Increased reduction in bone density and skin thickness in postmenopausal women taking long-term corticosteroid therapy: a suggested role for estrogen add-back therapy.

BACKGROUND

Long-term corticosteroid therapy is complicated by osteoporosis and generalized thinning of the skin. These two complications of such therapy were routinely assessed at the Menopause Clinic of St. Luke's Hospital Medical School, University of Malta.

METHODS

A cross-sectional study was performed on 64 postmenopausal women who had been taking long-term corticosteroids. Each woman had her skin thickness measured using high-resolution ultrasound (22 MHz) and her bone density measured by dual-energy X-ray absorptiometry (DEXA). These measurements were compared with those of a control group (n = 557), a group of women who had sustained osteoporotic fractures (n = 180) and a group of women taking hormone replacement therapy (HRT) (n = 399). A longitudinal study of 29 postmenopausal women taking corticosteroids was also performed. This study compared results for women who, in addition to their corticosteroids, were taking HRT and for those who were taking corticosteroids alone.

RESULTS

The cross-sectional study showed that corticosteroid therapy was associated with the lowest mean skin thickness measurement (0.83 mm). Similarly, low mean bone density measurements for the lumbar spine (0.805 g/cm2) and left hip (0.715 g/cm2) were obtained for this group. The mean skin thicknesses in the control group and the HRT group were 0.93 mm and 0.935 mm, respectively, while that in the osteoporotic fracture group was 0.88 mm. The bone density of the fracture group was similar to that of the group of women taking long-term corticosteroids, with the lumbar spine having a mean density of 0.805 g/cm2 and 0.81 g/cm2, and the left hip having a density of 0.705 g/cm2 and 0.715 g/cm2, respectively. Bone densities were similar for the control group and the HRT group, and higher than that of the corticosteroid or fracture group. The lumbar spine had a mean density of 0.925 g/cm2 in the control group and 0.93 g/cm2 in the hormonally treated group. Both the treated and control groups had similar bone densities of the left hip at about 0.82 g/cm2. The small longitudinal study compared postmenopausal women on long-term corticosteroid therapy taking HRT with another group who were not taking HRT. This 4-year study revealed mean total increases in skin thickness of 6.1% and bone density of 5.5% (left hip) and 14.6% (lumbar spine) in the HRT group, since the start of the study. Conversely, the control group registered reductions over 4 years in both skin thickness (2.8%) and bone density (lumbar spine 4.5% and hip 5.0%).

CONCLUSION

In postmenopausal women taking long-term corticosteroids, skin thickness and bone density were both decreased, but the addition of HRT as add-back improved the situation dramatically. Skin thickness and bone density in women taking long-term corticosteroids were comparable to those in women who had sustained osteoporotic fractures. It is therefore suggested that HRT be used as add-back therapy in postmenopausal women taking long-term corticosteroid therapy.