Objective To evaluate the efficacy and safety of mifepristone for perimenopause dysfunctional uterine bleeding (PDUB). Methods Such databases as VIP, CNKI, Wanfang and CBM were retrieved for collecting randomized controlled trials (RCTs) on mifepristone for PDUB. The quality of included studies was evaluated and Meta-analysis was performed according to the Cochrane methods. Results Forty RCTs involving 3 850 PDUB patients were included. The control group was divided into two sub-groups according to the features of intervention drugs: the sub-group of diagnostic curettage plus progestational hormone, and the sub-group of diagnostic curettage plus antiestrogenic drugs. The Meta-analysis indicated that compared with the sub-group of diagnostic curettage plus progestational hormone, the diagnostic curettage plus mifepristone group was more effective to increase the total effective rate, such as improving symptoms and signs of PDUB (RR=1.11, 95%CI 1.06 to 1.16, Plt;0.000 01), and to reduce recurrence (RR=0.44, 95%CI 0.36 to 0.52, Plt;0.000 01). But no differences were found between the two groups in the change of endometrial thickness, contents of hemoglobin, and serum level of FSH, LH, E2 and P hormone. Both the intervention and control groups appeared mild adverse reactions, such as rashes, tidal fever, nausea, anorexia, vomiting and breast distending, but with no liver and kidney damages. The long-term safety failed to be evaluated due to short follow-up time. Conclusion Based on this review, diagnostic curettage plus mifepristone shows certain advantage in the treatment of PDUB including the total effective rate and reducing recurrence. But there is no difference in regulating sex hormone level, inhibiting endometrial proliferation and improving anemia compared with the group of diagnostic curettage plus progestational hormone. However, this evidence is not b enough due to the low quality of included trials, possible bias risk, and failure of evaluating its long-term safety.
Sample size re-estimation (SSR) refers to the recalculation of the sample size using the existing trial data as original planned to ensure that the final statistical test achieved the pre-defined goals. SSR can enhance research efficiency, save trial costs, and accelerate the research process. Depending on whether the group assignment of the patients is known, SSR is divided into blinded sample size re-estimation and unblinded sample size re-estimation. Blinded sample size re-estimation can estimate the variance of the primary evaluation index through the EM algorithm or single sample variance re-estimation method, and then calculate the sample size. Unblinded sample size re-estimation can calculate the sample size by estimating the overall variance or therapeutic effect difference, but it needs to control the family wise type I error (FWER) rate. Cui-Hung-Wang method, conditional rejection probability method, P-value combination method, conditional error function, and promising zone are common methods used to control FWER. Currently, there are application examples of SSR methods. With the maturation of related theories and the popularization of methods, it is expected to be widely applied in clinical trials, especially in traditional Chinese medicine clinical trials in the future.