Bone Abstracts

Introduction: We aimed to study efficacy of zoledronic acid (Zol) in the treatment of postmenopausal osteoporosis within 3 years.

Methods: Clinical, bone mineral density (BMD) by DEXA (L1–L4, femoral Neck) (baseline, 12, 24, and 36 months); biochemical; immunoenzyme assay of bone turnover markers (BTM) – osteocalcin (OK) β-C-terminal telopeptides of type 1 collagen (CTX) (baseline, 1, 3, 6, 9, and 12 after one, two, three infusions).

Results: 225 women with postmenopausal osteoporosis (using T-score DEXA) were treated with Zol 5 mg as a once-yearly infusion for 3 years+2500 mg of calcium carbonate+800 ME vitamin D₃ daily. 107 (47.5%) patients had previous atraumatic fractures. After the 1st infusion of Zol we observed a significant decrease in CTX – 88% (P=0.008), −84,−82, −75, and −63%; in OK −28% (P=0.026), −49, −51, −46, and −42%. After the 2nd and 3rd infusions of Zol the reaction of BTM was similar, though in a lesser degree after each subsequent infusion. At the L1–L4 BMD increased by 7%, at the femoral neck by 5.9% after 36 months (P<0.05).

Conclusions: Zol has a powerful antiresorptive effect on bone turnover. Preferential suppression of bone resorption led to a positive balance of bone turnover and increase in BMD in the lumbar spine and the femoral neck. Measurement of CTX after 1 month of infusion provides for evaluation of a patient’s response to therapy with Zol and reveal ‘poor’ responders.