Use of mixed-treatment-comparison methods in estimating efficacy of treatments for heavy menstrual bleeding

BACKGROUND: A variety of pharmacological and surgical treatments have been developed for heavy menstrual bleeding (HMB), which can have negative physical, social, psychological, and economic consequences. We conducted a systematic literature review and mixed-treatment-comparison (MTC) meta-analysis of available data from randomized controlled trials (RCTs) to derive estimates of efficacy for 8 classes of treatments for HMB, to inform health-economic analysis and future studies. METHODS: A systematic review identified RCTs that reported data on menstrual blood loss (MBL) at baseline and one or more follow-up times. Eight treatment classes were considered: COCs, danazol, endometrial ablation, LNG-IUS, placebo, progestogens given for less than 2 weeks out of 4 during the menstrual cycle, progestogens given for close to 3 weeks out of 4, and TXA. The primary measure of efficacy was the proportion of women who achieved MBL < 80 mL per cycle (month), as measured by the alkaline hematin method. A score less than 100 on an established pictorial blood-loss assessment chart (PBAC) was considered an acceptable substitute for MBL < 80 mL. Estimates of efficacy by treatment class and time were obtained from a Bayesian MTC model. The model also included effects for treatment class, study, and the combination of treatment class and study and an adjustment for baseline mean MBL. Several methodological challenges complicated the analysis. Some trials reported various summary statistics for MBL or PBAC, requiring estimation (with less precision) of % MBL < 80 mL or % PBAC < 100. Also, reported follow-up times varied substantially. RESULTS: The evidence network involved 34 RCTs, with follow-up times from 1 to 36 months. Efficacy at 3 months of follow-up (estimated as the posterior median) ranged from 87.5% for the levonorgestrel-releasing intrauterine system (LNG-IUS) to 14.2% for progestogens administered for less than 2 weeks out of 4 in the menstrual cycle. The 95% credible intervals for most estimates were quite wide, mainly because of the limited evidence for many combinations of treatment class and follow-up time and the uncertainty from estimating % MBL < 80 mL or % PBAC < 100 from summary statistics. CONCLUSIONS: LNG-IUS and endometrial ablation are very efficacious in treating HMB. The study yielded useful insights on using MTC in sparse evidence networks. Diversity of outcome measures and follow-up times in the HMB literature presented considerable challenges. The Bayesian credible intervals reflected the various sources of uncertainty.