Clinical efficacy of add-back therapy in treatment of endometriosis: a meta-analysis

A meta-analysis was conducted to determine the effectiveness of using gonadotropin-releasing hormone analogues (GnRH-a), both with and without hormonal add-back therapy, for the management of endometriosis. Cochrane library, Ovid (Embase) and Pubmed databases were searched between the years 1998 and 2013 for published, prospective, randomised controlled trials (RCT) that assessed the effectiveness of add-back therapy for EMs treatment. The meta-analysis was performed using RevMan V5.0. The main outcome measures were as follows: lumbar spine bone mineral density (BMD) immediately after treatment and after 6 months of follow-up; femoral neck BMD; serum estradiol levels; changes in the Kupperman index score; the pelvic pain score, including dysmenorrhoea and dyspareunia; and pelvic tenderness. A total of 13 RCT, including 945 participants, were identified. The evidence suggested that add-back therapy was more effective for symptom relief than GnRH-a alone. BMD was significantly different when comparing add-back therapy to GnRH-a alone, both immediately after treatment and at 6 months. The add-back therapy increased serum oestrogen and did not reduce the efficacy of GnRH-a for treating dysmenorrhoea and dyspareunia. A variety of add-back regimens had a same effect for the treatment of endometriosis. Add-back therapy, based on the GnRH-a dose, does not reduce the efficacy of using GNRH-a for the management of endometriosis. Add-back therapy reduced the occurrence of side effects that can occur with GnRH-a therapy alone, such as osteoporosis and menopausal syndrome. There were no statistically significant differences when comparing the effectiveness of a variety of add-back regimens to each other.