Table 1.
Sensitivity and subgroup analyses for relative risk (RR) of all cause mortality during infancy
| Stratification variable* | No of trials | RR (95% CI); P value | Tests for heterogeneity I2 (%); Q (P value) | P value for heterogeneity in subgroups | |
|---|---|---|---|---|---|
| Random effects model | Fixed effects model | ||||
| Overall | 6 | 0.92 (0.75 to 1.12); 0.393 | 0.90 (0.80 to 1.02); 0.090 | 54.1; 10.90 (0.053) | NA |
| Attrition: | |||||
| <10% | 4 | 0.89 (0.77 to 1.03); 0.119 | 0.89 (0.78 to 1.01); 0.065 | 14.8; 3.52 (0.318) | |
| ≥10% | 2 | 0.71 (0.21 to 2.36); 0.576 | 1.01 (0.72 to 1.42); 0.939 | 85.4; 6.84 (0.009) | 0.465 |
| Follow-up age (months): | |||||
| ≤6 | 3 | 0.85 (0.73 to 0.98); 0.024 | 0.85 (0.73 to 0.98); 0.024 | 0.0; 1.63 (0.444) | |
| >6 | 3 | 0.92 (0.57 to 1.48); 0.715 | 1.05 (0.83 to 1.31); 0.703 | 71.0; 6.9 (0.032) | 0.123 |
| Maternal postpartum vitamin A supplementation (≥30% mothers): | |||||
| No | 4 | 0.85 (0.63 to 1.16); 0.305 | 0.86 (0.73 to 1.01); 0.062 | 61.2; 7.72 (0.052) | |
| Yes | 2 | 1.01 (0.73 to 1.40); 0.961 | 0.96 (0.80 to 1.16); 0.676 | 58.1; 2.39 (0.122) | 0.374 |
| No of vitamin A doses received: | |||||
| Single | 5 | 0.96 (0.76 to 1.23); 0.767 | 0.97 (0.83 to 1.12); 0.659 | 51.4; 8.23 (0.083) | |
| Multiple | 1 | 0.78 (0.63 to 0.96); 0.021 | 0.78 (0.63 to 0.96); 0.021 | NA | 0.102 |
| Maternal night blindness: | |||||
| <5% | 1 | 1.24 (0.85 to 1.79); 0.262 | 1.24 (0.85 to 1.79); 0.262 | NA | |
| ≥5% | 2 | 0.83 (0.71 to 0.96); 0.014 | 0.83 (0.71 to 0.96); 0.014 | 0.0; 0.61 (0.433) | 0.049 |
| Birth weight specific†: | |||||
| Low birth weight | 3 | 0.76 (0.58 to 1.01); 0.056 | 0.80 (0.69 to 0.93); 0.003 | 52.7; 4.23 (0.121) | 0.380 |
| Other | 3 | 0.78 (0.43 to 1.40); 0.399 | 0.92 (0.70 to 1.20); 0.514 | 63.7; 5.50 (0.064) | |
NA= not applicable.
*Not done for allocation concealment, blinding, trial site, maternal serum retinol and cumulative vitamin A dose received by neonate as all trials were categorised in only one of two strata.
†Restricted to trials depicting results separately for low and non-low birthweight infants. For these data, in Klemm 2008w14 maternal supplementation with either β carotene or synthetic vitamin A had also been given in comparison (placebo) group according to randomised allocation in this nested design.