Summary of findings 2. Metformin compared with placebo for preventing type 2 diabetes in adults with mental disorders in low‐ and middle‐income countries.
| Metformin compared with placebo for preventing type 2 diabetes in adults with mental disorders in low‐ and middle‐income countries | ||||||
| Patient or population: Adults with mental disorders in low‐ and middle‐income countries Setting: Hospitals in China and Venezuela Intervention: Metformin Comparison: Placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with metformin | |||||
| Diabetes | No studies identified | |||||
| Drop‐outs (12 to 14 weeks) | Study population | RR 1.22 (0.09 to 16.35) | 158 (3 RCTs) | ⊕⊕⊕⊝ MODERATE 1 2 | ||
| 49 per 1,000 | 11 more per 1,000 (44 fewer to 749 more) | |||||
| Fasting blood glucose (12 to 14 weeks) (endpoint data) | Mean fasting blood glucose was 4.40 to 4.71 mmol/L (normal level) | MD 0.35 lower (0.60 lower to 0.11 lower) | ‐ | 173 (3 RCTs) | ⊕⊕⊕⊝ MODERATE 3 | |
| Fasting blood glucose (12 to 14 weeks) (change from baseline data) | ‐ | MD 0.01 higher (0.21 lower to 0.22 higher) | 91 (2 RCTs) | ⊕⊕⊕⊕ HIGH 4 | ||
| BMI (12 to 14 weeks) | Mean BMI was 23.5 to 25.3 (normal to slightly overweight) | MD 1.37 lower (2.04 lower to 0.7 lower) | ‐ | 264 (5 RCTs) | ⊕⊕⊕⊕ HIGH 4 | |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). BMI: Body mass index; CI: Confidence interval; MD: mean difference; RCT: randomized controlled trial; RR: Risk ratio. | ||||||
| GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1Some unclear risk of bias domains and unbalanced drop‐out in one study, but this is not a concern for this outcome. 2Three relatively small studies with few drop‐outs, which means the estimate has a wide confidence interval. Downgraded one level for imprecision. 3One study shows positive result for metformin while other four studies show no difference. This affects the magnitude and precision of the pooled estimate. Downgraded one level for imprecision. 4One study shows evidence of attrition bias, but removing this result would not substantially change the pooled estimate.