Comparison of the effects of denosumab between a native vitamin D combination and an active vitamin D combination in patients with postmenopausal osteoporosis

The aim of this 12-month, retrospective study was to compare the effects of denosumab (DMAb; 60 mg subcutaneously every 6 months) plus native vitamin D (VD) (cholecalciferol) combination therapy with DMAb plus active VD analog (alfacalcidol) combination therapy in patients with postmenopausal osteoporosis. Patients [N = 127; mean age 75.6 years (range 58–93 years); 28 treatment-naïve patients, 59 patients treated with oral bisphosphonate therapy, 40 patients treated with teriparatide daily] were allocated to either (1) the DMAb plus native VD group (n = 60; cholecalciferol, 10 μg, plus calcium, 610 mg/day; 13 treatment-naïve patients, 28 patients treated with oral bisphosphonate therapy, and 19 patients treated with teriparatide daily) or (2) the DMAb plus active VD group [n = 67; alfacalcidol, 0.8 ± 0.0 μg, plus calcium, 99.2 ± 8.5 mg/day; 15 treatment-naïve patients, 31 patients treated with oral bisphosphonate therapy, and 21 patients treated with teriparatide daily) on the basis of each physician’s decision. Changes in bone mineral density (BMD), serum bone turnover marker levels, and fracture incidence were monitored every 6 months. There were no significant differences in baseline age, BMD, bone turnover marker levels, and prior treatments between the two groups. After 12 months, compared with the DMAb plus native VD group, the DMAb plus active VD group showed similar increases in the BMD of the lumbar spine (6.4% vs 6.5%) and total hip (3.3% vs 3.4%), but significantly greater increases in the BMD of the femoral neck (1.0% vs 4.9%, P < 0.001) and the distal part of the forearm (third of radius) (−0.8% vs 3.9%, P < 0.01). These tendencies were similar regardless of the differences in the prior treatments. The rates of decrease of bone turnover marker levels were similar for tartrate-resistant acid phosphatase isoform 5b (−49.0% vs −49.0%), procollagen type I N-terminal propeptide (−45.9% vs −49.3%), and undercarboxylated osteocalcin (−56.0  vs −66.5%), whereas serum intact parathyroid hormone levels were significantly lower in the DMAb plus active VD group (47.6 pg/mL vs 30.4 pg/mL, P < 0.001). The rate of hypocalcemia was 1.7% in the DMAb plus native VD group and 1.5% in the DMAb plus active VD group, and the rate of clinical fracture incidence was 8.3% in the DMAb plus native VD group and 4.5% in the DMAb plus active VD group, with no significant difference between the groups. DMAb with active VD combination therapy may be a more effective treatment option than DMAb with native VD combination therapy in terms of increasing BMD of the femoral neck and distal part of the forearm and also maintaining serum intact parathyroid hormone at lower levels.