Purpose: To compare the response to denosumab (DMAb) therapy with that of oral bisphosphonate (BISPH) treatment in postmenopausal women with primary osteoporosis (PO).
Methods: In this retrospective study, we compared data of 75 PO female patients treated for 24 months with DMab (DMAb Group, age 72.6 ± 8.9 years) with those of 75 PO patients treated with oral bisphosphonates (BISPH Group), matched for age, body mass index, femoral bone mineral density (BMD), prevalent fragility fractures and familiar history of hip fracture. In all subjects at baseline and after 24 months we assessed the calcium-phosphorous metabolism parameters, BMD at lumbar spine (LS-BMD) and femoral neck (FN-BMD) by dual X-ray absorptiometry and the morphometric vertebral fractures by radiograph. The patients were considered inadequate responders in the presence of ≥ 2 incident fragility fractures and/or a decrease in BMD greater than the least significant change (LS 2.8%, FN 5.9%).
Results: After 24 months, the DMab Group showed a greater ALP decrease (- 22.8 ± 18.2%), a higher LS-BMD and FN-BMD increase (6.6 ± 6.9 and 4.4 ± 8.2%, respectively) and a lower number of patients with an incident fracture (8%) and with an inadequate response (6.7%) than BISPH Group (- 14.9 ± 15.3, 2.5 ± 4.3, 1.9 ± 4.5, 21.3 and 22.7%, respectively, p < 0.05 for all comparisons). The inadequate response was 4.5-fold more likely in BISPH Group than in DMab one (p = 0.027), regardless of possible confounders.
Conclusions: In postmenopausal PO females, denosumab was more effective than oral bisphosphonates in increasing BMD and reducing bone turnover and the number of inadequate responder patients.
Keywords: Bone mineral density; Denosumab; Fragility fractures; Oral bisphosphonates.