Annex 1GRADE “Summary of findings” tables
Intermittent use of iron supplements versus placebo or no intervention in children 2 months –12 years of age
Patient or population: Children under 12 years of age
Settings: Community settings
Intervention: Intermittent supplementation with iron alone or with other micronutrients
Comparison: Placebo or no intervention
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| Outcomes | Relative effect
(95% CI) | Number of participants
(studies) | Quality of the evidence
(GRADE)* | Comments |
|---|
| Anaemia (haemoglobin below a cut-off defined by the trialists, taking into account the age and altitude) | RR 0.51
(0.37–0.72) | 1824
(10 studies) | ⊕⊕⊕⊖
moderate1 | |
| Haemoglobin (g/l) | MD 5.20
(2.51–7.88) | 3032
(19 studies) | ⊕⊕⊖⊖
low2,3 | |
| Iron deficiency | RR 0.24
(0.06–0.91) | 431
(3 studies) | ⊕⊖⊖⊖
very low2,3,4 | |
| Iron deficiency anaemia | Not estimable | 0
(0 studies) | See comment | None of the trials reported on this outcome |
| Ferritin (μg/l) | MD 14.17
(3.53–24.81) | 550
(5 studies) | ⊕⊕⊖⊖
low2,3 | |
| All-cause mortality | Not estimable | 0
(0 studies) | See comment | None of the trials reported on this outcome |
CI, confidence interval; RR, risk ratio; MD, mean difference.
- *
GRADE Working Group grades of evidence:
High quality: We are very confident that the true effect lies close to that of the estimate of the effect.
Moderate quality: We have moderate confidence in the effect estimate. The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low quality: Our confidence in the effect estimate is limited. The true effect may be substantially different from the estimate of the effect.
Very low quality: We have very little confidence in the effect estimate. The true effect is likely to be substantially different from the estimate of the effect.
- 1
There was high statistical heterogeneity. Given the large and consistent effect (RR 0.51; 95% CI 0.37-0.72), the authors have refrained from downgrading even though three of 10 studies were at high risk of bias.
- 2
High statistical heterogeneity but results were consistent.
- 3
Some studies lacked blinding and clear methods of allocation.
- 4
Wide confidence intervals.
Note: For cluster-randomized trials, the analyses only include the estimated effective sample size, after adjusting the data to account for the clustering effect.
For details of studies included in the review, see reference (17).
Intermittent versus daily use of iron supplements in children under 12 years of age
Patient or population: Children under 12 years of age
Settings: Community settings
Intervention: Intermittent supplementation with iron alone or with other micronutrients
Comparison: Daily supplementation with iron alone or with other micronutrients
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| Outcomes | Relative effect
(95% CI) | Number of participants
(studies) | Quality of the evidence
(GRADE)* | Comments |
|---|
| Anaemia (haemoglobin below a cut-off defined by the trialists, taking into account the age and altitude) | RR 1.23
(1.04–1.47) | 980
(6 studies) | ⊕⊕⊖⊖
low1,2 | |
| Haemoglobin (g/l) | MD −0.60
(–1.54, 0.35) | 2834
(19 studies) | ⊕⊕⊖⊖
low1,3 | |
| Iron deficiency | RR 4.00
(1.23–13.05) | 76
(1 study) | ⊕⊖⊖⊖
very low4 | Only one study reported on this outcome |
| Iron deficiency anaemia | Not estimable | 0
(0 studies) | See comment | None of the trials reported on this outcome |
| Ferritin (μg/l) | MD −0.49
(–9.42 to 1.05) | 902
(10 studies) | ⊕⊕⊖⊖
low1,3 | |
| All-cause mortality | Not estimable | 0
(0 studies) | See comment | None of the trials reported on this outcome |
CI, confidence interval; RR, risk ratio; MD, mean difference.
- *
GRADE Working Group grades of evidence:
High quality: We are very confident that the true effect lies close to that of the estimate of the effect.
Moderate quality: We have moderate confidence in the effect estimate. The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low quality: Our confidence in the effect estimate is limited. The true effect may be substantially different from the estimate of the effect.
Very low quality: We have very little confidence in the effect estimate. The true effect is likely to be substantially different from the estimate of the effect.
- 1
Some studies lacked blinding and clear methods of randomization and allocation.
- 2
Wide confidence intervals.
- 3
High heterogeneity but results were mostly consistent.
- 4
Only one trial with unclear methods to generate the random sequence and conceal the allocation. Wide confidence intervals.
Note: For cluster-randomized trials, the analyses only include the estimated effective sample size, after adjusting the data to account for the clustering effect.
For details of studies included in the review, see reference (17).
