Long-term use of gonadotropin-releasing hormone analogs and hormone replacement therapy in the management of endometriosis: a randomized trial with a 6-year follow-up.

OBJECTIVE: To identify the effects of long-term GnRH agonist use (6-24 months), with and without add-back therapy, and spontaneous reversibility of bone mass density (BMD) up to 6 years after treatment.

DESIGN: A prospective, randomized, long-term follow-up study.

SETTING: Obstetrics and gynecology department in a university hospital in the United Kingdom.

PATIENT(S): Forty-nine symptomatic women with a laparoscopic diagnosis of endometriosis who had been identified for treatment with long-acting GnRH agonist and volunteered to participate in the study.

INTERVENTION(S): Women were randomly allocated to receive hormone replacement therapy (HRT) as a daily oral dose of estradiol, 2 mg, and norethisterone acetate, 1 mg, or no treatment in addition to monthly subcutaneous implants of goserelin acetate for up to 2 years, until cessation of symptoms. Bone mineral density (BMD) at the lumbar spine (C2-C4) and hip (Ward triangle) was measured every 6 months.

MAIN OUTCOME MEASURE(S): BMD changes in both groups.

RESULT(S): 45 women were followed up for 6 years, at the end of which the groups did not differ significantly in the reduction in mean BMD at the lumbar spine or hip.

CONCLUSION(S): BMD reduction occurs during long-term GnRH agonist use and is not fully recovered by up to 6 years after treatment. Use of HRT does not affect this process.