Gonadotropin-releasing hormone analogues for endometriosis

Endometriosis is a common gynaecological condition affecting 6 to 11% of reproductive-age women and may cause dyspareunia, dysmenorrhoea, and infertility. One treatment strategy is medical therapy with gonadotrophin-releasing hormone analogues (GnRHas) to reduce pain due to endometriosis. One of the adverse effects of GnRHas is a decreased bone mineral density. In addition to assessing the effect on pain, quality of life, most troublesome symptom and patients' satisfaction, the current review also evaluated the effect on bone mineral density and risk of adverse effects in women with endometriosis who use GnRHas versus other treatment options.

To assess the effectiveness and safety of GnRH analogues (GnRHas) in the treatment of painful symptoms associated with endometriosis and to determine the effects of GnRHas on bone mineral density of women with endometriosis.

We searched the Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO and the trial registries in May 2022 together with reference checking and contact with study authors and experts in the field to identify additional studies.

We included randomised controlled trials (RCTs) which compared GnRHas with other hormonal treatment options, including analgesics, danazol, intra-uterine progestogens, oral or injectable progestogens, gestrinone and also GnRHas compared with no treatment or placebo. Trials comparing GnRHas versus GnRHas in conjunction with add-back therapy (hormonal or non-hormonal) or calcium-regulation agents were also included in this review.  DATA COLLECTION AND ANALYSIS: We used standard methodology as recommended by Cochrane. Primary outcomes are relief of overall pain and the objective measurement of bone mineral density. Secondary outcomes include adverse effects, quality of life, improvement in the most troublesome symptoms and patient satisfaction.  Due to high risk of bias associated with some of the studies, primary analyses of all review outcomes were restricted to studies at low risk of selection bias. Sensitivity analysis including all studies was then performed.

Seventy-two studies involving 7355 patients were included. The evidence was very low to low quality: the main limitations of all studies were serious risk of bias due to poor reporting of study methods, and serious imprecision.  Trials comparing GnRHas versus no treatment  We did not identify any studies. Trials comparing GnRHas versus placebo There may be a decrease in overall pain, reported as pelvic pain scores (RR 2.14; 95% CI 1.41 to 3.24, 1 RCT, n = 87, low-certainty evidence), dysmenorrhoea scores (RR 2.25; 95% CI 1.59 to 3.16, 1 RCT, n = 85, low-certainty evidence), dyspareunia scores (RR 2.21; 95% CI 1.39 to 3.54, 1 RCT, n = 59, low-certainty evidence), and pelvic tenderness scores (RR 2.28; 95% CI 1.48 to 3.50, 1 RCT, n = 85, low-certainty evidence) after three months of treatment. We are uncertain of the effect for pelvic induration, based on the results found after three months of treatment (RR 1.07; 95% CI 0.64 to 1.79, 1 RCT, n = 81, low-certainty evidence). Besides, treatment with GnRHas may be associated with a greater incidence of hot flushes at three months of treatment (RR 3.08; 95% CI 1.89 to 5.01, 1 RCT, n = 100, low-certainty evidence). Trials comparing GnRHas versus danazol For overall pain, for women treated with either GnRHas or danazol, a subdivision was made between pelvic tenderness, partly resolved and completely resolved. We are uncertain about the effect on relief of overall pain, when a subdivision was made for overall pain (MD -0.30; 95% CI -1.66 to 1.06, 1 RCT, n = 41, very low-certainty evidence), pelvic pain (MD 0.20; 95% CI -0.26 to 0.66, 1 RCT, n = 41, very low-certainty evidence), dysmenorrhoea (MD 0.10; 95% CI -0.49 to 0.69, 1 RCT, n = 41, very low-certainty evidence), dyspareunia (MD -0.20; 95% CI -0.77 to 0.37, 1 RCT, n = 41, very low-certainty evidence), pelvic induration (MD -0.10; 95% CI -0.59 to 0.39, 1 RCT, n = 41, very low-certainty evidence), and pelvic tenderness (MD -0.20; 95% CI -0.78 to 0.38, 1 RCT, n = 41, very low-certainty evidence) after three months of treatment. For pelvic pain (MD 0.50; 95% CI 0.10 to 0.90, 1 RCT, n = 41, very low-certainty evidence) and pelvic induration (MD 0.70; 95% CI 0.21 to 1.19, 1 RCT, n = 41, very low-certainty evidence), the complaints may decrease slightly after treatment with GnRHas, compared to danazol, for six months of treatment. Trials comparing GnRHas versus analgesics  We did not identify any studies. Trials comparing GnRHas versus intra-uterine progestogens We did not identify any low risk of bias studies. Trials comparing GnRHas versus GnRHas in conjunction with calcium-regulating agents There may be a slight decrease in bone mineral density (BMD) after 12 months treatment with GnRHas, compared to GnRHas in conjunction with calcium-regulating agents for anterior-posterior spine (MD -7.00; 95% CI -7.53 to -6.47, 1 RCT, n = 41, very low-certainty evidence) and lateral spine (MD -12.40; 95% CI -13.31 to -11.49, 1 RCT, n = 41, very low-certainty evidence).  AUTHORS' CONCLUSIONS: For relief of overall pain, there may be a slight decrease in favour of treatment with GnRHas compared to placebo or oral or injectable progestogens. We are uncertain about the effect when comparing GnRHas with danazol, intra-uterine progestogens or gestrinone. For BMD, there may be a slight decrease when women are treated with GnRHas, compared to gestrinone. There was a bigger decrease of BMD in favour of GnRHas, compared to GnRHas in conjunction with calcium-regulating agents. However, there may be a slight increase in adverse effects when women are treated with GnRHas, compared to placebo or gestrinone. Due to a very low to low certainty of the evidence, a wide range of outcome measures and a wide range of outcome measurement instruments, the results should be interpreted with caution.