Table 1.
Baseline characteristics of the included Cochrane reviews and high-impact journal SRs
| Cochrane | High-impact journals | |||||||||
| Cochrane reviews (n=346) | Total high-impact journal SRs (n=215) | J Natl Cancer Inst (n=56) |
J Clin Oncol
(n=56) |
Lancet Oncology
(n=53) |
The BMJ
(n=22) |
Lancet
(n=14) |
JAMA
(n=12) |
CA Cancer J Clin
(n=1) |
Cancer Research
(n=1) |
|
| Year first published (number of SR (%)) | ||||||||||
| 2011 | 45 (13.1) | 45 (20.9) | 9 (16.1) | 14 (25) | 13 (24.5) | 2 (9.1) | 4 (28.6) | 3 (25) | ||
| 2012 | 60 (17.3) | 50 (23.2) | 20 (35.7) | 11 (19.6) | 11 (20.8) | 4 (18.2) | 1 (7.1) | 3 (25) | ||
| 2013 | 80 (23.1) | 31 (14.4) | 7 (12.5) | 8 (14.3) | 8 (15.1) | 5 (22.7) | 2 (14.3) | 1 (8.3) | ||
| 2014 | 59 (17.1) | 51 (23.7) | 11 (19.6) | 10 (17.9) | 15 (28.3) | 7 (31.8) | 4 (28.6) | 4 (33.3) | ||
| 2015 | 69 (19.9) | 32 (14.9) | 6) (10.7) | 11 (19.6) | 5 (9.4) | 4 (18.2) | 3 (21.4) | 1 (8.3) | 1 (100) | 1 (100) |
| 2016 | 33 (9.5) | 6 (2.8) | 3 (5.4) | 2 (3.6) | 1 (1.9) | |||||
| Region (number of SR (%)) | ||||||||||
| Europe | 233 (67.3) | 95 (44.2) | 14 (25) | 20 (35.7) | 34 (64.2) | 12 (54.5) | 13 (92.9) | 1 (8.3) | 1 (100) | |
| North America | 26 (7.5) | 88 (40.9) | 33 (58.9) | 27 (48.2) | 10 (18.9) | 6 (27.3) | 1 (7.1) | 10 (83.3) | 1 (100) | |
| Asia | 49 (14.2) | 16 (7.4) | 6 (10.7) | 3 (5.4) | 3 (5.7) | 3 (13.6) | 1 (8.3) | |||
| Australia/New Zealand | 19 (5.5) | 14 (6.5) | 2 (3.6) | 6 (10.7) | 6 (11.3) | |||||
| South America | 13 (3.8) | 1 (0.5) | 1 (1.8) | |||||||
| Africa | 6 (1.7) | 1 (0.5) | 1 (4.5) | |||||||
| Review type (number of SR (%)) | ||||||||||
| Study-level data | 331 (95.7) | 147 (68.4) | 39 (69.6) | 40 (71.4) | 35 (66) | 19 (86.4) | 1 (7.1) | 11 (91.7) | 1 (100) | 1 (100) |
| IPD | 3 (0.9) | 67 (31.2) | 17 (30.4) | 15 (26.8) | 18 (34) | 3 (13.6) | 13 (92.9) | 1 (8.3) | ||
| Both | 12 (3.5) | 1 (0.5) | 1 (1.8) | |||||||
| Network meta-analysis (number of SR (%)) | 2 (0.6) | 6 (2.8) | 3 (5.4) | 3 (5.7) | ||||||
| Study type (number of SR (%)) | ||||||||||
| RCT | 264 (76.3) | 75 (34.9) | 15 (26.8) | 21 (37.5) | 14 (26.4) | 7 (31.8) | 12 (85.7) | 5 (41.7) | 1 (100) | |
| non-RCT | 5 (1.4) | 85 (39.5) | 27 (48.2) | 16 (28.6) | 27 (50.9) | 12 (54.5) | 1 (7.1) | 2 (16.7) | ||
| Both | 77 (22.3) | 46 (21.4) | 9 (16.1) | 19 (33.9) | 9 (17) | 3 (13.6) | 1 (7.1) | 5 (41.7) | ||
| Unclear | 9 (4.2) | 5 (8.9) | 3 (5.7) | 1 (100) | ||||||
| Population (number of SR (%)) | ||||||||||
| Adult | 318 (9.9) | 151 (70.2) | 39 (69.6) | 43 (76.8) | 32 (60.4) | 14 (63.6) | 13 (92.9) | 9 (75) | 1 (100) | |
| Paediatric | 26 (7.5) | 6 (2.8) | 1 (1.8) | 1 (1.8) | 4 (7.5) | |||||
| Both | 2 (0.6) | 22 (10.2) | 5 (8.9) | 6 (10.7) | 7 (13.2) | 4 (18.2) | ||||
| Unclear | 36 (16.7) | 11 (19.6) | 6 (10.7) | 10 (18.9) | 4 (18.2) | 1 (7.1) | 3 (25) | 1 (100) | ||
| Included studies (median (IQR)) | 6 (2-13) |
18 (10-38,8) |
20 (12–43.8) |
16 (9–36.3) |
24 (12.8–44.8) |
16 (9.6–26.5) |
16 (25–9.8) |
16.5 (10.3–24.8) |
14 | 37 |
| Included patients (median (IQR)) | 1020 (194.5–2845) |
7730 (3288–29423) |
8216 (3288–35568) |
4758.5 (184.5–11 091.8) |
4600 (3033–21137) |
1 17 597 (10 903–890992.3) |
21 471.5 (13 287.5–45 195.8) |
12 813.5 (4075.5–48 067.3) |
3377 | Not reported |
| Citations (median (IQR)) | 3 (1-7) |
46 (18.5–86.5) |
30.5 (9.8–55.3) |
48.5 (18–70.3) |
40 (22-97) |
40 (15–80.3) |
157 (54–351.8) |
101 (45.3–155.8) |
8 | 15 |
CA Cancer J Clin, A Cancer Journal for Clinicians; Cancer Res, Cancer Research; IPD, individual patient data; J Clin Oncol, Journal of Clinical Oncology; J Natl Cancer Inst, Journal of the National Cancer Institute; RCT, randomised controlled trial; SR, systematic review.