原発性骨粗鬆症患者における長期ビスホスホネート治療一時休止後のエルデカルシトール投与の効果

Efficacy of Eldecalcitol after Temporary Discontinuation of Long-term Bisphosphonate Therapy in Patients with Primary Osteoporosis

　背景：歯科治療を要するビスホスホネート(BP)内服患者が，中止か継続かで困惑し代替薬が望まれている．本研究はBPからエルデカルシトール(ELD)切り替え時の影響を検討した．

　対象・方法：対象は3年以上BPを内服した17例である．切り替え6カ後の骨密度：腰椎と大腿骨total(H-BMD)，骨代謝マーカー：TRACP-5b，P1NP，TRACP-5b/P1NPの変化を検討した．

　結果：有意な変化は，TRAP-5b/P1NPの低下のみだった．骨密度は維持され，骨代謝回転は骨形成が上昇した．しかし，H-BMD YAM＜70%の症例では，骨密度が大きく減少していた．

　まとめ：H-BMD YAM70%未満を除外すれば，ELDは，短期のBP代替薬となる可能性がある．

　Background：Since there are no clear criteria for discontinuing bisphosphonate (BP) therapy before dental treatment, switching to an alternative drug is desirable.

　Methods：The subjects were 17 primary osteoporosis patients who had been treated with a BP for ≥3 years.　Changes in bone mineral density (BMD) and in the levels of the bone metabolic markers TRACP-5b, P1NP, and TRACP-5b/P1NP were assessed 6 months after replacing BP with eldecalcitol (ELD).

　Results：The only significant change was a decrease in the TRACP-5b/P1NP level.　When 70% of the young adult mean (%YAM) bone mineral density at the time of the drug replacement was used as the cutoff value, the patients whose %YAM of the hip was ＜70% had lower hip BMD at the end of the 6 months.

　Conclusion：BMD was maintained and the bone formation component of bone turnover was higher 6 months after replacing BP with ELD.　ELD appears to be an effective short-term alternative to BP as a means of allowing dental treatment to proceed in patients whose %YAM of hip BMD is ≤70% at the time of drug replacement.