Zoledronic Acid for Prevention of Bone Loss After BAriatric Surgery (ZABAS) (ZABAS)

  • End date
    Jun 1, 2024
  • participants needed
  • sponsor
    Stinus Gadegaard Hansen
Updated on 1 July 2022
zoledronic acid


In a randomised placebo-controlled trial assess effects of zoledronic acid for prevention of bone and muscle loss after bariatric surgery.


In individuals with severe obesity, bariatric surgery effectively reduces body weight, improves obesity related diseases and lowers mortality. A loss of bone and muscle mass and an increase in bone fracture risk are however seen after surgery. In this study it is examined if treatment with zoledronic acid (a drug used to treat osteoporosis) can prevent the bone and muscle loss after bariatric surgery. A single infusion of zoledronic acid or placebo is given before surgery. The study is blinded and randomized for methodological reasons. Bone and muscle scans, tests of muscle strength and physical performance and blood samples (for analysis of markers related to bone and muscle metabolism) are performed at inclusion and 12 and 24 months after surgery. A total of 60 adult individuals will participate. Results will be important for the evidence-based care of patients undergoing bariatric surgery and zoledronic acid.

Study design This is a single center randomized double-blind placebo-controlled study of zoledronic acid for prevention of bone and muscle loss after bariatric surgery. Routine bariatric surgery (RYGB or gastric sleeve) will be performed. The end of study is 24 months after surgery.

Study Population Patients referred for bariatric surgery at The Hospital South West Jutland, Esbjerg will be invited to participate.

Randomization After inclusion and baseline assessment, patients will be randomly assigned to either zoledronic acid or placebo with a 1:1 allocation. A randomization code stratifying an equal number of participants having RYGB or SG into each study arm will be applied.

Condition Bone Loss, Muscle Atrophy, Bariatric Surgery
Treatment Placebo, Zoledronic Acid
Clinical Study IdentifierNCT04742010
SponsorStinus Gadegaard Hansen
Last Modified on1 July 2022


Yes No Not Sure

Inclusion Criteria

years old or older
Eligible for bariatric surgery (BMI>35 kg/m2 with obesity-related comorbidity)

Exclusion Criteria

Pregnancy or breastfeeding
Chronic kidney disease with estimated GFR<45 ml/min
Hypersensitivity to bisphosphonates, mannitol, sodium citrate or water
Metabolic bone disease (osteoporosis is allowed)
Prior treatment with anti-osteoporotic agents
Treatment with oral glucocorticoids
Other diseases with known effects on bone metabolism
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