (CRFs) | Menopausal women and men ≥ 50 years: If previous history of severe fracturesIf non-severe fracture and T-score ≤ -1If T-score ≤ -2 (in the absence of fractures) Who to refer? (to a specialist in bone diseases): Non-menopausal women and men < 50 years old If previous history of bone fragility fracturesif Z-score ≤ -2 (in the absence of fractures) | General measures Normalise the intake of calcium (1000 mg/day after SG, and 1500 mg/day after RYGB) and protein (at least 60 g/day); attain a 25(OH) vitamin D concentration of at least 30 ng/mL; prevent the risk of falls and introduce a program of weight-bearing physical activity Anti-osteoporosis medication Zoledronic acid (cycle of 3 perfusions) No evidence supporting the benefit of using denosumab or oral bisphosphonates |
SG: sleeve gastrectomy; RYGB: Roux-en-Y gastric bypass; DBP: biliopancreatic diversion; BMD: bone mineral density; VFA: vertebral fracture assessment
* Patients at high risk of fracture are:
– those with a history of fragility fracture after the age of 40;
– those presenting comorbidities that are frequently associated with osteoporosis, i.e. certain endocrinopathies, neurological disorders with neurosensory impairment, hepatic cirrhosis, chronic obstructive pulmonary disease > stage 1, and chronic inflammatory diseases);
– those taking medications that are frequently associated with osteoporosis (corticosteroids, LH-RH antagonists, antiretroviral drugs, aromatase inhibitors, prolonged chemotherapy).
Table 2: Non-pharmacological prevention and treatment of bone health impairment in all Bariatric Surgery-treated patients
| Rules to follow |
| – Adequate calcium intake (at least 1200 mg/day) |
| – Normalize the intake of protein (at least 60 g/day) – use of protein powder if needed |
| – Vitamin D ideally per day (at least 2000 units/day) throughout the year (attain a 25(OH) vitamin D concentration of 30–60 ng/mL) |
| – Prevention of falls |
| – Promote weight-bearing physical activity and progressive resistance training program |
| – No smoking |
| – Limited alcohol intake |
Prof. Julien Paccou Professor of Rheumatology Rheumatology Department, Lille University Hospital, France
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