Correction of vitamin D insufficiency with combined strontium ranelate and vitamin D3 in osteoporotic patients.

OBJECTIVE

This study aims to investigate the efficacy and safety of oral fixed-dose combination of strontium ranelate 2  g/vitamin D₃ 1000  IU daily vs strontium ranelate 2  g daily for correcting vitamin D insufficiency in osteoporosis.

DESIGN

A 6-month international, randomized, double-blind, parallel-group, phase 3 study.

METHODS

A total of 518 men and postmenopausal women aged ≥50 years with primary osteoporosis (T-score ≤-2.5 s.d.) and serum 25-hydroxyvitamin D (25(OH)D) >22.5 nmol/l were included. Patients were allocated to strontium ranelate 2 g/vitamin D₃ 1000  IU daily (n=413) or strontium ranelate 2 g daily (n=105). The participants received calcium 1 g daily. The primary endpoint was serum 25(OH)D at last post-baseline evaluation during 3 months.

RESULTS

Both groups were comparable at baseline. Mean baseline of 25(OH)D was 44.1 ± 14.6 nmol/l. After 3 months, the percentage of patients with 25(OH)D ≥50 nmol/l was higher with strontium ranelate/vitamin D₃ vs strontium ranelate (84 vs 44%, P<0.001; adjusted between-group odds ratio=6.7; 95% CI, 4.2-10.9). The efficacy of the fixed-dose combination on 25(OH)D was maintained at 6 months (86 vs 40%, P<0.001). Mean 25(OH)D was 65.1 and 49.5 nmol/l, respectively, after 3 months and 66.9 and 45.4 nmol/l after 6 months. Physical performance improved in both groups. Falls were 17 and 20% in the strontium ranelate/vitamin D₃ and strontium ranelate groups respectively. Parathyroid hormone levels were inversely correlated with 25(OH)D. No clinically relevant differences in safety were observed.

CONCLUSIONS

This study confirms the efficacy and safety of fixed-dose combination of strontium ranelate 2 g/vitamin D₃ 1000 IU for correction of vitamin D insufficiency in osteoporotic patients.