Efficacy of zoledronate, denosumab or teriparatide in postmenopausal women with type 2 diabetes mellitus at high risk of fragility fractures: protocol of an open, blinded endpoint randomized controlled pilot trial.

BACKGROUND

People with type 2 diabetes (T2D) are at high risk of fragility fractures; however, there are no randomized controlled trials evaluating the efficacy of anti-osteoporosis drugs as a primary pre-specified endpoint in T2D.

OBJECTIVES

To compare the efficacy of anti-osteoporotic drugs in postmenopausal women with T2D.

DESIGN

Prospective, randomized, open, blinded endpoint clinical pilot trial.

METHODS

Postmenopausal women (⩾50 years) with T2D (duration ⩾5 years), HbA1c 7-10%, eGFR ⩾45 mL/min/1.73 m and prior vertebral (clinical/morphometric), hip, radius, humeral fragility fracture bone mineral density (BMD) T-score (adjusted for diabetes) at lumbar spine/femoral neck ⩽-2.5 high FRAX score will be eligible for inclusion. Subjects with secondary causes of osteoporosis, prior exposure to bone-active therapies or history of use of glucocorticoids/pioglitazone/thiazides/canagliflozin will be excluded. Finally, eligible subjects will undergo estimation of serum calcium, phosphate, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D and bone turnover markers (BTMs) (total procollagen type I N-propeptide, β-CTX) along with trabecular bone score (TBS) and high-resolution peripheral quantitative computed tomography (HR-pQCT) of non-dominant hand and leg. After a 2-week run in phase, they will be randomized in a 1:1:1:1 ratio to receive yearly zoledronate, or biannually denosumab or daily teriparatide (in addition to standard of care, i.e., calcium 1000 mg/day and cholecalciferol 1000 IU/day) or only standard of care (control). The primary endpoints will be change in areal BMD and frequency of incident fractures at 18 months. The secondary endpoints will be change in HR-pQCT parameters, TBS and BTMs at 18 months. Adverse events will be recorded for all randomized participants.

ETHICS

The study has been approved by the Institute Ethics Committee. Written informed consent will be obtained from each participant.

DISCUSSION

The trial is expected to provide information regarding optimal anti-osteoporotic therapy in people with T2D and bone fragility.

REGISTRATION

Prospectively registered in Clinical Trial Registry of India (CTRI/2022/02/039978).