Comparison Between Levonorgestrel-Releasing Intrauterine Device and Dienogest for Adenomyosis: A Systematic Review with Meta-Analysis

OBJECTIVE: To assess the pre-treatment severity of adenomyosis and compare the effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) with that of dienogest (DNG) over various follow-up periods. DATA SOURCES: We used a comprehensive Population, Intervention, Comparison, and Outcomes (PICO) search strategy, including PubMed and Embase. The inclusion criteria were limited to randomized controlled trials or retrospective clinical trials, focusing on primary outcomes such as dysmenorrhea, uterine volume (UV), and menstrual blood loss. DATA EXTRACTION AND SYNTHESIS: An initial screening of 235 publications yielded 8 studies that met the inclusion criteria, involving a total of 527 patients-277 receiving LNG-IUS and 250 undergoing DNG treatment. Baseline assessments showed severe dysmenorrhea (Visual Analog Scale [VAS] score: 6.826), increased UV (152.603 cm3), and significant menstrual blood loss (Pictorial Blood Loss Assessment Chart [PBAC] score: 108.705). Patients were divided into 3 groups following assessments after 3, 6, and 12 months. At the 3-month and 6-month follow-up, no significant differences were observed in dysmenorrhea, UV, or menstrual blood loss between the LNG-IUS and DNG groups. At the 12-month follow-up, 1 study reported that the LNG-IUS was associated with a significant reduction in UV, whereas DNG therapy led to a decrease in the severity of dysmenorrhea. CONCLUSION: Both LNG-IUS and DNG are both useful for managing adenomyosis, though they exhibit different therapeutic effects. LNG-IUS helps in decreasing UV, whereas DNG more notably alleviates dysmenorrhea. Despite these findings, only 8 studies were included in this meta-analysis, calling for further large-scale, randomized controlled trials to compare these interventions' efficacy and to develop robust, evidence-based treatment protocols.