Table 3.
Characteristics of included randomized controlled trials (RCTs) in metformin (MET) for polycystic ovary syndrome (PCOS)
| Features of included RCTs | Number of studies (n = 39) | % |
|---|---|---|
| Year of publication |
|
|
| 1996 to 2001 |
7 |
17.9 |
| 2002 to 2007 |
12 |
30.8 |
| 2008 to February 2013 |
20 |
51.3 |
| Revised CONSORT 2001 |
|
|
| Before |
7 |
17.9 |
| After |
32 |
82.1 |
| Regions in which RCTs were conducted |
|
|
| North America |
6 |
15.4 |
| Europe |
16 |
41.0 |
| Others |
17 |
43.6 |
| Sources of trial funding |
|
|
| Yes |
19 |
48.7 |
| No |
20 |
51.3 |
| Collaboration of different countries |
|
|
| Yes |
8 |
20.5 |
| No |
31 |
79.5 |
| Choice of comparator interventions |
|
|
| Placebo |
16 |
41.0 |
| Sole intervention |
11 |
28.2 |
| MET plus other therapies |
3 |
7.7 |
| Some of above combinations |
9 |
23.1 |
| Journals with most frequently published |
|
|
| The Journal of Clinical Endocrinology & Metabolism |
9 |
23.1 |
| Fertility and Sterility |
7 |
17.9 |
| Human Reproduction |
6 |
15.4 |
| The New England Journal of Medicine |
3 |
7.7 |
| Eleven other journalsa |
14 |
35.9 |
| Impact factors of included journalb |
|
|
| 0.00 to 2.99 |
10 |
25.6 |
| 3.00 to 5.99 |
24 |
61.5 |
| 6.00- | 4 | 10.3 |
Abbreviations: CONSORT, Consolidated Standards of Reporting Trials; MET, metformin; PCOS, polycystic ovary syndrome; RCT, randomized controlled trial.
aEach journal published fewer than three RCTs.
bOne journal (Acta Med Indones) did not have an impact factor.