Clomiphene citrate alone, in combination with metformin or in combination with pioglitazone as first line therapy in induction of ovulation in infertile women with polycystic ovary syndrome, a randomized controlled trial

SGLT-2 inhibitors enhance the effect of metformin to ameliorate hormonal changes and inflammatory markers in a rat PCOS model

Polycystic ovary syndrome (PCOS) is a common endocrine, reproductive, and metabolic disorder affecting females. The management of PCOS is challenging and current interventions are not enough to deal with all consequences of this syndrome. We explored the beneficial effect of combined sodium glucose co transporter-2 inhibitor (SGLT-2i); (empagliflozin) and metformin on hormonal and metabolic parameters in an animal model of PCOS and insulin resistance (IR). Forty adult female Wistar rats divided into five groups: control, PCOS-IR, PCOS-IR treated with metformin, PCOS-IR treated with empagliflozin, and PCOS-IR treated with combined metformin and empagliflozin. Single modality treatment with metformin or empagliflozin yielded significant improvement in body mass index, insulin resistance, lipid profile, sex hormones, inflammatory markers, and ovarian cystic follicles. Combined metformin with empagliflozin expressed further significant improvement in sex hormones, inflammatory markers with disappearance of ovarian cystic follicles. The superior significant improvement with combined treatment over the single modality was in line with significant improvement in the ovarian AMPKα-SIRT1 expression.

To share or not to share data: how valid are trials evaluating first-line ovulation induction for polycystic ovary syndrome?

BACKGROUND

In our recent individual participant data (IPD) meta-analysis evaluating the effectiveness of first-line ovulation induction for polycystic ovary syndrome (PCOS), IPD were only available from 20 studies of 53 randomized controlled trials (RCTs). We noticed that the summary effect sizes of meta-analyses of RCTs without IPD sharing were different from those of RCTs with IPD sharing. Granting access to IPD for secondary analysis has implications for promoting fair and transparent conduct of RCTs. It is, however, still common for authors to choose to withhold IPD, limiting the impact of and confidence in the results of RCTs and systematic reviews based on aggregate data.

OBJECTIVE AND RATIONALE

We performed a meta-epidemiologic study to elucidate if RCTs without IPD sharing have lower quality and more methodological issues than those with IPD sharing in an IPD meta-analysis evaluating first-line ovulation induction for PCOS.

SEARCH METHODS

We included RCTs identified for the IPD meta-analysis. We dichotomized RCTs according to whether they provided IPD (shared group) or not (non-shared group) in the IPD meta-analysis. We restricted RCTs to full-text published trials written in English.

We assessed and compared RCTs in the shared and non-shared groups on the following criteria: Risk of Bias (RoB 2.0), GRADE approach, adequacy of trial registration; description of statistical methods and reproducibility of univariable statistical analysis; excessive similarity or difference in baseline characteristics that is not compatible with chance; and other miscellaneous methodological issues.

OUTCOMES

In total, 45 trials (8697 women) were included in this study. IPD were available from 17 RCTs and 28 trials were categorized as the non-shared IPD group. Pooled risk rates obtained from the shared and non-shared groups were different. Overall low risk of bias was associated with 13/17 (76%) of shared RCTs versus 7/28 (25%) of non-shared RCTs. For RCTs that started recruitment after 1 July 2005, adequate trial registration was found in 3/9 (33%) of shared IPD RCTs versus 0/16 (0%) in non-shared RCTs. In total, 7/17 (41%) of shared RCTs and 19/28 (68%) of non-shared RCTs had issues with the statistical methods described. The median (range) of inconsistency rate per study, between reported and reproduced analyses for baseline variables, was 0% (0–92%) (6 RCTs applicable) in the shared group and 54% (0–100%) (13 RCTs applicable) in the non-shared group. The median (range) of inconsistency rate of univariable statistical results for the outcome(s) per study was 0% (0–63%) (14 RCTs applicable) in the shared group and 44% (0–100%) (24 RCTs applicable) in the non-shared group. The distributions of simulation-generated P-values from comparisons of baseline continuous variables between intervention and control arms suggested that RCTs in the shared group are likely to be consistent with properly conducted randomization (P = 0.163), whereas this was not the case for the RCTs in the non-shared group (P = 4.535 × 10−8).

WIDER IMPLICATIONS

IPD meta-analysis on evaluating first-line ovulation induction for PCOS preserves validity and generates more accurate estimates of risk than meta-analyses using aggregate data, which enables more transparent assessments of benefits and risks. The availability of IPD and the willingness to share these data may be a good indicator of quality, methodological soundness and integrity of RCTs when they are being considered for inclusion in systematic reviews and meta-analyses.

First-line ovulation induction for polycystic ovary syndrome: an individual participant data meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most frequent cause of anovulatory infertility. In women with PCOS, effective ovulation induction serves as an important first-line treatment for anovulatory infertility. Individual participant data (IPD) meta-analysis is considered as the gold standard for evidence synthesis which provides accurate assessments of outcomes from primary randomised controlled trials (RCTs) and allows additional analyses for time-to-event outcomes. It also facilitates treatment-covariate interaction analyses and therefore offers an opportunity for personalised medicine.

OBJECTIVE AND RATIONALE

We aimed to evaluate the effectiveness of different ovulation induction agents, in particular letrozole alone and clomiphene citrate (CC) plus metformin, as compared to CC alone, as the first-line choice for ovulation induction in women with PCOS and infertility, and to explore interactions between treatment and participant-level baseline characteristics.

SEARCH METHODS

We searched electronic databases including MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials up to 20 December 2018. We included RCTs comparing the following interventions with each other or placebo/no treatment in women with PCOS and infertility: CC, metformin, CC plus metformin, letrozole, gonadotrophin and tamoxifen. We excluded studies on treatment-resistant women. The primary outcome was live birth. We contacted the investigators of eligible RCTs to share the IPD and performed IPD meta-analyses. We assessed the risk of bias by using the Cochrane risk of bias tool for RCTs.

OUTCOMES

IPD of 20 RCTs including 3962 women with PCOS were obtained. Six RCTs compared letrozole and CC in 1284 women. Compared with CC, letrozole improved live birth rates (3 RCTs, 1043 women, risk ratio [RR] 1.43, 95% confidence interval [CI] 1.17-1.75, moderate-certainty evidence) and clinical pregnancy rates (6 RCTs, 1284 women, RR 1.45, 95% CI 1.23-1.70, moderate-certainty evidence) and reduced time-to-pregnancy (6 RCTs, 1235 women, hazard ratio [HR] 1.72, 95% CI 1.38-2.15, moderate-certainty evidence). Meta-analyses of effect modifications showed a positive interaction between baseline serum total testosterone levels and treatment effects on live birth (interaction RR 1.29, 95% CI 1.01-1.65). Eight RCTs compared CC plus metformin to CC alone in 1039 women. Compared with CC alone, CC plus metformin might improve clinical pregnancy rates (8 RCTs, 1039 women, RR 1.18, 95% CI 1.00-1.39, low-certainty evidence) and might reduce time-to-pregnancy (7 RCTs, 898 women, HR 1.25, 95% CI 1.00-1.57, low-certainty evidence), but there was insufficient evidence of a difference on live birth rates (5 RCTs, 907 women, RR 1.08, 95% CI 0.87-1.35, low-certainty evidence). Meta-analyses of effect modifications showed a positive interaction between baseline insulin levels and treatment effects on live birth in the comparison between CC plus metformin and CC (interaction RR 1.03, 95% CI 1.01-1.06).

WIDER IMPLICATIONS

In women with PCOS, letrozole improves live birth and clinical pregnancy rates and reduces time-to-pregnancy compared to CC and therefore can be recommended as the preferred first-line treatment for women with PCOS and infertility. CC plus metformin may increase clinical pregnancy and may reduce time-to-pregnancy compared to CC alone, while there is insufficient evidence of a difference on live birth. Treatment effects of letrozole are influenced by baseline serum levels of total testosterone, while those of CC plus metformin are affected by baseline serum levels of insulin. These interactions between treatments and biomarkers on hyperandrogenaemia and insulin resistance provide further insights into a personalised approach for the management of anovulatory infertility related to PCOS.

Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterised by infrequent or absent ovulation, and high levels of androgens and insulin (hyperinsulinaemia). Hyperinsulinaemia occurs secondary to insulin resistance and is associated with an increased biochemical risk profile for cardiovascular disease and an increased prevalence of diabetes mellitus. Insulin-sensitising agents such as metformin may be effective in treating PCOS-related anovulation. This is an update of Morley 2017 and only includes studies on metformin.

OBJECTIVES

To evaluate the effectiveness and safety of metformin in combination with or in comparison to clomiphene citrate (CC), letrozole and laparoscopic ovarian drilling (LOD) in improving reproductive outcomes and associated gastrointestinal side effects for women with PCOS undergoing ovulation induction.

SEARCH METHODS

We searched the following databases from inception to December 2018: Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL. We searched registers of ongoing trials and reference lists from relevant studies.

SELECTION CRITERIA

We included randomised controlled trials of metformin compared with placebo, no treatment, or in combination with or compared with CC, letrozole and LOD for women with PCOS subfertility.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility and bias. Primary outcomes were live birth rate and gastrointestinal adverse effects. Secondary outcomes included other pregnancy outcomes and ovulation. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I² statistic and reported quality of the evidence for primary outcomes and reproductive outcomes using GRADE methodology.

MAIN RESULTS

We included 41 studies (4552 women). Evidence quality ranged from very low to moderate based on GRADE assessment. Limitations were risk of bias (poor reporting of methodology and incomplete outcome data), imprecision and inconsistency. Metformin versus placebo or no treatment The evidence suggests that metformin may improve live birth rates compared with placebo (OR 1.59, 95% CI 1.00 to 2.51; I² = 0%; 4 studies, 435 women; low-quality evidence). For a live birth rate of 19% following placebo, the live birth rate following metformin would be between 19% and 37%. The metformin group probably experiences more gastrointestinal side effects (OR 4.00, 95% CI 2.63 to 6.09; I² = 39%; 7 studies, 713 women; moderate-quality evidence). With placebo, the risk of gastrointestinal side effects is 10% whereas with metformin this risk is between 22% and 40%. There are probably higher rates of clinical pregnancy (OR 1.98, 95% CI 1.47 to 2.65; I² = 30%; 11 studies, 1213 women; moderate-quality evidence). There may be higher rates of ovulation with metformin (OR 2.64, 95% CI 1.85 to 3.75; I² = 61%; 13 studies, 684 women; low-quality evidence). We are uncertain about the effect on miscarriage rates (OR 1.08, 95% CI 0.50 to 2.35; I² = 0%; 4 studies, 748 women; low-quality evidence). Metformin plus CC versus CC alone We are uncertain if metformin plus CC improves live birth rates compared to CC alone (OR 1.27, 95% CI 0.98 to 1.65; I² = 28%; 10 studies, 1219 women; low-quality evidence), but gastrointestinal side effects are probably more common with combined therapy (OR 4.26, 95% CI 2.83 to 6.40; I² = 8%; 6 studies, 852 women; moderate quality evidence). The live birth rate with CC alone is 24%, which may change to between 23% to 34% with combined therapy. With CC alone, the risk of gastrointestinal side effects is 9%, which increases to between 21% to 37% with combined therapy. The combined therapy group probably has higher rates of clinical pregnancy (OR 1.62, 95% CI 1.32 to 1.99; I² = 31%; 19 studies, 1790 women; moderate-quality evidence). The combined group may have higher rates of ovulation (OR 1.65, 95% CI 1.35 to 2.03; I² = 63%;21 studies, 1568 women; low-quality evidence). There was no clear evidence of an effect on miscarriage (OR 1.35, 95% CI 0.91 to 2.00; I² = 0%; 10 studies, 1206 women; low-quality evidence). Metformin versus CC When all studies were combined, findings for live birth were inconclusive and inconsistent (OR 0.71, 95% CI 0.49 to 1.01; I² = 86%; 5 studies, 741 women; very low-quality evidence). In subgroup analysis by obesity status, obese women had a lower birth rate in the metformin group (OR 0.30, 95% CI 0.17 to 0.52; 2 studies, 500 women), while the non-obese group showed a possible benefit from metformin, with high heterogeneity (OR 1.71, 95% CI 1.00 to 2.94; I² = 78%, 3 studies, 241 women; very low-quality evidence). However, due to the very low quality of the evidence we cannot draw any conclusions. Among obese women taking metformin there may be lower rates of clinical pregnancy (OR 0.34, 95% CI 0.21 to 0.55; I² = 0%; 2 studies, 500 women; low-quality evidence) and ovulation (OR 0.29, 95% CI 0.20 to 0.43; I² = 0%; 2 studies, 500 women; low-quality evidence) while among non-obese women, the metformin group may have more pregnancies (OR 1.56, 95% CI 1.06 to 2.29; I² = 26%; 6 studies, 530 women; low-quality evidence) and no clear difference in ovulation rates (OR 0.80, 95% CI 0.52 to 1.25; I² = 0%; 5 studies, 352 women; low-quality evidence). We are uncertain whether there is a difference in miscarriage rates between the groups (overall: OR 0.92, 95% CI 0.51 to 1.66; I² = 36%; 6 studies, 781 women; low-quality evidence) and no studies reported gastrointestinal side effects.

AUTHORS' CONCLUSIONS

Our updated review suggests that metformin may be beneficial over placebo for live birth however, more women probably experience gastrointestinal side effects. We are uncertain if metformin plus CC improves live birth rates compared to CC alone, but gastrointestinal side effects are probably increased with combined therapy. When metformin was compared with CC, data for live birth were inconclusive, and the findings were limited by lack of evidence. Results differed by body mass index (BMI), emphasising the importance of stratifying results by BMI. No studies reported gastrointestinal side effects in this comparison. Due to the low quality of the evidence, we are uncertain of the effect of metformin on miscarriage in all three comparisons.

Metformin and pioglitazone combination therapy ameliorate polycystic ovary syndrome through AMPK/PI3K/JNK pathway

Polycystic ovary syndrome (PCOS) is a common gynecological endocrine disorder, which results in health problems such as menstrual disorders, hyperandrogenism and persistent anovulation. Hyperandrogenism and insulin resistance are the basic characteristics of PCOS. To investigate the combined effect of metformin and pioglitazone on POCS and the potential mechanisms, a rat model of PCOS was established by intramuscular injection of estradiol valerate (EV). The effect of metformin and pioglitazone monotherapy or combination therapy in control rats and PCOS rats was evaluated, involving the testosterone level, follicular development and insulin resistance. The potential mechanism for the therapeutic effect of metformin and pioglitazone on POCS was explored through using three inhibitors of the 5'adenosine monophosphate-activated protein kinase (AMPK)/phosphoinositide-3 kinase (PI3K)/c-Jun N-terminal kinase (JNK) pathway (Compound C, Wortmannin and SP600125). The results showed that EV-induced PCOS rats demonstrated hyperandrogenemia, hyperinsulinemia and follicular dysplasia. Metformin or pioglitazone monotherapy significantly suppressed the high level of testosterone, reduced the raised percentage of cystic follicles and primary follicles, promoted the number of early antral follicles, and markedly decreased the high concentration of fasting insulin and homeostatic model assessment for insulin resistance index in PCOS rats. In addition, metformin and pioglitazone combination therapy demonstrated greater efficacy than its individual components. Furthermore, individual or joint treatment with metformin and pioglitazone affected the phosphorylation level of JNK in PCOS rats. Compound C and Wortmannin eliminated the effect of metformin and pioglitazone combination therapy on improving the follicular growth in PCOS rats, whereas SP600125 treatment enhanced this combination therapy effect. These data suggested that metformin and pioglitazone combination therapy demonstrated great efficacy in ameliorating PCOS through regulating the AMPK/PI3K/JNK pathway.

Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterised by infrequent or absent ovulation, and high levels of androgens and insulin (hyperinsulinaemia). Hyperinsulinaemia occurs secondary to insulin resistance and is associated with increased risk of cardiovascular disease and diabetes mellitus. Insulin-sensitising agents such as metformin may be effective in treating PCOS-related anovulation.

OBJECTIVES

To evaluate the effectiveness and safety of insulin-sensitising drugs in improving reproductive and metabolic outcomes for women with PCOS undergoing ovulation induction.

SEARCH METHODS

We searched the following databases from inception to January 2017: Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL. We searched registers of ongoing trials and reference lists from relevant studies.

SELECTION CRITERIA

We included randomised controlled trials of insulin-sensitising drugs compared with placebo, no treatment, or an ovulation-induction agent for women with oligo and anovulatory PCOS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility and bias. Primary outcomes were live birth rate and gastrointestinal adverse effects. Secondary outcomes included other pregnancy outcomes, menstrual frequency and metabolic effects. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I2 statistic and reported quality of the evidence for primary outcomes using GRADE methodology.

MAIN RESULTS

We assessed the interventions metformin, clomiphene citrate, metformin plus clomiphene citrate, D-chiro-inositol, rosiglitazone and pioglitazone. We compared these with each other, placebo or no treatment. We included 48 studies (4451 women), 42 of which investigated metformin (4024 women). Evidence quality ranged from very low to moderate. Limitations were risk of bias (poor reporting of methodology and incomplete outcome data), imprecision and inconsistency. Metformin versus placebo or no treatmentThe evidence suggests that metformin may improve live birth rates compared with placebo (OR 1.59, 95% CI 1.00 to 2.51, 4 studies, 435 women, I2 = 0%, low-quality evidence). The metformin group experienced more gastrointestinal side effects (OR 4.76, 95% CI 3.06 to 7.41, 7 studies, 670 women, I2 = 61%, moderate-quality evidence) but had higher rates of clinical pregnancy (OR 1.93, 95% CI 1.42 to 2.64, 9 studies, 1027 women, I2 = 43%, moderate-quality evidence), ovulation (OR 2.55, 95% CI 1.81 to 3.59, 14 studies, 701 women, I2 = 58%, moderate-quality evidence) and menstrual frequency (OR 1.72, 95% CI 1.14 to 2.61, 7 studies, 427 women, I2 = 54%, low-quality evidence). There was no clear evidence of a difference in miscarriage rates (OR 1.08, 95% CI 0.50 to 2.35, 4 studies, 748 women, I2 = 0%, low-quality evidence). Metformin plus clomiphene citrate versus clomiphene citrate alone There was no conclusive evidence of a difference between the groups in live birth rates (OR 1.21, 95% CI 0.92 to 1.59, 9 studies, 1079 women, I2 = 20%, low-quality evidence), but gastrointestinal side effects were more common with combined therapy (OR 3.97, 95% CI 2.59 to 6.08, 3 studies, 591 women, I2 = 47%, moderate-quality evidence). However, the combined therapy group had higher rates of clinical pregnancy (OR 1.59, 95% CI 1.27 to 1.99, 16 studies, 1529 women, I2 = 33%, moderate-quality evidence) and ovulation (OR 1.57, 95% CI 1.28 to 1.92, 21 studies, 1624 women, I2 = 64%, moderate-quality evidence). There was a statistically significant difference in miscarriage rate per woman, with higher rates in the combined therapy group (OR 1.59, 95% CI 1.03 to 2.46, 9 studies, 1096 women, I2 = 0%, low-quality evidence) but this is of uncertain clinical significance due to low-quality evidence, and no clear difference between groups when we analysed miscarriage per pregnancy (OR 1.30, 95% CI 0.80 to 2.12, 8 studies; 400 pregnancies, I2 = 0%, low-quality evidence). Metformin versus clomiphene citrateWhen all studies were combined, findings for live birth were inconclusive and inconsistent (OR 0.71, 95% CI 0.49 to 1.01, 5 studies, 741 women, I2 = 86%, very low-quality evidence). In subgroup analysis by obesity status, obese women had a lower birth rate in the metformin group (OR 0.30, 95% CI 0.17 to 0.52, 2 studies, 500 women, I2 = 0%, very low-quality evidence), while data from the non-obese group showed a possible benefit from metformin, with high heterogeneity (OR 1.71, 95% CI 1.00 to 2.94, 3 studies, 241 women, I2 = 78%, very low-quality evidence). Similarly, among obese women taking metformin there were lower rates of clinical pregnancy (OR 0.34, 95% CI 0.21 to 0.55, 2 studies, 500 women, I2 = 0%, very low-quality evidence) and ovulation (OR 0.29, 95% CI 0.20 to 0.43 2 studies, 500 women, I2 = 0%, low-quality evidence) while among non-obese women, the metformin group had more pregnancies (OR 1.56, 95% CI 1.05 to 2.33, 5 studies, 490 women, I2 = 41%, very low-quality evidence) and no clear difference in ovulation rates (OR 0.81, 95% CI 0.51 to 1.28, 4 studies, 312 women, low-quality evidence, I2=0%). There was no clear evidence of a difference in miscarriage rates (overall: OR 0.92, 95% CI 0.50 to 1.67, 5 studies, 741 women, I2 = 52%, very low-quality evidence). D-chiro-inositol (2 studies), rosiglitazone (1 study) or pioglitazone (1 study) versus placebo or no treatmentWe were unable to draw conclusions regarding other insulin-sensitising drugs as no studies reported primary outcomes.

AUTHORS' CONCLUSIONS

Our updated review suggests that metformin alone may be beneficial over placebo for live birth, although the evidence quality was low. When metformin was compared with clomiphene citrate, data for live birth were inconclusive, and our findings were limited by lack of evidence. Results differed by body mass index (BMI), emphasising the importance of stratifying results by BMI. An improvement in clinical pregnancy and ovulation suggests that clomiphene citrate remains preferable to metformin for ovulation induction in obese women with PCOS.An improved clinical pregnancy and ovulation rate with metformin and clomiphene citrate versus clomiphene citrate alone suggests that combined therapy may be useful although we do not know whether this translates into increased live births. Women taking metformin alone or with combined therapy should be advised that there is no evidence of increased miscarriages, but gastrointestinal side effects are more likely.