Letrozole versus clomiphene citrate in polycystic ovary syndrome: systematic review and meta-analysis

The objective of the present systematic review and meta-analysis was to examine the literature and to identify the results of randomized controlled trials (RCTs) comparing the use of letrozole to clomiphene citrate (CC) for ovulation induction in patients with polycystic ovary syndrome (PCOS). An exhaustive electronic literature search was performed using the MEDLINE and EMBASE databases until October 2014. Seven prospective RCTs comparing the use of letrozole to CC in PCOS patients met the inclusion criteria. Overall, the seven included studies accounted for 1833 patients (906 in the letrozole group and 927 in the CC group) and for 4999 ovulation induction cycles (2455 in the letrozole group and 2544 in the CC group). Five of the included studies reported data on live birth rates. There was a statistically significant increase in the live birth and pregnancy rates in the letrozole group when compared to the CC group, with a relative risk (RR) = 1.55 (95% confidence interval (CI): 1.26–1.90; <i>I²</i>= 0%) and RR = 1.38 (95% CI: 1.05–1.83; <i>I²</i>= 61%), respectively. There were no differences in the multiple pregnancy, miscarriage and ovulation rates between the two groups. Our study found that letrozole is superior to CC when considering the live birth and pregnancy rates in patients with PCOS.

本项系统评价与荟萃分析的研究目的为检索相关文献，明确对比来曲唑（letrozole）与枸橼酸氯米芬（clomiphene citrate，CC）用于多囊卵巢综合征（polycystic ovary syndrome，PCOS）患者促排卵治疗效果的随机对照试验（randomized controlled trials，RCTs）结果。研究团队于2014年10月前，通过MEDLINE与EMBASE数据库开展了全面的电子文献检索。最终共有7项对比来曲唑与枸橼酸氯米芬应用于PCOS患者的前瞻性RCTs符合纳入标准。纳入的7项研究共计涵盖1833例患者（来曲唑组906例，枸橼酸氯米芬组927例），涉及4999个促排卵周期（来曲唑组2455个，枸橼酸氯米芬组2544个）。其中5项研究报告了活产率相关数据。与枸橼酸氯米芬组相比，来曲唑组的活产率与妊娠率均存在统计学意义上的显著提升，相对风险（relative risk，RR）分别为1.55（95%置信区间（confidence interval，CI）：1.26–1.90；I²=0%）与1.38（95%CI：1.05–1.83；I²=61%）。两组在多胎妊娠率、流产率及排卵率方面均无显著差异。本研究结果表明，针对PCOS患者，若以活产率与妊娠率作为疗效评估指标，来曲唑的治疗效果优于枸橼酸氯米芬。