TABLE 2.
Methodological characteristics of systematic reviews1
| Reviews (n = 150) | |
|---|---|
| Did the review cite a reporting guideline?2 | |
| PRISMA | 83 (55.3) |
| MOOSE | 23 (15.3) |
| None | 45 (30.0) |
| Did the review cite a protocol? | |
| Yes | 30 (20.0) |
| No | 120 (80.0) |
| Among reviews with a protocol (n = 30; 20.0%), were there deviations from the methods described in the protocol? | |
| Yes, and deviations were explained | 2 (6.7) |
| Yes, but deviations were not explained | 13 (43.3) |
| The protocol was not publicly accessible | 5 (16.7) |
| No | 10 (33.3) |
| Eligible study designs2 | |
| Cohort | 146 (97.3) |
| Case-control | 97 (64.7) |
| Cross-sectional | 80 (53.3) |
| Randomized controlled trials | 74 (49.3) |
| Databases searched, n | 3 [2–3] |
| Databases searched2 | |
| MEDLINE/PubMed | 150 (100) |
| EMBASE | 98 (65.3) |
| Web of Science | 63 (42.0) |
| Cochrane CENTRAL | 52 (34.7) |
| Scopus | 45 (30.0) |
| Google Scholar | 17 (11.3) |
| CINAHL | 15 (10.0) |
| Other | 37 (24.7) |
| Did the review report a replicable search strategy? | |
| Yes, the search strategy is replicable | 108 (72.0) |
| No, but key terms are reported | 35 (23.3) |
| No | 7 (4.7) |
| Language restrictions? | |
| Yes | 75 (50.0) |
| No | 75 (50.0) |
| Did the review search for unpublished data (i.e., conference abstracts, dissertations, unpublished studies, partially published studies,expert solicitation)? | |
| Yes | 14 (9.3) |
| No | 136 (90.7) |
| Method for screening of studies for eligibility | |
| Completed in duplicate or more | 106 (70.7) |
| Completed by 1 reviewer | 4 (2.7) |
| Completed by 1 reviewer and a subset verified by a second reviewer | 3 (2.0) |
| Completed by 1 reviewer with uncertainties verified by a second reviewer | 1 (0.7) |
| Not reported | 36 (24.0) |
| Method for data extraction from primary studies | |
| Completed in duplicate | 88 (58.7) |
| Completed by 1 reviewer | 3 (2.0) |
| Completed by 1 reviewer and verified by a second reviewer | 10 (6.7) |
| Completed by 1 reviewer with uncertainties verified by a second reviewer | 1 (0.7) |
| Not reported | 48 (32.0) |
| Method for the assessment of risk of bias among reviews that assessed risk of bias (n = 131; 87.3%) | |
| Completed in duplicate or more | 69 (52.7) |
| Completed by 1 reviewer and verified by a second reviewer | 1 (0.7) |
| Not reported | 61 (46.7) |
| Method for the synthesis of results | |
| Meta-analysis | 115 (76.7) |
| Narrative | 21 (14.0) |
| Tabular/graphical summary of quantitative results | 14 (9.3) |
| Among reviews without meta-analysis (n = 35; 23.33%), was the decision to not perform meta-analysis explained in the review article? | |
| Yes | 14 (40.0) |
| No | 21 (60.0) |
1
Values are n (%) or median [IQR]. CENTRAL, Cochrane Central Register of Controlled Trials; CINAHL, Cumulative Index to Nursing and Allied Health Literature; MOOSE, Meta-analyses Of Observational Studies in Epidemiology; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
2
Each review can be classified in >1 category.