Table 1. Included Studies.
| Paper1 | Duration2 | Country | Setting3 | Diagnostic tool4 | Diagnoses | Participants already on clozapine (Y/N) | Presence of Psychosocial weight loss intervention | Mean Age (SD) for Metformin / Placebo5 | Mean baseline weight (SD) for Metformin / Placebo5 | Number of Participants Metformin / Placebo | Number Completed Metformin / Placebo | Male % | Mean Daily Metformin dose | Allocation6 | Blinding7 | Randomisation8 | Primary Outcome9 | Reporting10 | ITT11 | Other Bias12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Carizzo et al 200913 | 14 w | Venezuela | C | DSM-IV | Schizophrenia Bipolar I | Y | No | 39.6 (9.7) / 38.3 (8.7) | 82.2 (20.9) / 77.1 (15.8) | 31 / 30 | 24 / 30 | NS | 1000 mg | Yes | Double | Yes | Yes | Yes | No | No |
| Chen et al 201313 | 24 w | Taiwan | H+C | DSM-IV | Schizophrenia Schizoaffective | Y | No | 41.8 (7.2) / 41.4 (10.2) | 69.1 (13.7) / 67.2 (9.6) | 28 / 27 | 28 / 27 | 51% | 1500 mg | Yes | Double | Yes | Yes | Yes | Yes | No |
| Hebrani et al 201513 | 20 w | Iran | H | DSM-IV-TR | Schizophrenia | Y | No | 47.2 (10.4) / 45.8 (10.2) | 78.44 (13.4) / 70.50 (17.02) | 30 / 30 | 19 / 18 | 46% | 1000 mg | NS | Double | Yes | Yes | Yes | No | No |
| Wu et al 200813 | 12 w | China | H | DSM-IV | Schizophrenia | Y | No14 | 26.8 / 25.815 | 64.7 / 64.615 | 11 / 1016 (Clozapine subgroup) | 11 / 1016 (Clozapine subgroup) | NS | 750 mg | Yes | Double | Yes | Yes | Yes | Yes | No |
| Wu et al 201213 | 6 m | China | H | DSM-IV | Schizophrenia | Y | No | 25.7 (4.8) / 27.1 (4.2) 15 | 56.6 (5.2) / 56.8 (5.6) 15 | 2 / 116 Clozapine subgroup) | 2 / 116 (Clozapine subgroup) | 0% | 1000 mg | Yes | Double | Yes | Yes | Yes | Yes | No |
| Liu 201217 | 12 w | China | H | CCMD-3 | Schizophrenia | NS | No | 31.5 (8.6) / 29.8 (6.5) | 60.5 (8.3) / 62.3 (9.6) | 50 / 50 | 50 / 50 | 61% | 250–50018 mg-d | No | No | Yes | Yes | Yes | No | FNS |
| Wang 200917 | 6 m | China | H | CCMD-3 | Schizophrenia | Y | For both Metformin and Placebo | 38 (16) / 37 (15) | NS | 71 / 71 | 69 / 67 | 63% | 1500 mg | No | No | Yes | Yes | Yes | No | FNS |
| Wu et al 201413 | 12 w | China | H | CCMD-3 | Schizophrenia | Y | No | 27.22 (6.40) / 25.80 (6.23) | 61.8 (7.3) / 61.9 (7.4) | 36 / 36 | 36 / 36 | 59% | 1000mg | No | No | Yes | Yes | Yes | No | FNS |
NS = not stated
1. Lead author and year of publication
2. w = weeks, m = months
3. H = Hospital, C = Community
4. DSM = Diagnostic and Statistical Manual CCMD-3 = Chinese classification of mental disorder
5. SD = Standard Deviation,
6. Adequate allocation concealment
7. Single is to assessor only
8. Adequate Random Sequence Generation
9. Primary Outcome Measures were pre-specified and reported
10. Completeness of outcome reporting
11. ITT = Intention to Treat analysis
12. Were other potential sources of bias present. FNS = funding source not specified
13. Identified through search of western databases
14. Only data for the participants in the metformin and placebo without psychosocial health intervention groups were included.
15. Mean and SD for participants on all anti-psychotics, not just participants on clozapine
16. Only participants on clozapine included in meta-analysis
17. Identified through search of Chinese databases
18. Range, no mean reported