Calcium and vitamin D supplementation with 3-year denosumab treatment is beneficial to enhance bone mineral density in postmenopausal patients with osteoporosis and rheumatoid arthritis

Abstract

Background: This 3-year retrospective study compared the outcomes of bisphosphonate-pretreated denosumab therapy with or without vitamin D and calcium supplementation in postmenopausal osteoporosis (OP) patients with rheumatoid arthritis (RA).

Materials and methods: Fifty-eight patients under long-term denosumab treatment were divided into groups without (denosumab group; 31 cases) or with (combination group; 27 cases) vitamin D and calcium supplementation. The bone markers of BAP, TRACP-5b, and urinary NTX were measured at baseline and every year for 3 years. We also evaluated bone mineral density (BMD) of the lumbar 1-4 vertebrae (L-BMD) and bilateral total hips (H-BMD) at the same time points.

Results: There were no significant differences in the percent changes of serum albumin-corrected calcium between the groups. The percent change in TRACP-5b was significantly higher in the combination group at 2 years. Serum 25-hydroxyvitamin D status was persistently high during therapy in both groups, with significant percent increases over baseline at 2 and 6 months in both groups and at 24 months in the combination group. The percent increase from baseline of serum zinc was significantly higher at 3 years in the combination group over the denosumab group. L-BMD and H-BMD were significantly increased at every time point for 3 years vs pretreatment levels in both groups and were significantly higher in the combination group at all time points.

Conclusion: Compared with denosumab monotherapy, the combination group displayed significantly increased serum zinc, L-BMD, and H-BMD at 3 years in OP patients with RA. Thus, calcium and vitamin D supplementation may be beneficial to enhance BMD gains, but not necessarily 25-hydroxyvitamin D status, in patients with OP and RA under denosumab.

Keywords: 25(OH)D; bone mineral density; bone-related minerals; denosumab; osteoporosis; rheumatoid arthritis.

Figure 1

Percent changes of serum albumin-corrected calcium (Ca) (A), serum phosphorus (B), whole parathyroid hormone (PTH) (C), and serum 1,25(OH)₂D₃ (D) at 12, 24, and 36 months (M). Circles show the denosumab group and triangles show the combination group.

Figure 2

Percent changes of serum zinc (A), serum iron (B), and serum magnesium (C) at 12, 24, and 36 months (M). Notes: Circles show the denosumab group and triangles show the combination group. Single and double asterisks indicate a significant difference (P<0.01 and P<0.05, respectively) with baseline values.

Figure 3

Percent changes of serum tartrate-resistant acid phosphatase (TRACP)-5b (A), urinary cross-linked N-terminal telopeptide of type I collagen (NTX) (B), serum bone alkaline phosphatase (BAP) (C), and serum 25-hydroxyvitamin D (25(OH)D) (D) at 12, 24, and 36 months (M). Circles show the denosumab group and triangles show the combination group. Notes: Double hashtags indicate a significant difference (P<0.01) between the denosumab and combination groups. Single and double asterisks indicate a significant difference (P<0.05 and P<0.01, respectively) with baseline values.

Figure 4

Percent changes in lumbar bone mineral density (L-BMD) (A) and bilateral total hip BMD (H-BMD) (B) at 12, 24, and 36 months (M). Notes: Single and double hashtags indicate a significant difference (P<0.05 and P<0.01, respectively) between the denosumab and combination groups. Double asterisks indicate a significant difference (P<0.01) with baseline values.