Characteristics of the overall sample
Tables
1,
2 and
3 show the SR, included primary studies, and methodological characteristics of the sample, overall and by type of review question. The SRs originated almost exclusively from high (
n = 1247, 78.0%) and upper-middle (
n = 317, 19.8%) income countries. The USA (
n = 384, 24.0%), China (
n = 201, 12.6%), the UK (n = 201, 12.6%), Canada (
n = 150, 9.4%), and Australia (
n = 136, 8.5%) were the top child-relevant SR-producing countries.
Table 1
Characteristics of non-Cochrane child-relevant systematic reviews published in 2014, overall and by type of review question
Total number of systematic reviews (%) | 1598 (100.0) | 753 (47.1) | 701 (43.8) | 91 (5.7) | 53 (3.3) |
Corresponding author: continent, n (%) |
Asia | 299 (18.7) | 123 (16.3) | 148 (21.1) | 25 (27.5) | 3 (5.7) |
Africa | 24 (1.5) | 11 (1.5) | 11 (1.6) | 1 (1.1) | 1 (1.9) |
North America | 534 (33.4) | 287 (38.1) | 199 (28.4) | 30 (33.0) | 18 (34.0) |
South America | 65 (4.1) | 25 (3.3) | 37 (5.3) | 2 (2.2) | 1 (1.9) |
Europe | 535 (33.5) | 255 (33.9) | 232 (33.1) | 26 (28.6) | 22 (41.5) |
Oceania | 141 (8.8) | 52 (6.9) | 74 (10.6) | 7 (7.7) | 8 (15.1) |
Corresponding author: country income level (World Bank), n (%) |
High | 1247 (78.0) | 610 (81.0) | 524 (74.8) | 64 (70.3) | 49 (92.5) |
Upper middle | 317 (19.8) | 126 (16.7) | 163 (23.3) | 25 (27.5) | 3 (5.7) |
Lower middle | 27 (1.7) | 15 (2.0) | 9 (1.3) | 2 (2.2) | 1 (1.9) |
Low | 7 (0.4) | 2 (0.3) | 5 (0.7) | 0 (0.0) | 0 (0.0) |
Journal type, n (%) |
General medical | 73 (4.6) | 28 (3.7) | 43 (6.1) | 1 (1.1) | 1 (1.9) |
Specialty medical | 1137 (71.2) | 535 (71.0) | 503 (71.8) | 67 (73.6) | 32 (60.4) |
General pediatric | 110 (6.9) | 63 (8.4) | 35 (5.0) | 8 (8.8) | 4 (7.5) |
Specialty pediatric | 173 (10.8) | 87 (11.6) | 68 (9.7) | 6 (6.6) | 12 (22.6) |
Otherb | 105 (6.6) | 40 (5.3) | 52 (7.4) | 9 (9.9) | 4 (7.5) |
Sources of fundingc, n (%) |
Academic | 228 (14.3) | 96 (12.7) | 118 (16.8) | 9 (9.9) | 5 (9.4) |
Government | 557 (34.9) | 239 (31.7) | 265 (37.7) | 37 (40.7) | 16 (30.2) |
Industry | 53 (3.3) | 23 (3.1) | 22 (3.1) | 5 (5.5) | 3 (5.7) |
Private (foundation) | 193 (12.1) | 81 (10.8) | 97 (13.8) | 8 (8.8) | 7 (13.2) |
Other | 32 (2.0) | 13 (1.7) | 14 (2.0) | 3 (3.3) | 2 (3.8) |
No funding | 248 (15.5) | 130 (17.3) | 100 (14.2) | 11 (12.1) | 7 (13.2) |
Not reported | 543 (34.0) | 281 (37.3) | 215 (30.7) | 29 (31.9) | 18 (34.0) |
Review is an update, n (%) | 32 (2.0) | 18 (2.4) | 11 (1.6) | 2 (2.2) | 1 (1.9) |
Existing a-priori protocol for the reviewd, n (%) |
Yes (reported) | 246 (15.4) | 130 (17.3) | 90 (12.8) | 16 (17.6) | 10 (18.9) |
No (reported) | 16 (1.0) | 7 (0.9) | 8 (1.1) | 1 (1.1) | 0 (0.0) |
Not mentioned | 1336 (83.6) | 616 (81.8) | 603 (86.0) | 74 (81.3) | 43 (81.1) |
Registration of the reviewd, n (%) |
Yes (reported) | 111 (6.9) | 59 (7.8) | 35 (5.0) | 9 (9.9) | 8 (15.1) |
No (reported) | 24 (1.5) | 9 (1.2) | 12 (1.7) | 3 (3.3) | 0 (0.0) |
Not mentioned | 1463 (91.6) | 685 (91.0) | 654 (93.3) | 79 (86.8) | 45 (84.9) |
Table 2
Included study characteristics for non-Cochrane child-relevant systematic reviews published in 2014, overall and by type of review question
Study designs: eligible, n (%) |
Only RCTs | 203 (12.7) | 202 (26.8) | 1 (0.1) | 0 (0.0) | 0 (0.0) |
RCTs and other designs | 765 (47.9) | 476 (63.2) | 240 (34.2) | 31 (34.1) | 18 (34.0) |
Only non-RCTs | 472 (29.5) | 49 (6.5) | 346 (49.4) | 48 (52.7) | 29 (54.7) |
Unclear or not reported | 158 (9.9) | 26 (3.5) | 114 (16.3) | 12 (13.2) | 6 (11.3) |
Study designs: included in the review, n (%) |
Only RCTs | 231 (14.5) | 227 (30.1) | 1 (0.1) | 0 (0.0) | 0 (0.0) |
RCTs and other designs | 420 (26.3) | 334 (44.4) | 66 (9.4) | 13 (14.3) | 7 (13.2) |
Only non-RCTs | 796 (49.8) | 169 (22.4) | 523 (74.6) | 71 (78.0) | 36 (67.9) |
Not applicable (empty) | 4 (0.3) | 4 (0.5) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
Unclear or not reported | 147 (9.2) | 19 (2.5) | 111 (15.8) | 7 (7.7) | 10 (18.9) |
Included studies, median (IQR) | 19 (11, 33) | 15 (9, 26) | 23 (13, 40) | 18 (12, 28) | 20 (12, 41) |
Reported on the number of participants, n (%)b | 692 (43.4) | 370 (49.4) | 273 (38.9) | 41 (45.1) | 8 (15.1) |
Included participants, median (IQR) | 2134 (648, 13,079) | 1042 (427, 3324) | 11,038 (2098, 63,897) | 1086 (515, 2831) | 2036 (1284, 5374) |
Participant type |
Children only | 628 (39.3) | 353 (46.9) | 212 (30.2) | 41 (45.1) | 25 (47.2) |
Children and adults | 787 (49.2) | 335 (44.5) | 384 (54.8) | 46 (50.5) | 27 (50.9) |
Pregnancy | 176 (11.0) | 65 (8.6) | 99 (14.1) | 4 (4.4) | 0 (0.0) |
Adults onlyc | 7 (0.4) | 0 (0.0) | 6 (0.9) | 0 (0.0) | 1 (1.9) |
Table 3
Methodological characteristics for non-Cochrane child-relevant systematic reviews published in 2014, overall and by type of review question
Objective stated, n (%) | 1587 (99.3) | 750 (99.6) | 694 (99.0) | 90 (98.9) | 53 (100.0) |
Primary outcome(s) specified, n (%) | 374 (23.4) | 281 (37.3) | 74 (10.6) | 17 (18.7) | 2 (3.8) |
When not stated, outcomes of interest can be inferred, n (%) | 1099 (89.8) | 405 (85.8) | 580 (92.5) | 65 (87.8) | 49 (96.1) |
Quality of included studies assessedb, n (%) | 953 (59.6) | 532 (70.7) | 325 (46.4) | 63 (69.2) | 33 (62.3) |
Certainty of the body of evidence assessed using GRADEb, n (%) |
Yes | 72 (4.5) | 58 (7.7) | 12 (1.7) | 2 (2.2) | 0 (0.0) |
Used another method | 30 (1.9) | 17 (2.3) | 8 (1.1) | 1 (1.1) | 4 (7.5) |
No | 1492 (93.4) | 674 (89.5) | 681 (97.1) | 88 (96.7) | 49 (92.5) |
Evidence synthesis method, n (%) |
Narrative only | 741 (46.4) | 352 (46.7) | 307 (43.8) | 36 (39.6) | 46 (86.8) |
Statistical | 857 (53.6) | 401 (53.3) | 394 (56.2) | 55 (60.4) | 7 (13.2) |
When synthesized statistically, analysis method used, n (%) |
Meta-analysis | 827 (96.5) | 384 (95.8) | 387 (98.2) | 50 (90.9) | 6 (85.7) |
Network meta-analysis | 5 (0.6) | 5 (1.2) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
Individual patient data meta- analysis | 12 (1.4) | 8 (2.0) | 0 (0.0) | 4 (7.3) | 0 (0.0) |
Otherc | 13 (1.5) | 4 (1.0) | 7 (1.8) | 1 (1.8) | 1 (14.3) |
The SRs spanned 47 of the 53 CRGs and the 8 most populated review groups contained 53.2% (n = 849) of the SRs: Developmental, Psychosocial and Learning Problems (n = 216, 13.5%); Metabolic and Endocrine Disorders (n = 132, 8.3%); Pregnancy and Childbirth (n = 124, 7.8%); Common Mental Disorders (n = 110, 6.9%); Airways (n = 70, 4.4%); Anaesthesia, Critical and Emergency Care (n = 69, 4.3%); Public Health (n = 67, 4.2%); and Infectious Diseases (n = 61, 3.8%). Some notable CRGs containing very few SRs were Skin (n = 15, 0.9%), Tobacco Addiction (n = 15, 0.9%), Back and Neck (n = 14, 0.9%), Neonatal (n = 14, 0.9%; neonatal reviews of RCTs only), Eyes and Vision (n = 12, 0.8%), Haematological Malignancies (n = 9, 0.6%), Neuromuscular (n = 7, 0.4%), and Urology (n = 3, 0.2%).
Most often, the SRs synthesized therapeutic (n = 753, 47.1%) or epidemiologic (n = 701, 43.8%) evidence. Although 39.3% (n = 628) of the SRs included evidence specific to children only, fewer were published in pediatric-specific journals (n = 283, 17.7%). Approximately half of SRs (n = 807, 50.5%) declared at least one external source of support; 15.5% (n = 248) had no external funding. The most common sources of support were governments (n = 557, 34.9%), academic or research institutes (n = 228, 14.3%), and foundations (n = 193, 12.1%).
Only three SRs (< 0.01%) included all of the methodological and reporting characteristics that we assessed. Few mentioned a published or registered protocol (n = 246, 15.4%) or SR registration (n = 111, 6.9%). One-third neglected to mention sources of support (n = 543, 34.0%) and more than half did not indicate the total number of included human participants (n = 902, 56.6%). Most (n = 1224, 76.6%) did not specify one or more primary outcome(s). In 9.9% (n = 158) of cases, eligible primary study designs were not mentioned, and in 9.2% (n = 147) the type(s) included in the SR was not discernable. Few SRs were identified as updates (n = 32, 2.0%). Some were labelled as updates by their authors, but appeared to be new.
Authors rarely searched only for RCTs (n = 203, 12.7%). Most commonly, both RCTs and other primary study designs were eligible (n = 765, 47.9%). This was reflected in the included primary studies, where most SRs relied solely on evidence from non-RCTs (n = 796, 49.8%) or a mix of designs (n = 420, 26.3%). Less than two-thirds of SRs (n = 953, 59.6%) included an assessment of the quality of the included studies and very few assessed the certainty of the body of evidence (n = 102, 6.4%; using Grading of Recommendations Assessment, Development and Evaluation (GRADE) (n = 72, 4.5%) or another method (n = 30, 1.9%)). The synthesis method used in SRs was roughly equally split between narrative (n = 741, 46.4%) and statistical (n = 857, 53.6%). There were 5 network meta-analyses and 12 individual patient data meta-analyses.
Characteristics of the sample by type of review question
Epidemiological SRs included the largest number of primary studies (median (IQR), 23 (13 to 40)) and human participants (11,038 (2098 to 63,897)). Compared to the overall sample, a larger proportion of diagnostic/prognostic SRs were published in Asia (n = 25/91, 27.5%), and therapeutic SRs in North America (n = 287/753, 38.1%). The Injuries CRG was the most strongly represented group among diagnostic/prognostic SRs, while the Developmental, Psychosocial, and Learning Problems CRG was predominant across all other review types.
Compared to the overall sample, epidemiological SRs more often included mixed samples of children and adults (n = 384/701, 54.8%) and less often included only children (n = 212/701, 30.2%), but the type of journal in which they were published did not differ. In contrast, the ‘other’ SRs were more often published in pediatric journals (n = 16/53, 30.1%), though the sample of these was small. The highest proportion of unfunded SRs was in the therapeutic group (n = 130/753, 17.3%). Industry funding was most common among the diagnostic/prognostic (n = 5/91, 5.5%) and ‘other’ (n = 3/53, 5.7%) SRs.
Reporting of the items of interest that we collected was most complete for the therapeutic SRs and least for the epidemiological and ‘other’ SRs. The therapeutic SRs most often indicated the type of primary studies sought (n = 727/753, 96.5%) and included (n = 734/753, 97.5%), reported the total number of human participants (n = 370/753, 49.4%), and identified a primary outcome (n = 281/753, 37.3%). The epidemiological SRs least often identified a published or registered SR protocol (n = 90/701, 12.8%) or registration in a SR registry (n = 35/701, 5.0%), and most often failed to indicate the type of primary studies sought (n = 114/701, 16.3%) and included (n = 111/701, 15.8%). The total number of participants (n = 273/701, 38.9%) and primary outcome (n = 74/701, 10.6%) were relatively infrequently reported among epidemiologic SRs, though the ‘other’ SRs also performed poorly in this respect.
All but one of the SRs seeking to include only RCTs was therapeutic; the epidemiologic, diagnostic/prognostic, and ‘other’ SRs more commonly sought only non-RCTs (49.4%, 52.7%, 54.7%, respectively). Non-RCTs were eligible for inclusion among 69.7% (n = 525/753) of the therapeutic SRs. The quality of the included studies was least frequently assessed in the epidemiologic SRs (n = 325/701, 46.4%), and most frequently in therapeutic (n = 532/753, 70.7%) and diagnostic/prognostic (n = 63/91, 69.2%) SRs. Certainty of the body of evidence was most often assessed in therapeutic SRs (n = 75/753, 10.0%), and rarely in epidemiologic (n = 20/701, 2.8%) or diagnostic/prognostic (n = 3/91, 3.3%) SRs.