Zoledronic Acid for prevention of bone and muscle loss after BAriatric Surgery (ZABAS)-a study protocol for a randomized controlled trial

Abstract

Background Bariatric surgery has adverse effects on the muscular-skeletal system with loss of bone mass and muscle mass and an increase in the risk of fracture. Zoledronic acid is widely used in osteoporosis and prevents bone loss and fracture. Bisphosphonates may also have positive effects on skeletal muscle. The aim of this study is to investigate the effects of zoledronic acid for the prevention of bone and muscle loss after bariatric surgery. Methods/design This is a randomized double-blind placebo-controlled study. Sixty women and men with obesity aged 35 years or older will complete baseline assessments before randomization to either zoledronic acid (5 mg in 100 ml isotonic saline) or placebo (100 ml isotonic saline only) 3 weeks before surgery with Roux-en-Y-gastric bypass (RYGB) or sleeve gastrectomy (SG). Follow-up assessments are performed 12 and 24 months after surgery. The primary outcome is changes in lumbar spine volumetric bone mineral density (vBMD) assessed by quantitative computed tomography (QCT). Secondary bone outcomes are changes in proximal femur vBMD assessed by QCT. Changes in cortical and trabecular bone microarchitecture and estimated bone strength will be assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT). Cortical material bone strength at the mid-tibia diaphysis will be assessed using microindentation and fasting blood samples will be obtained to assess biochemical markers of bone turnover and calcium metabolism. Secondary muscle outcomes include whole body lean mass assessed using dual-energy X-ray absorptiometry. Dynamometers will be used to assess handgrip, shoulder, ankle, and knee muscle strength. Short Physical Performance Battery, 7.6-m walking tests, 2-min walking test, and a stair climb test will be assessed as biomarkers of physical function. Self-reported physical activity level is assessed using International Physical Activity Questionnaire (IPAQ). Discussion Results from this study will be instrumental for the evidence-based care of patients undergoing bariatric surgery. Trial registration ClinicalTrials.gov NCT04742010. Registered on 5 February 2021.

Intersession reliability of lower limb muscle strength assessments in adults with obesity eligible for bariatric surgery

“…Body weight was measured using a Seca scale (Gmbh & Co.; model 8997021094) while body composition [body fat%, fat mass (kg) and skeletal muscle mass (kg)] was assessed using bioelectrical impedance analysis (InBody 770 Co.). Before the muscle strength assessment, the participants performed a general warm-up for the lower extremities consisting of two 3 m (Gam et al, 2022) and 10 m walk tests (Wolf et al, 1999) performed at habitual walking speed, the 7.6 m (Gam et al, 2022) and 10 m walk test (Wolf et al, 1999) performed as fast as possible and the Stair Climb Power Test (ascending nine steps as fast as possible) (Gam et al, 2022). Finally, five repetitions (Gam et al, 2022) and 30 s sit-to-stand tests (Alcazar et al, 2020) were performed once each.…”

“…Before the muscle strength assessment, the participants performed a general warm‐up for the lower extremities consisting of two 3 m (Gam et al, 2022) and 10 m walk tests (Wolf et al, 1999) performed at habitual walking speed, the 7.6 m (Gam et al, 2022) and 10 m walk test (Wolf et al, 1999) performed as fast as possible and the Stair Climb Power Test (ascending nine steps as fast as possible) (Gam et al, 2022). Finally, five repetitions (Gam et al, 2022) and 30 s sit‐to‐stand tests (Alcazar et al, 2020) were performed once each. The data from these physical performance tests were utilized as a secondary outcome in another unpublished research project.…”

“…The maximum allowed body weight for the Biodex‐system is 195 kg. Brief description of the test protocol has been published elsewhere (Gam et al, 2022). In detail, participants were seated upright with their hip flexed at 85° in the dynamometer chair.…”