Table 2.
General characteristics of systematic reviews and meta-analyses
| Characteristics | No. (%) of articles (n=185) | OR (95% CI) | ||
| Total (%) | Abstract contains spin | Unadjusted | Adjusted | |
| Article mentions adherence to PRISMA | ||||
| No | 106 (17.8) | 36 (19.5) | 1 (Reference) | 1 (Reference) |
| Yes | 79 (42.7) | 23 (12.4) | 0.67 (0.34 to 1.32) | 0.42 (0.16 to 1.07) |
| Publishing journal recommends adherence to PRISMA | ||||
| No | 124 (67.0) | 43 (23.2) | 1 (Reference) | 1 (Reference) |
| Yes | 61 (33) | 16 (8.6) | 0.80 (0.43 to 1.50) | 0.65 (0.29 to 1.46) |
| Funding source | ||||
| Not funded | 44 (23.8) | 16 (8.6) | 1 (Reference) | 1 (Reference) |
| Industry | 11 (5.9) | 4 (2.2) | 1.00 (0.25 to 3.95) | 1.27 (0.23 to 7.04) |
| Not mentioned | 93 (50.3) | 26 (14.1) | 0.68 (0.32 to 1.46) | 0.62 (0.23 to 1.64) |
| Private | 20 (10.8) | 7 (3.8) | 0.94 (0.31 to 2.85) | 0.86 (0.23 to 3.17) |
| Public | 17 (9.2) | 6 (3.2) | 0.95 (0.30 to 3.07) | 0.96 (0.24 to 3.76) |
| AMSTAR-2 rating | ||||
| High | 24 (13) | 7 (3.8) | 1 (Reference) | 1 (Reference) |
| Moderate | 110 (59.5) | 7 (3.8) | 1.13 (0.32 to 3.98) | 0.93 (0.23 to 3.87) |
| Low | 29 (15.7) | 12 (6.5) | 1.71 (0.54 to 5.41) | 1.68 (0.44 to 6.49) |
| Critically low | 110 (59.5) | 33 (17.8) | 1.04 (0.39 to 2.75) | 1.19 (0.38 to 3.77) |
| Journal impact factor*, M (SD) | 7.80 (11.52) | 6.90 (8.45) | 0.99 (0.96 to 1.02) | 1.01 (0.97 to 1.05) |
| Publication year (1991–2020) | 1.05 (1.00 to 1.11) | 1.09 (1.00 to 1.18) | ||
*18 journals did not have an impact factor.
AMSTAR, A MeaSurement Tool to Assess systematic Reviews; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.