17p-estradiol (1 mg daily) in continuous combination with dydrogesterone (5.10 or 20 mg daily) increases bone mineral density in postmenopausal women

Although the minimal dose of 17/3-estradiol in hormone replacement regimens was originally considered to be 2 mg a day, it is now increasingly accepted that a lower dose of 1 mg a day is effective in protecting women from the detrimental effects of the menopause. A 1-year, multicentre, double-blind, randomized study was conducted in 214 healthy postmenopausal women in order to assess the effect of 17(3-estradiol (1 mg a day) continuously combined with dydrogesterone (5,10 or 20 mg/day) in preventing bone loss. Bone mineral density (BMD) was evaluable in 177 women who completed the study. In all women, a statistically significant increase from baseline in lumbar vertebrae (L.2~L4) BMD was seen after 6 months (+ 2,4%; p<0,01); this increase was somewhat greater after 12 months (+ 3,6%;p < 0,01). Similar effects were seen in the hip. After 6 months, BMD in the femoral neck, Ward’s triangle and trochanter had increased by 0,20% (not significant [n.s.]), 0,32% (n.s.)and 1,08% (p<0,01), respectively, compared with baseline. Greater increases were again seen after 12 months (+1,16%, + 1,62% and +2,83%, respectively), all of which were statistically significant (p<0,01) compared with baseline. The change in BMD from baseline did not diff er significantly between the three dydrogesterone dosages for either L.2~L4 or hip. All dosages were well tolerated and amenorrhoea was achieved in over 70%. In conclusion, 17(3-estradiol (1 mg/day) continuously combined with dydrogesterone (5, 10 or 20 mg/day) results in a significant increase in lumbar vertebrae and hip BMD in postmenopausal women. The lower dose of oestrogen and the avoidance of cyclical bleeding make this a particularly suitable regimen for the prevention and treatment of osteoporosis in older women.