Table 3.
Reported methodological quality of included surgical randomized trials
| 1999 (n = 300) | 2009 (n = 450) | RR*† | P†^ | 2019 (n = 438) | RR* | P~ | |
|---|---|---|---|---|---|---|---|
| Primary outcome stated explicitly | 203 (67.7) | 297 (66.0) | 0.98 (0.88, 1.08) | 0.693 | 315 (71.9) | 0.92 (0.84, 1.00) | 0.057 |
| Sample size calculation described | 101 (33.7) | 218 (48.4) | 1.44 (1.20, 1.73) | <0.001 | 296 (61.4) | 0.72 (0.64, 0.80) | <0.001 |
| Baseline present | 272 (90.7) | 414 (92.0) | 1.02 (0.97, 1.06) | 0.594 | 412 (94.1) | 0.98 (0.94, 1.01) | 0.228 |
| Generation of allocation: reported and adequate | 96 (32.0) | 213 (47.3) | 1.48 (1.22, 1.79) | <0.001 | 283 (64.6) | 1.49 (1.28, 1.74) | <0.001 |
| Computer | 52 (17.3) | 138 (30.7) | 212 (48.4) | ||||
| Random table | 24 (8.0) | 30 (6.7) | 41 (9.4) | ||||
| Other adequate | 20 (6.7) | 45 (10.0) | 30 (6.8) | ||||
| Concealment of allocation: reported and adequate | 96 (32.0) | 224 (50.0) | 1.56 (1.29, 1.88) | <0.001 | 287 (65.5) | 0.76 (0.68, 0.85) | <0.001 |
| Central/pharmacy | 32 (10.7) | 60 (13.3) | 88 (20.1) | ||||
| Envelopes | 57 (19.0) | 145 (32.2) | 140 (32.0) | ||||
| Other adequate | 7 (2.3) | 19 (4.2) | 59 (13.5) | ||||
| Blinding: any type of blinding | 103 (34.3) | 138 (30.7) | 0.89 (0.73, 1.10) | 0.300 | 181 (41.3) | 0.74 (0.62, 0.89) | 0.001 |
| Double blinding stated | 72 (24.0) | 90 (20.0) | 0.83 (0.63, 1.10) | 0.205 | 71 (16.2) | 0.81 (0.61, 1.07) | 0.143 |
| Type of analyses | |||||||
| Intention to treat | 60 (20.0) | 149 (33.1) | 1.66 (1.27, 2.15) | <0.001 | 156 (35.6) | 1.08 (0.90, 1.29) | 0.432 |
| Per protocol | 9 (3.0) | 16 (3.6) | 14 (3.2) | ||||
| Not stated | 231 (77.0) | 285 (63.3) | 268 (61.2) | ||||
| Handling of drop-outs adequate | 253 (84.3) | 373 (82.9) | 1.01 (0.95, 1.07) | 0.836 | 282 (64.4) | 0.78 (0.72, 0.84) | <0.001 |
| Low risk of bias | 17 (5.7) | 66 (14.7) | 2.59 (1.55, 4.32) | <0.001 | 97 (22.1) | 1.51 (1.14, 2.01) | 0.004 |
Values are n (%) unless indicated otherwise; *values in parentheses are 95% confidence intervals. †This comparison was performed in the authors’ previous study8. ^Comparing 1999 and 2009 using Fisher’s exact, χ2, and Mann–Whitney U tests. ~Comparing 2009 and 2019 using Fisher’s exact, χ2, and Mann–Whitney U tests. RR, relative rate.