for the main comparison.
| Vitamin A compared with placebo or no vitamin A for prevention of blindness | ||||||
|
Patient or population: children with measles infection and no clinically demonstrable vitamin A deficiency Settings: resource‐limited countries Intervention: vitamin A Comparison: placebo or no vitamin A | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo | Vitamin A | |||||
| Blindness | See comment | Not estimable | 260 (2 studies) | See comment | None of the studies reported blindness as an end point | |
|
Serum retinol (1 week post‐intervention) (mean X (µg/dL) ± standard error (SE) |
X ± SE in the placebo group was 29.0 ± 2.2 (95% CI 24.8 to 33.3) | X ± SE in the intervention group was 38.5 ±3.0 (95% CI 32.6 to 44.4) | 9.5 higher (2.2 higher to 16.7 higher) | 17 (1 study) | ⊕⊕⊕⊝ moderate | |
| Serum retinol (2 weeks post‐intervention) (mean X (µg/dL) ± standard error SE) | X ± SE in the placebo group was 19.0 ± 0.7 (95% CI 17.6 to 20.3) | X ± SE in the intervention group was 21.6 ± 1.1 (95% CI 19.5 to 23.7) | 2.7 higher (0.3 lower to 5.6 higher) | 155 (1 study) | ⊕⊕⊕⊝ moderate | |
| Serum retinol (6 weeks post‐intervention) (mean X (µg/dL) ± standard error SE) | X ± SE in the placebo group was 28.5 ± 2.4 (95% CI 23.86 to 33.12) | X ± SE in the intervention group was 31.1 ± 3.2 (95% CI 24.7 to 37.4) | 2.6 higher (5.3 lower to 10.4 higher) | 39 (1 study) | ⊕⊕⊕⊝ moderate | |
| Serum retinol (mean change 1 week post‐intervention) (mean X (µg/dL) ± standard error SE) | X ± SE in the placebo group was 17.3 ± 1.9 (95% CI 13.7 to 21.0) | X ± SE in the placebo group was 26.0 ± 3.3 (95% CI 19.6 to 32.4) | 8.6 higher (1.2 higher to 16.0 higher) | 17 (1 study) | ⊕⊕⊕⊝ moderate | |
| Weight gain 6 weeks post‐intervention (mean X (kg) ± standard error SE) | X ± SE in the placebo group was 0.9 ± 0.1 (95% CI 0.6 to 1.2) | X ± SE in the intervention group was 1.3 ± 0.2 (95% CI 1.3 to 1.3) | 0.4 higher (0.04 lower to 0.8 higher) | 48 (1 study) | ⊕⊕⊕⊝ moderate | |
| Weight gain 6 months post‐intervention (mean X (kg) ± standard error SE) | X ± SE in the placebo group was 2.4 ± 0.2 (95% CI 2.0 to 2.8) | X ± SE in the intervention group was 2.9 ± 0.2 (95% CI 2.4 to 3.3) | 0.5 higher (0.1 lower to 1.1 higher) | 36 (1 study) | ⊕⊕⊕⊝ moderate | |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; SE: standard error; GRADE: GRADE Working Group grades of evidence (see explanations) | ||||||
Assumed risk and corresponding risk in the table are from a single study in each case, and are not the usual combined mean or median risks across multiple studies.
GRADE Working Group grades of evidence High quality (⊕⊕⊕⊕): Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality (⊕⊕⊕⊝): Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality (⊕⊕⊝⊝): Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality (⊕⊝⊝⊝): We are very uncertain about the estimate.