Risedronate to Prevent Bone Loss After Sleeve Gastrectomy: Study Design and Feasibility Report of a Pilot Randomized Controlled Trial

Strategies to reduce the onset of sleeve gastrectomy associated bone loss (STRONG BONES): Trial design and methods

Background

Despite recognized improvements in obesity-related comorbidities, mounting evidence implicates surgical weight loss in the onset of skeletal fragility. Sleeve gastrectomy (SG) is the most commonly performed bariatric procedure and is associated with 3-7% axial bone loss in the year following surgery. Bisphosphonates are FDA-approved medications for the prevention and treatment of age-related bone loss and may represent a strategy to reduce bone loss following SG surgery.

Methods

The Strategies to Reduce the Onset of Sleeve Gastrectomy Associated Bone Loss (STRONG BONES) trial (NCT04922333) is designed to definitively test whether monthly administration of the bisphosphonate, risedronate, for six months can effectively counter SG-associated bone loss. Approximately 120 middle-aged and older (≥40 years) SG patients will be randomized to six months of risedronate or placebo treatment, with skeletal outcomes assessed at baseline, six, and 12-months post-surgery. The primary outcome of the trial is 12-month change in total hip areal bone mineral density (aBMD), measured by dual energy x-ray absorptiometry (DXA). This will be complemented by DXA-acquired aBMD assessment at other skeletal sites and quantitative computed tomography (QCT) derived changes in bone quality. Change in muscle mass and function will also be assessed, as well as biomarkers of bone health, turnover, and crosstalk, providing mechanistic insight into intervention-related changes to the bone-muscle unit.

Discussion

Results from the STRONG BONES trial have the potential to influence current clinical practice by determining the ability of bisphosphonate use to mitigate bone loss and concomitant fracture risk in middle-aged and older SG patients.

Risedronate use may blunt appendicular lean mass loss secondary to sleeve gastrectomy: Results from a pilot randomized controlled trial

Background

Despite robust weight loss and cardiometabolic benefit, lean mass loss following sleeve gastrectomy (SG) confers health risk. Bisphosphonates are a potential therapeutic agent for lean mass maintenance. Thus, our objective was to explore the effect of six months of risedronate (vs placebo) on change in dual energy x-ray absorptiometry (DXA) and computed tomography (CT) derived lean mass metrics in the year following SG.

Methods

24 SG patients were randomized to six months of 150 mg oral risedronate or placebo capsules (NCT03411902). Body composition was assessed at baseline and six months with optional 12-month follow-up using whole-body DXA and CT at the lumbar spine and mid-thigh. Group treatment effects and 95% CIs were generated from a mixed model using contrast statements at six and 12 months, adjusted for baseline values.

Results

Of 24 participants enrolled [55.7±6.7 years (mean±SD), 79% Caucasian, 83% women, body mass index (BMI) 44.7±6.3kg/m2], 21 returned for six-month testing, and 14 returned for 12-month testing. Six-month weight loss was -16.3 kg (-20.0, -12.5) and -20.9 kg (-23.7, -18.1) in the risedronate and placebo groups, respectively (p=.057). Primary analysis at six-months revealed a non-significant sparing of appendicular lean mass in the risedronate group compared to placebo [-1.2 kg (-2.3, -0.1) vs -2.1 kg (-3.0, -1.2)]; p=.20. By 12-months, the risedronate group displayed no change in appendicular lean mass from baseline [-0.5 kg (-1.5, 0.6)]; however, the placebo group experienced significantly augmented loss [-2.9 kg (-3.6, -2.1)].

Conclusion

Pilot data indicate risedronate treatment may mitigate appendicular lean mass loss following SG. Further study is warranted.

French recommendations on the prevention and treatment of osteoporosis secondary to bariatric surgery

INTRODUCTION

This article presents the initial recommendations of the Groupe de Recherche et d'Information sur les Ostéoporoses (Osteoporosis Research and Information Group [GRIO]) and the Société Française de Rhumatologie (French Rheumatology Society [SFR]) on the prevention and treatment of osteoporosis secondary to bariatric surgery.

METHODS

The recommendations were produced by a working group comprising 4 expert rheumatologists, 3 medically qualified nutritionists, 2 obesity surgeons, 1 physical activity specialist, and 1 patient-association representative.

RESULTS

The following generally recommended measures apply to all patients with an indication for bariatric surgery or who have already undergone bariatric surgery: normalize calcium and protein intake, attain a 25(OH) vitamin D concentration of between 30 and 60ng/mL; prevent the risk of falls, and introduce a suitable regimen of physical activity. An initial assessment of fracture risk should be routinely performed - ideally before the first bariatric surgery procedure - (i) in the case of RYGB and biliopancreatic diversion, regardless of age, (ii) in patients at high risk of fracture, regardless of age, and (iii) in all menopausal women and all men ≥ 50 years old, regardless of the type of bariatric surgical procedure. The fracture risk assessment is based on a determination of osteoporosis risk factors and bone mineral density measurements. Anti-osteoporosis treatment - zoledronic acid as the first line of treatment - is indicated for menopausal women and men ≥ 50 years old with (i) a history of severe fracture, regardless of T-score, (ii) a history of non-severe fracture and a T-score ≤ -1, and (iii) no history of fracture and a T-score ≤ -2.

CONCLUSIONS

There is an increased risk of fracture after bariatric surgery. Clinicians should focus their attention on patients at high fracture risk such as postmenopausal women and men older than 50 years. More research is necessary to direct and support guidelines.

Bone Response to Weight Loss Following Bariatric Surgery

Obesity is a global health challenge that warrants effective treatments to avoid its multiple comorbidities. Bariatric surgery, a cornerstone treatment to control bodyweight excess and relieve the health-related burdens of obesity, can promote accelerated bone loss and affect skeletal strength, particularly after malabsorptive and mixed surgical procedures, and probably after restrictive surgeries. The increase in bone resorption markers occurs early and persist for up to 12 months or longer after bariatric surgery, while bone formation markers increase but to a lesser extent, suggesting a potential uncoupling process between resorption and formation. The skeletal response to bariatric surgery, as investigated by dual-energy X-ray absorptiometry (DXA), has shown significant loss in bone mineral density (BMD) at the hip with less consistent results for the lumbar spine. Supporting DXA studies, analyses by high-resolution peripheral quantitative computed tomography (HR-pQCT) showed lower cortical density and thickness, higher cortical porosity, and lower trabecular density and number for up to 5 years after bariatric surgery. These alterations translate into an increased risk of fall injury, which contributes to increase the fracture risk in patients who have been subjected to bariatric surgery procedures. As bone deterioration continues for years following bariatric surgery, the fracture risk does not seem to be dependent on acute weight loss but, rather, is a chronic condition with an increasing impact over time. Among the post-bariatric surgery mechanisms that have been claimed to act globally on bone health, there is evidence that micro- and macro-nutrient malabsorptive factors, mechanical unloading and changes in molecules partaking in the crosstalk between adipose tissue, bone and muscle may play a determining role. Given these circumstances, it is conceivable that bone health should be adequately investigated in candidates to bariatric surgery through bone-specific work-up and dedicated postsurgical follow-up. Specific protocols of nutrients supplementation, motor activity, structured rehabilitative programs and, when needed, targeted therapeutic strategies should be deemed as an integral part of post-bariatric surgery clinical support.

Bariatric surgery and skeletal health: A narrative review and position statement for management by the European Calcified Tissue Society (ECTS)

CONTEXT

Numerous studies have demonstrated detrimental skeletal consequences following bariatric surgery.

METHODS

A working group of the European Calcified Tissue Society (ECTS) performed an updated review of existing literature on changes of bone turnover markers (BTMs), bone mineral density (BMD), and fracture risk following bariatric surgery and provided advice on management based on expert opinion.

LITERATURE REVIEW

Based on observational studies, bariatric surgery is associated with a 21-44% higher risk of all fractures. Fracture risk is time-dependent and increases approximately 3 years after bariatric surgery. The bariatric procedures that have a malabsorptive component (including Roux-en-Y Gastric bypass (RYGB) and biliopancreatic diversion (BPD)) have clearly been associated with the highest risk of fracture. The extent of high-turnover bone loss suggests a severe skeletal insult. This is associated with diminished bone strength and compromised microarchitecture. RYGB was the most performed bariatric procedure worldwide until very recently, when sleeve gastrectomy (SG) became more prominent. There is growing evidence that RYGB is associated with greater reduction in BMD, greater increase in BTMs, and higher risk of fractures compared with SG but RCTs on optimal management are still lacking.

EXPERT OPINION

In all patients, it is mandatory to treat vitamin D deficiency, to achieve adequate daily calcium and protein intake and to promote physical activity before and following bariatric surgery. In post-menopausal women and men older than 50 years, osteoporosis treatment would be reasonable in the presence of any of the following criteria: i) history of recent fragility fracture after 40 years of age, ii) BMD T-score ≤ -2 at hip or spine, iii) FRAX score with femoral neck BMD exceeding 20% for the 10-year major osteoporotic fracture probability or exceeding 3% for hip fracture. Zoledronate as first choice should be preferred due to intolerance of oral formulations and malabsorption. Zoledronate should be used with caution due to hypocemia risk. It is recommended to ensure adequate 25-OH vitamin D level and calcium supplementation before administering zoledronate.

CONCLUSIONS

The bariatric procedures that have a malabsorptive component have been associated with the highest turnover bone loss and risk of fracture. There is a knowledge gap on osteoporosis treatment in patients undergoing bariatric surgery. More research is necessary to direct and support guidelines.

Risedronate use to attenuate bone loss following sleeve gastrectomy: Results from a pilot randomized controlled trial

The purpose of this study was to explore the efficacy of 150 mg once monthly oral risedronate use in the prevention of sleeve gastrectomy (SG) associated bone loss. Twenty-four SG patients (56 ± 7 years, 83% female, 21% black) were randomized to risedronate or placebo for 6 months, with an optional 12-month assessment. Outcome measures included 6 (n = 21) and 12 (n = 14) month change in dual energy x-ray absorptiometry-acquired regional areal bone mineral density (aBMD). Six-month treatment effect estimates [mean (95% CI)] revealed significant between group aBMD differences at the femoral neck [risedronate: +0.013 g/cm² (-0.021, 0.046) vs. placebo: -0.041 g/cm² (-0.067, -0.015)] and lumbar spine [risedronate: +0.028 g/cm² (-0.006, 0.063) vs. placebo: -0.029 g/cm² (-0.054, -0.004)]; both p ≤ 0.02. When followed postoperatively to 12 months, differential aBMD treatment effects were observed at the total hip [risedronate: -0.035 g/cm² (-0.061, -0.009) vs. placebo: -0.072 g/cm² (-0.091, -0.052)] and lumbar spine [risedronate: +0.012 g/cm² (-0.038, 0.063) vs. placebo: -0.052 g/cm² (-0.087, -0.017)]; both p < 0.05. Preliminary treatment effect estimates signal 6 months of risedronate use may be efficacious in reducing aBMD loss at the axial skeleton post-SG, with benefit largely maintained throughout the 1-year postoperative period. Confirmatory data from an adequately powered trial are needed.