Objective To systematically evaluate the efficacy and safety of letrozole combined with metformin in the treatment of polycystic ovarian syndrome (PCOS) infertility. Methods PubMed, Cochrane Library, Embase, China National Knowledge Infrastructure, Chongqing VIP, Wanfang, and SinoMed were searched from establishment to December 31, 2022. The literature on randomized controlled trials of letrozole combined with metformin in the treatment of PCOS infertility were included. RevMan 5.4 software was used for meta-analysis. Results A total of 29 articles including 3226 subjects were included, with trial group of 1614 treated with letrozole combined with metformin, and control group of 1612 treated with letrozole alone. The meta-analysis results showed that the clinical pregnancy rate [relative risk (RR)=1.76, 95% confidence interval (CI) (1.61, 1.92)], induced ovulation rate [RR=1.22, 95%CI (1.17, 1.28)], and number of dominant follicles [mean difference (MD)=1.15, 95%CI (0.86, 1.43)] in the trial group were higher than those in the control group (P<0.05). The follicle growth time [MD=−5.41 d, 95%CI (−6.03, −4.80) d], estradiol level [MD=−7.57 pmol/L, 95%CI (−10.59, −4.56) pmol/L], luteinizing hormone level [MD=−2.27 U/L, 95%CI (−2.59, −1.95) U/L], testosterone level [MD=−1.29 nmol/L, 95%CI (−1.74, −0.85) nmol/L], fasting blood glucose level [MD=−0.91 mmol/L, 95%CI (−1.71, −0.65) mmol/L], fasting insulin level [MD=−25.93 pmol/L, 95%CI (−29.06, −22.80) pmol/L], insulin resistance index [MD=−1.40, 95%CI (−1.61, −1.19)], and the incidence of ovarian hyperstimulation syndrome [RR=0.44, 95%CI (0.22, 0.88)] in the trial group were lower than those in the control group (P<0.05). There was no statistically significant difference in follicle stimulating hormone level, incidence of adverse reactions, and spontaneous abortion rates between the two groups (P>0.05). Conclusion Existing evidence suggests that compared to using trazole alone, the combination of letrozole and metformin can improve ovulation induction and pregnancy outcomes in patients with PCOS infertility. The combination of the two drugs can reduce levels of estradiol, testosterone, and luteinizing hormone in patients, while effectively reducing the incidence of ovarian hyperstimulation syndrome.
Traditional Chinese Medicine (TCM) clinical practice guidelines play essential roles in the development of TCM. However, the existing TCM guidelines are not effectively used in clinic. Based on this phenomenon, this article addresses the characteristics of clinical practice guidelines of TCM, and analyzes its status, problems and resolutions, providing feasible suggestions for the development of high-quality clinical practice guidelines of TCM which are in accordance with clinical practice.
It is very important to develop and revise expert panel consensus on Chinese patent medical clinical application. The contents of the expert panel consensus include determination of the subject, clarity of the application scope, indications, dosage and administration, and safety of Chinese patent medicine. In the process, clinical researchers establish project team, formulate clinical management questions, select the outcome index, retrieve and make the evidence, and develop expert consensus with consensus methods strictly according to the requirements of methodology.