Table 2.
Reporting of key methodological components of the systematic review process in network meta-analyses, by journal type
| Items | Overall (n=121) | General journals (n=55) | Specialty journals (n=66) |
|---|---|---|---|
| Introduction | |||
| Questions referring to participants, interventions, comparisons, outcomes, and study design | 110 (91) | 51 (93) | 59 (89) |
| Methods | |||
| Existence of systematic review protocol | 15 (12) | 9 (16) | 6 (9) |
| Primary outcome(s) | 85 (70) | 44 (80) | 41 (62) |
| Information sources searched | |||
| Databases searched | 118 (98) | 53 (96) | 65 (98) |
| Electronic search strategy for each database | 33 (27) | 19 (35) | 14 (21) |
| Date of last search for each database | 109 (90) | 50 (91) | 59 (89) |
| Period covered by search for each database | 83 (69) | 36 (65) | 47 (71) |
| Search for any other sources (conference abstracts, unpublished studies, textbooks, specialty registers, contact with study authors, reviewing the references in the studies found or any relevant systematic reviews) | 79 (65) | 38 (69) | 41 (62) |
| Reviewing the references in the studies found or any relevant systematic reviews | 54 (45) | 27 (49) | 27 (41) |
| Search for ongoing studies | 19 (16) | 13 (24) | 6 (9) |
| Restriction or no restriction related to language | 92 (76) | 42 (76) | 50 (76) |
| Restriction or no restriction related to the publication status | 82 (68) | 38 (69) | 44 (67) |
| Study selection and data collection process | |||
| Process for selecting studies | 79 (65) | 35 (64) | 44 (67) |
| Method of data extraction | 89 (74) | 42 (76) | 47 (71) |
| Methods used for assessing risk of bias of individual studies | 60 (50) | 27 (49) | 33 (50) |
| Methods to incorporate assessment of risk of bias of individual studies in the analysis or conclusions of review | |||
| Subgroup analysis | 9 (7) | 4 (7) | 5 (8) |
| Inclusion criteria | 4 (3) | 1 (2) | 3 (5) |
| GRADE | 4 (3) | 4 (7) | 0 (0) |
| Adjustment | 2 (2) | 2 (4) | 0 (0) |
| Any of these methods | 19 (16) | 11 (20) | 8 (13) |
| Assessment of risk of bias that may affect the cumulative evidence (publication bias) | 18 (15) | 11(20) | 7 (11) |
| Results | |||
| Study selection | |||
| No of studies screened, assessed for eligibility, and included in the review | 90 (74) | 43 (78) | 47 (71) |
| List of studies included | 117 (97) | 53 (96) | 64 (97) |
| List of studies excluded | 9 (7) | 6 (11) | 3 (5) |
| Study characteristics | |||
| Description of network | 82 (68) | 39 (71) | 43 (65) |
| Characteristics of patients (for example, age, female:male ratio) | 70 (58) | 30 (55) | 40 (61) |
| Duration of follow-up of patients | 60 (50) | 26 (47) | 34 (52) |
| Duration of interventions | 34 (28) | 15 (27) | 19 (29) |
| Description of interventions | 64 (53) | 30 (55) | 34 (52) |
| No of study groups | 95 (79) | 42 (76) | 53 (80) |
| No of patients | 97 (80) | 41 (75) | 56 (85) |
| Funding source | 13 (11) | 8 (15) | 5 (8) |
| Risk of bias within studies | 51 (42) | 23 (42) | 28 (42) |
| Risk of bias across studies (publication bias) | 18 (15) | 11 (20) | 7 (11) |
| Discussion | |||
| Reporting of limitations at review level (reporting or publication bias) | 58 (48) | 32 (58) | 26 (39) |
| Other items | |||
| Assumptions required in network meta-analysis | |||
| Homogeneity assumption | 107 (88) | 50 (91) | 57 (86) |
| Similarity assumption | 41 (34) | 18 (33) | 23 (35) |
| Consistency or exchangeability assumption | 58 (48) | 32 (58) | 26 (39) |
| Conflict of interest | 95 (79) | 47 (85) | 48 (73) |
Data are number (%) of reports featuring the corresponding item.