Table. Summary of Outcomes.
| Outcome | Assumed risk among control group study participants per 1000 patientsa | Assumed moderate risk among control group per 1000 patientsa | Corresponding risk among metformin group study participants per 1000 patients (95% CI)a | Corresponding moderate risk among metformin group per 1000 patients (95% CI)a | Relative effect, OR (95% CI) | Participants, No. (studies, No.) | Quality of evidenceb |
|---|---|---|---|---|---|---|---|
| Risk of OHSS | |||||||
| All participants | 179 | 125 | 86 (52-137) | 58 (34-94) | 0.43 (0.25-0.73) | 947 (11) | High |
| Participants with BMI ≥26 | 167 | 165 | 48 (24-93) | 47 (23-92) | 0.25 (0.12-0.51) | 482 (6) | High |
| Participants with BMI <26 | 200 | 147 | 140 (72-259) | 101 (51-194) | 0.65 (0.31-1.40) | 425 (4) | High |
| Clinical pregnancy rate | |||||||
| All participants | 335 | 304 | 385 (293-484) | 351 (264-448) | 1.24 (0.82-1.86) | 1015 (11) | Moderatec |
| Participants with BMI ≥26 | 280 | 219 | 400 (304-503) | 324 (239-422) | 1.71 (1.12-2.60) | 482 (6) | High |
| Participants with BMI <26 | 385 | 364 | 305 (235-484) | 330 (219-462) | 0.86 (0.49-1.50) | 533 (5) | Moderatec |
| Live birth rate | |||||||
| All participants | 303 | 291 | 349 (244-471) | 335 (233-456) | 1.23 (0.74-2.04) | 811 (8) | Moderatec |
| Participants with BMI ≥26 | 276 | 260 | 371 (268-487) | 353 (252-467) | 1.55 (0.96-2.49) | 386 (4) | High |
| Participants with BMI <26 | 329 | 291 | 322 (170-523) | 285 (147-479) | 0.97 (0.42-2.24) | 425 (4) | Moderatec |
Abbreviation: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); OR, odds ratio.
The assumed risk is the median control group risk across studies. The corresponding risk and its 95% CI are based on the assumed risk in the control group and the relative effect (ie, OR) and its 95% CI.
Quality of evidence was based on the GRADE Working Group grades of evidence, as follows: high, further research is very unlikely to change our confidence in the estimate of effect; moderate, further research is likely to have an important effect on our confidence in the estimate of effect and may change the estimate; low, further research is very likely to have an important effect on our confidence in the estimate of effect and is likely to change the estimate; very low, we are very uncertain about the estimate.
Heterogeneity was high, with I2 greater than 50%.