Table 1 Evidence profile
Certainty assessment | No. of patients | Effect | Certainty | Importance | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
No. of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | Vitamin C | Placebo | Relative (95% CI) | Absolute (95% CI) | ||
Long term mortality (more than 60 days) | ||||||||||||
6 | Randomized trials | Seriousa | Not serious | Not serious | Not serious | None | 607/1440 (42.2%) | 545/1441 (37.8%) | RR 1.11 (1.02 to 1.22) | 42 more per 1000 (from 8 to 83 more) | ⨁⨁⨁◯ Moderate | Critical |
28 or 30 days mortality | ||||||||||||
15 | Randomized trials | Very seriousb | Seriousc | Not serious | Not serious | None | 573/1940 (29.5%) | 584/1916 (30.5%) | RR 0.89 (0.77–1.04) | 34 fewer per 1000 (from 70 fewer to 12 more) | ⨁◯◯◯ Very low | CRITICAL |
In-hospital mortality | ||||||||||||
12 | Randomized trials | Very seriousb | Seriousd | Not serious | Not serious | None | 383/1194 (32.1%) | 382/1150 (33.2%) | RR 0.94 (0.76 to 1.16) | 20 fewer per 1000 (from 80 fewer to 53 more) | ⨁◯◯◯ Very low | Critical |
Length of ICU stay (days) | ||||||||||||
16 | Randomized trials | Very seriousb | Very seriouse | Not serious | Not serious | None | 1785 | 1749 | – | MD 0.25 lower (0.72 lower to 0.22 higher) | ⨁◯◯◯ Very low | Critical |
Length of hospital stay (days) | ||||||||||||
12 | Randomized trials | Very seriousb | Very seriousf | Not serious | Not serious | None | 1722 | 1685 | – | MD 0.24 higher (0.97 lower to 1.45 higher) | ⨁◯◯◯ Very low | Critical |
Acute kidney injury | ||||||||||||
9 | Randomized trials | Very seriousb | Not serious | Not serious | Not serious | None | 338/1113 (30.4%) | 324/1117 (29.0%) | RR 1.02 (0.93–1.13) | 6 more per 1000 (from 20 fewer to 38 more) | ⨁⨁◯◯ Low | Critical |