Table 1 Certainty of evidence according to the grading of recommendations assessment, development, and evaluation (GRADE) scale
Certainty assessment | № of patients | Effect | Certainty | Importance | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
№ of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | [Antibiotics] | [Placebo] | Relative (95% CI) | Absolute (95% CI) | ||
Total postoperative infectious complications | ||||||||||||
7 | Randomized trials | Seriousa | Not serious | Not serious | Not seriousb | None | 78/866 (9.0%) | 95/881 (10.8%) | RR 0.84 (0.63 to 1.12) | 17 fewer per 1000 (from 40 fewer to 13 more) | ⨁⨁⨁◯ Moderate | CRITICAL |
Total surgical site infections | ||||||||||||
6 | Randomized trials | Seriousa | Not serious | Not serious | Not seriousb | None | 2/651 (0.3%) | 8/655 (1.2%) | RR 0.79 (0.56 to 1.12) | 3 fewer per 1000 (from 5 fewer to 1 more) | ⨁⨁⨁◯ Moderate | CRITICAL |
Total distant infections | ||||||||||||
5 | Randomized trials | Seriousa | Not serious | Not serious | Not seriousb | None | 21/820 (2.6%) | 20/837 (2.4%) | RR 1.01 (0.55 to 1.88) | 0 fewer per 1000 (from 11 fewer to 21 more) | ⨁⨁⨁◯ Moderate | CRITICAL |
Total postoperative non-infectious complications | ||||||||||||
6 | Randomized trials | Seriousa | Not serious | Not serious | Not seriousb | None | 78/824 (9.5%) | 94/833 (11.3%) | RR 0.84 (0.64 to 1.11) | 18 fewer per 1000 (from 41 fewer to 12 more) | ⨁⨁⨁◯ Moderate | IMPORTANT |
Mortality | ||||||||||||
5 | Randomized trials | Seriousa | Not serious | Not serious | Very seriousd | None | 0/699 (0.0%) | 2/711 (0.3%) | RR 0.34 (0.04 to 3.23) | 2 fewer per 1000 (from 3 fewer to 6 more) | ⨁◯◯◯ Very low | CRITICAL |
Readmission | ||||||||||||
5 | Randomized trials | Seriousa | Not serious | Not serious | Seriousc | None | 28/731 (3.8%) | 41/742 (5.5%) | RR 0.69 (0.43 to 1.11) | 17 fewer per 1000 (from 31 fewer to 6 more) | ⨁⨁◯◯ Low | IMPORTANT |
Length of hospital stay | ||||||||||||
5 | Randomized trials | Seriousa | Seriouse | Not serious | Not serious | None | 617 | 626 | - | MD 0.89 Day higher (0.14 lower to 1.92 higher) | ⨁⨁◯◯ Low | IMPORTANT |