[Effects on bone mass of oral alendronate, hormone replacement therapy and combined regimes in post-menopausal women: preliminary report on a comparative study].

The results of a prospective study that compared the short term effects on skeletal bone of oral alendronate, transdermal hormone replacement therapy (HRT) and two combined regimens with both medications are reported. Ninety six posmenopausal women with osteopenia (WHO classification) in lumbar spine or femoral neck measured by DEXA (table 1) were included in 4 therapeutic groups: Group I (n:19): 17 beta-Estradiol 50 micrograms daily transdermally/medroxiprogesterone 2.5 mg orally per day; Group II (n:42): alendronate 10 mg/day orally; Group III (n:15): HRT + alendronate 10 mg/day and Group IV (n:20): HTR + alendronate 5 mg/day. After 12 month treatment, lumbar bone mineral density (BMD) significantly increased to 3.6%; 4.1%; 6.5% y 3.1% in group I to IV, respectively (p < 0.01; figure 1). Differences among groups do not reached statistical significance. The percentage of responders to medication in each group was of 68.8%; 92%; 90% y 83%, respectively. Bone mineral density in femoral neck (FN) increased with all regimens, though mean values did not surpass method variation coefficient. Differences from baseline were statistically significant in group I (p < 0.05). The percentage of responders in this region was 58.8%; 60%; 62.5% y 45.5%, respectively. Biochemical bone markers (table 2), especially urinary pyridinoline and serum osteocalcin, showed a trend in bone metabolism inhibition that was more sustained in group III, as show mainly by the bone markers pyridinolines and osteocalcin. It is concluded that either single therapy with alendronate or estrogen or their combination halted bone loss in most patients leading to bone mass gain mainly in lumbar spine in the short term. However, bone effects with hormone replacement therapy in association with alendronate 10 mg were comparatively major, indicating the potential benefits of this regimen in the long term.