General characteristics of the included SRs
| Overall (N=202) | Cochrane SR (N=98) | Non-Cochrane SR (N=104) | p Value* | |
|---|---|---|---|---|
| Number of included trials; median (IQR) | 5 (2–9) | 3 (2–8) | 6 (4–9) | <0.0001 |
| Number of participants in intervention group; median (IQR) | 426.5 (127–1141) | 289 (103–794) | 660 (221–1924) | 0.006 |
| Number of participants in control group; median (IQR) | 418 (117–1026) | 271 (85–657) | 646 (212–1773) | 0.002 |
| AMSTAR score; median (IQR)† | 9 (7–10) | 10 (9–10) | 7 (6–8.5) | <0.0001 |
| Intervention | ||||
| Pharmacological | 130 (64.4%) | 70 (71.4%) | 60 (57.7%) | 0.074 |
| Surgery/invasive procedure | 33 (16.3%) | 15 (15.3%) | 18 (17.3%) | |
| Other | 39 (19.3%) | 13 (13.3%) | 26 (25%) | |
| Type of meta-analysis | ||||
| Standard meta-analysis | 186 (92.1%) | 88 (89.8%) | 98 (94.2%) | 0.30 |
| Metaregression | 18 (8.9%) | 3 (3%) | 15(14.4%) | 0.006 |
| Individual participant data meta-analysis | 7 (3.4%) | 2 (2%) | 5 (4.8%) | 0.45 |
| Other | 10 (5%) | 7 (7.1%) | 3 (2.9%) | 0.204 |
| Evaluation of the risk of bias | <0.0001 | |||
| Using the Cochrane Risk of Bias tool | 94 (46.5%) | 84 (85.7%) | 10 (9.6%) | |
| By dimensions (eg, blinding) | 39 (19.3%) | 8 (8.2%) | 31 (29.8%) | |
| Using Jadad's or other point system scale | 37 (18.3%) | 4 (4.1%) | 33 (31.7%) | |
| Not done | 18 (8.9%) | 0 (0%) | 18 (17.3%) | |
| Used the GRADE approach to rate confidence in effect estimates | 32 (15.8%) | 27 (27.6%) | 5 (4.8%) | <0.0001 |
| Funding | ||||
| For profit source | 7 (3.5%) | 2 (2%) | 5 (4.8%) | 0.45 |
| Source other than for profit | 99 (49%) | 63 (64.3%) | 36 (34.6%) | <0.0001 |
| Not funded | 23 (11.4%) | 9 (9.2%) | 14 (13.5%) | 0.34 |
| Not reported | 72 (35.6%) | 23 (23.5%) | 49 (47%) | 0.0005 |
| Reported industry ties by authors | <0.0001 | |||
| Yes | 37 (18.3%) | 19 (19.4%) | 18 (17.3%) | |
| No | 95 (47.0%) | 60 (61.2%) | 35 (33.7%) | |
| Not reported | 68 (33.7%) | 19 (19.4%) | 49 (47.1%) | |
| Unclear | 2 (1.0%) | 0 (0%) | 2 (1.9%) |
*p Value for the difference between Cochrane and non-Cochrane SRs.
†AMSTAR interpretation: 0–4: low quality; 5–8: moderate quality; 9–11 high quality.
AMSTAR, assessment of multiple systematic reviews; SR, systematic review.