Summary of findings 3. Metformin compared with clomiphene citrate for women with polycystic ovary syndrome.
| Metformin compared with clomiphene citrate for women with polycystic ovary syndrome | ||||||
| Population: women with polycystic ovary syndrome Setting: outpatient Intervention: metformin Comparison: clomiphene citrate | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with CC | Risk with metformin | |||||
|
Live birth rate per woman aParticipants with BMI < 30 kg/m2 or ≤ 32 kg/m2 |
256 per 1000 | 371 per 1000 (256 to 503) |
OR 1.71 (1.00 to 2.94) | 241 (3 studies) |
⊕⊝⊝⊝ very lowb,c,d |
High heterogeneity (I2 = 78%) 76 events |
|
Live birth rate per woman aParticipants with BMI ≥ 30 kg/m2 |
216 per 1000 | 76 per 1000 (45 to 125) |
OR 0.30 (0.17 to 0.52) |
500 (2 studies) |
⊕⊝⊝⊝ very lowb,c,d | 73 events |
|
Adverse events (gastrointestinal) |
Not reported by any of the included studies | |||||
| Clinical pregnancy rate per womanaParticipants with BMI < 30 kg/m2 or ≤ 32 kg/m2 | 258 per 1000 | 352 per 1000 (270 to 444) | OR 1.56 (1.06 to 2.29) | 530 (6 studies) | ⊕⊕⊝⊝ lowb,e | 160 events |
|
Clinical pregnancy rate per woman aParticipants with BMI ≥ 30 kg/m2 |
276 per 1000 | 115 per 1000 (74 to 173) | OR 0.34 (0.21 to 0.55) | 500 (2 studies) | ⊕⊕⊝⊝ lowb,c | 98 events |
|
Ovulation rate per woman fParticipants with BMI < 30 kg/m2 |
650 per 1000 | 597 per 1000 (491 to 699) | OR 0.80 (0.52 to 1.25) | 352 (5 studies) | ⊕⊕⊝⊝ lowb,c | 220 events |
|
Ovulation rate per woman fParticipants with BMI ≥ 30 kg/m2 |
516 per 1000 | 236 per 1,000 (176 to 314) | OR 0.29 (0.20 to 0.43) | 500 (2 studies) | ⊕⊕⊝⊝ lowb,c | 188 events |
|
Miscarriage rate per woman aParticipants with BMI < 30 kg/2 |
57 per 1000 | 83 per 1000 (36 to 182) | OR 1.51 (0.62 to 3.71) | 281 (4 studies) |
⊕⊕⊝⊝ lowb,c | 20 events Miscarriage rate per pregnancy: OR 1.02 (0.41 to 2.54) |
|
Miscarriage rate per woman aParticipants with BMI ≥ 30 kg/m2 |
64 per 1000 | 40 per 1000 (18 to 86) | OR 0.61 (0.27 to 1.38) | 500 (2 studies) | ⊕⊕⊝⊝ lowb,c | 26 events; only 1 study with events Miscarriage rate per pregnancy: OR 1.92 (0.72 to 5.12) |
| *The risk in the intervention group (and its 95% confidence interval) is based on the median risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; OR: odds ratio | ||||||
| GRADE Working Group grades of evidence High quality: further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate. | ||||||
aData subgrouped by BMI, as pooling of BMI groups resulted in high heterogeneity (I2 > 85%) with differing directions of effect. bEvidence downgraded one level for risk of bias. cEvidence downgraded one level for serious imprecision: low event rate and/or wide confidence intervals. dEvidence downgraded for high heterogeneity. eEvidence downgraded for serious imprecision; many small studies with wide confidence intervals. fData subgrouped by BMI, as pooling of BMI groups resulted in high heterogeneity (I2 = 74%), though direction of effect was consistent.