The Effect of Progestogen Add-back Therapy on Skeletal Status During GnRH Agonist Therapy for Endometriosis

Park, Hyoung Moo; Lee, Woo Seok; Song, Min Seok; Hur, Min

Abstract

OBJECTIVE
GnRH agonist used in the medical treatment of endometriosis, induces accelerated bone loss, which leads to osteoporosis. This study was performed to investigate the possibilities of prevention of bone loss by progestogen add-back therapy in GnRH agonist treatment.
METHODS
Thirty patients, who were diagnosed as endometriosis from Apr 1996 to Jun 2001, were divided into GnRH agonist treatment group and progestogen add-back therapy group. The changes of lumbar spine and femur BMD were checked from the onset of treatment to 6 months later, and the changes of bone markers (serum osteocalcin, urine deoxypyridinoline) from the onset of treatment, to 3 months later, to 6 months later, respectively.
RESULTS
In GnRH agonist group, the BMDs were decreased by 5.56%, 3.85%, 6.10% and 5.19% in lumbar spine, femur neck, ward triangle, and femur trochanter respectively. All of these changes were significant compared with basal BMDs at each sites. Basal serum osteocalcin level of 5.34+/-2.37 ng/ml was significantly and continuously increased to 8.87+/-3.06 ng/ml and 11.87+/-3.15 ng/ml at 3rd and 6th month of treatment respectively. Urinary deoxypyridinoline level was increased from basal 7.07+/-2.48 ng/ml to 9.56+/-3.13 ng/ml at 3rd month and 9.87+/-2.18 ng/ml respectively. The significant change was noted from 3rd month of treatment with no change between 3rd and 6th month of treatment. In MPA add-back therapy group, the BMDs after treatment were significantly decreased by 5.39% and 4.30% only in lumbar spine and ward triangle of femur compared with pretreatment basal BMD levels. But there was no significant change at femur neck and trochanter. Serum osteocalcin level was significantly increased from basal 8.02+/-3.25 ng/ml to 11.05+/-4.02 ng/ml at 6th month of treatment, while there was no change at 3rd month of treatment. Meanwhile urinary deoxypyridinoline level was not changed during treatment.
CONCLUSION
Although the decrease of BMD and the increase of bone turnover rate are induced during GnRH agonist therapy for endometriosis, progestogen add-back therapy could prevent these changes to some degree.