Study-level characteristic | Mortality <6 months | Mortality <12 months | ||||||
n* | Included studies† | RR (95% CI) | Meta-regression p values | n* | Included studies† | RR (95% CI) | Meta-regression‡ p values | |
Overall | 11 | a–k | RE 0.97 (0.89 to 1.06) | 10 | a–h, j, k | RE 1.00 (0.93 to 1.08) | ||
Geographic region | ||||||||
Asia | 5 | a, f, i, j, k | RE 0.87 (0.77 to 0.98) | 0.009 | 4 | a, f, j, k | RE 0.91 (0.80 to 1.03) | 0.013 |
Africa | 6 | b, c, d, e, g, h | RE 1.06 (0.98 to 1.15) | 6 | b, c, d, e, g, h | RE 1.07 (1.00 to 1.15) | ||
Maternal vitamin A deficiency level | ||||||||
Moderate/severe | 3 | a, f, i | RE 0.87 (0.80 to 0.94) | 0.012 | 2 | a, f | RE 0.91 (0.83 to 1.00) | 0.033 |
None/mild | 7 | b, c, d, e, g, h, j | RE 1.05 (0.96 to 1.15) | 7 | b, c, d, e, g, h, j | RE 1.06 (0.98 to 1.15) | ||
Maternal postnatal vitamin A programme | ||||||||
No | 7 | a, d, e, g, i, j, k | RE 0.93 (0.82 to 1.05) | 0.392 | 6 | a, d, e, g, j, k | RE 0.99 (0.88 to 1.12) | 0.768 |
Yes | 4 | b, c, f, h | RE 1.00 (0.89 to 1.13) | 4 | b, c, f, h | RE 1.02 (0.91 to 1.13) | ||
Mortality enrolment to 6 months (control group) | ||||||||
≥30/1000 | 6 | a, e, f, h, i, k | RE 0.91 (0.85 to 0.98) | 0.021 | 5 | a, e, f, h, k | RE 0.97 (0.89 to 1.04) | 0.181 |
<30/1000 | 5 | b, c, d, g, j | RE 1.08 (0.95 to 1.24) | 5 | b, c, d, g, j | RE 1.06 (0.93 to 1.22) | ||
Ratio of mortality 6–12 months | ||||||||
≥75% | 6 | a, e, f, h, j, k | RE 0.92 (0.84 to 1.01) | 0.019 | 6 | a, e, f, h, j, k | RE 0.96 (0.86 to 1.06) | 0.065 |
<75% | 4 | b, c, d, g | RE 1.11 (1.00 to 1.22) | 4 | b, c, d, g | RE 1.08 (0.99 to 1.17) | ||
Proportion given first DPT by 6 months | ||||||||
<93% | 4 | a, e, I, k | RE 0.91 (0.82 to 1.00) | 0.209 | 3 | a, e, k | RE 0.96 (0.89 to 1.03) | 0.640 |
≥93% | 5 | b, c, d, f, g | RE 1.03 (0.91 to 1.18) | 5 | b, c, d, f, g | RE 1.03 (0.91 to 1.15) | ||
Proportion of mothers with no schooling | ||||||||
≥32% | 4 | a, f, g, i | RE 0.88 (0.80 to 0.96) | 0.041 | 3 | a, f, g | RE 0.93 (0.85 to 1.01) | 0.083 |
<32% | 5 | b, c, d, h, j | 1.04 (0.92 to 1.18) | 5 | b, c, d, h, j | RE 1.06 (0.95 to 1.18) |
*Number of studies included in subgroup analysis.
†Studies are noted as follows: (a) Mazumder et al 22; (b) Edmond et al 24 ; (c) Masanja et al 23; (d) Benn et al 19; (e) Benn et al 17; (f) Klemm et al 13; (g) Benn et al 18; (h) Malaba et al 16 and Humphrey et al 15; (i) Rahmathullah et al 14; (j) Humphrey et al 12; (k) Soofi et al 25.
‡P values from univariate meta-regression.
DPT, dipropyltryptamine; RE, random effects; RR, rate ratio.