Table 3 Meta-analysis methods of therapeutic meta-analyses published in 2013 and including non-randomized studies (n = 188)
From: Meta-analyses including non-randomized studies of therapeutic interventions: a methodological review
Characteristic | Included NRSI only | Included NRSI&RCTs | All meta-analyses |
|---|---|---|---|
(n = 69) | (n = 119) | (n = 188) | |
No (%) | No (%) | No (%) | |
Studies combined | |||
Type of studies included | |||
Only prospective cohort studies | 2 (3) | 3 (3) | 5 (3) |
Only cohort studies | 18 (26) | 34 (29) | 52 (28) |
Including also case–control studies | 18 (26) | 28 (23) | 46 (24) |
Including all types of NRSI | 5 (7) | 18 (15) | 23 (12) |
Other | 28 (41) | 39 (33) | 67 (36) |
“Observational studies” | 6 (9) | 22 (18) | 28 (15) |
“Prospective and retrospective studies” | 11 (16) | 12 (10) | 23 (12) |
“Retrospective studies” | 11 (16) | 5 (4) | 16 (9) |
Did not clearly report design for each study | 43 (62) | 87 (73) | 130 (69) |
Meta-analysis combining results of NRSI and RCTs | NA | 88 (74) | NA |
Results also presented separately | NA | 44/88 (50) | NA |
Meta-analysis combining studies of different designs | 39 (57) | 61 (51) | 100 (53) |
Meta-analysis model | |||
Network meta-analysis | 0 | 2 (2) | 2 (1) |
Crude or adjusted estimates used | |||
Combined crude and adjusted estimates | 10 (14) | 12 (10) | 22 (12) |
Adjusted | 8 (12) | 13 (11) | 21 (11) |
Both crude and adjusted estimates separately | 4 (6) | 4 (3) | 8 (4) |
Crude | 2 (3) | 4 (3) | 6 (3) |
Not reported/unclear | 45 (65) | 86 (72) | 131 (70) |
If adjusted, list of confounding factors | 15/22 (68) | 19/29 (66) | 34/51 (67) |
Type of model | |||
Random-effects model | 39 (57) | 56 (47) | 95 (50) |
Fixed-effects model, unless high heterogeneity, then random-effects model | 19 (28) | 33 (28) | 52 (28) |
Both fixed- and random-effects models | 5 (7) | 21 (18) | 26 (14) |
Fixed-effects model | 3 (4) | 6 (5) | 9 (5) |
Not reported/unclear | 3 (4) | 3 (3) | 6 (3) |
Heterogeneity assessment & exploration | |||
Heterogeneity assesseda | 66 (96) | 116 (97) | 182 (97) |
I2 | 57 (83) | 107 (90) | 164 (87) |
Cochran Q χ2 test | 41 (59) | 74 (62) | 115 (61) |
τ2 | 4 (6) | 2 (2) | 6 (3) |
Heterogeneity exploreda | 54 (82) | 103 (87) | 157 (84) |
Meta-regression analysis | 13 (19) | 21 (18) | 34 (18) |
Subgroup analysis | 44 (64) | 82 (69) | 126 (67) |
Sensitivity analysis | 35 (51) | 74 (62) | 109 (58) |
Reporting bias assessmenta | 49 (71) | 78 (66) | 127 (68) |
Standard funnel plot | 41 (59) | 70 (59) | 111 (59) |
Egger’s test | 32 (46) | 36 (30) | 68 (36) |
Begg’s test | 18 (26) | 24 (20) | 42 (22) |
Among MAs with ≥10 studies, reporting bias assessed | 24/29 (83) | 58/76 (76) | 82/105 (78) |