Comparison of the effectiveness of levonorgestrel intrauterine system and dienogest in the management of adenomyosis: A systematic review and meta-analysis

Background: Adenomyosis is a gynaecological lesion that impairs female fertility and contributes to reduced quality of life. There are several surgical and medical options for the management of this lesion; however, women who wish to conceive opt for medical therapies such as the levonorgestrel intrauterine device (LNG-IUS) and dienogest, which have various outcomes. To date, there is no consensus regarding which is more effective. Objectives: To compare the effectiveness of LNG-IUS and dienogest for the management of adenomyosis, and explore the risk of occurrence of known side effects for both treatments. Design: Systematic review and meta-analysis exploring the effectiveness of LNG-IUS and dienogest for the management of adenomyosis. Methods: A literature search was conducted using PICO guidelines and EMBASE, PubMed/MEDLINE, Scopus and Web of Science databases. Only clinical trials were collected and analysed. Results: Of the 792 studies that were initially identified, six were eligible for inclusion in this study. The studies included a total of 707 women; of these, 270 were treated with LNG-IUS, 354 were treated with dienogest, and 83 were controls. All the studies were from Asia (Bangladesh n = 1, China n = 2, Indian = 1, Japan n = 1, South Korean = 1). Dienogest was found to reduce pelvic pain significantly, evidenced by a lower visual analogue scale score, compared with LNG-IUS. Also, dienogest led to a significant reduction in uterine volume compared with LNG-IUS. However, subjects in the LNG-IUS group had significantly higher levels of haemoglobin than those in the dienogest group. Nonetheless, the occurrence of side effects such as weight gain, breast tenderness/distension, headache, insomnia/sleep disorder, depression/mood disorder, skin disorder/acne, and coital discomfort/ reduced libido were comparable in both treatment groups. Conclusion: Dienogest may be more effective than LNG-IUS for the management of adenomyosis, as it shows a superior effect in the reduction of pelvic pain and uterine volume. As only six studies were included in the present meta-analysis due to the paucity of data in the literature, it is recommended that well-designed randomized controlled trials comparing the effectiveness of dienogest with LNG-IUS should be conducted.