Effects of a 'Drug Holiday' on Bone Mineral Density and Bone Turnover Marker During Bisphosphonate Therapy

ABSTRACT

BACKGROUND: Recently long-term safety of bisphosphonate raises issues about the duration of therapy. We examined the effects of a drug holiday (DH) on bone mineral density (BMD) and bone turnover markers. METHODS: In Korean, 125 women of 50 years of age or older with T-score or =5 years started DH in 2006. Lumbar (L1-4), left femoral neck, total BMD, serum parameter (beta-crossLaps [CTx], phosphorus, total calcium, total alkaline phosphatase), and urinary parameter (calcium/creatinine ratio) were measured before, the time of starting, and after DH. RESULTS: After DH, lumbar, femoral neck and total BMD did not change significantly (0.757+/-0.093-->0.747+/-0.102, P=0.135, 0.567+/-0.079-->0.560+/-0.082, P=0.351, 0.698+/-0.008-->0.691+/-0.090 g/cm2, P=0.115, respectively). Serum CTx and total alkaline phosphatase were increased significantly (0.205+/-0.120-->0.791+/-0.44 ng/mL, P60.42+/-15.543 IU/L, P=0.001, respectively). Urinary calcium/creatinine ratio increased significantly (0.132+/-0.076-->0.156+/-0.093, P=0.012). CONCLUSIONS: A DH could be cautiously considered in patients with long-term use of bisphosphonate if there is a concern about severe suppression of bone turnover with respect to long-term use because insignificant changes of BMD and significant increase of bone turnover markers are shown during the period.