Treatment for patients with postmenopausal osteoporosis who have been placed on HRT and show a decrease in bone mineral density: effects of concomitant administration of vitamin K(2).

We have been using hormone replacement therapy (HRT) as the treatment of choice for menopausal symptoms and osteoporosis. Estrogen increases bone mineral density (BMD) for 2 or 3 years, and only maintains BMD thereafter. In the present study, we investigated whether BMD improved with HRT in combination with vitamin K(2). Ninety-four patients with postmenopausal osteoporosis were studied. All patients were placed on HRT for more than 1 year. Ten patients whose BMD had increased up to a plateau and showed a decreasing trend thereafter while they were receiving HRT were placed on HRT in combination with vitamin K(2). The long-term BMD (L(2)-L(4)) profiles of those receiving HRT alone, and the effects of HRT in combination with vitamin K(2) on the BMD profiles were examined. The rate of change in BMD (mean +/- SE) of all patients who underwent HRT alone was 2.9 +/- 1.2% 1 year after the initiation of HRT, 4.6 +/- 1.2% 2 years later, and 5.4 +/- 1.2% 3 years later. The BMD in these patients, which reached a peak increase after 3 years, no longer increased from the following year. When vitamin K(2) was administered concomitantly to 10 patients for 12 months because of the decrease in BMD, their BMD (mean +/- SE) increased significantly, from 0.734 +/- 0.021 g/cm(2) to 0.783 +/- 0.026 g/cm(2) ( P < 0.03; paired- t test). We conclude that HRT in combination with vitamin K(2) significantly improved BMD that was on the decrease after HRT alone. Therefore, as a supplementary drug for postmenopausal osteoporosis, vitamin K(2) is a good therapeutic option for patients who are placed on HRT.