Table 1.
The GRADE framework for the major outcomes.
| Question: should vitamin E versus Control be used for NAFLD? | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Certainty assessment | № of patients | Effect | Certainty | Importance | ||||||||||
| № of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | Vitamin E | Control | Relative (95% CI) |
Absolute (95% CI) |
||||
| ALT (follow up: 24 months; scale from: −17.493 to −5.367) | ||||||||||||||
| 11 | Randomized trials | Not serious | Seriousa | Not serious | Seriousb | Very strong association dose response gradient | 382 | 572 | – | MD 11.43 1000 lower
(17.493 lower to 5.367 lower) |
⨁⨁⨁⨁ HIGH |
IMPORTANT | ||
| AST (follow up: 24 months; scale from: −11.686 to −1.846) | ||||||||||||||
| 10 | Randomized trials | Not serious | Seriousa | Not serious | Seriousb | Strong association dose response gradient |
350 | 576 | – | MD 6.766 1000 lower
(11.686 lower to 1.846 lower) |
⨁⨁⨁⨁ HIGH |
IMPORTANT | ||
| Fibrosis (follow up: 24 months; scale from: −0.426 to −0.023) | ||||||||||||||
| 7 | Randomized trials | Not serious | Not serious | Not serious | Seriousb | Strong association | 261 | 428 | – | MD 0.224 1000 lower
(0.426 lower to 0.023 lower) |
⨁⨁⨁⨁ HIGH |
CRITICAL | ||
| NAS (follow up: 24 months; scale from: −2.495 to −0.510) | ||||||||||||||
| 7 | Randomized trials | Not serious | Not serious | Not serious | Seriousb | Strong association | 256 | 446 | – | MD 1.503 1000 lower
(2.495 lower to 0.51 lower) |
⨁⨁⨁⨁ HIGH |
CRITICAL | ||
a
Eight included studies reported superiority of vitamin E alone or combined compared with control. Five other trials demonstrated that the control was more efficient in reducing NAFLD relative to Vitamin E. Another two trials reported that the two arms did not differ markedly in terms of their effects in improving hepatic and metabolic outcomes.
b
Wide 95% CI was present at some endpoints.
ALT, alanine aminotransferase; AST, aspartate aminotransferase; CI, confidence interval; GRADE, grading of recommendations assessment development and evaluation; MD, mean difference; NAFLD, non-alcoholic fatty liver disease; NAS, NAFLD activity score.