Table 5.
Subgroup interaction analyses for recombinant human erythropoietin on Mental Development Index < 70
| Subgroups | Placebo | rhEPO | RR (95% CI) | Interaction p value |
|---|---|---|---|---|
| Sex | ||||
| Male | 12/75 (16.0) | 7/72 (9.7) | 0.565 (0.209–1.528) | |
| Female | 7/49 (14.3) | 2/53 (3.8) | 0.235 (0.046–1.193) | |
| Total | 0.429 (0.186–0.989) | 0.361 | ||
| Gestational age | ||||
| < 28 weeks | 2/15 (13.3) | 3/19 (15.8) | 1.219 (0.176–8.423) | |
| 28–296/7 weeks | 9/64 (14.1) | 2/60 (3.3)* | 0.211 (0.044–1.019) | |
| 30–32 weeks | 8/45 (17.8) | 4/46 (8.7) | 0.440 (0.123–1.583) | |
| Total | 0.429 (0.186–0.989) | 0.366 | ||
| Birth weight, g | ||||
| < 1000 | 1/12 (8.3) | 2/15 (13.3) | 1.692 (0.135–21.270) | |
| 1000–1499 | 14/93 (15.1) | 5/91 (5.5)* | 0.328 (0.113–0.952) | |
| ≥ 1500 | 4/19 (21.1) | 2/19 (10.5) | 0.441 (0.070–2.761) | |
| Total | 0.429 (0.186–0.989) | 0.470 | ||
| Degree of IVH | ||||
| Grade I–II | 14/112 (12.5) | 7/120 (5.8) | 0.434 (0.168–1.118) | |
| Grade III–IV | 5/12 (41.7) | 2/5 (40.0) | 0.933 (0.111–7.820) | |
| Total | 0.429 (0.186–0.989) | 0.516 |
Data are presented as n/N (%) unless otherwise indicated. The p value is for the interaction analysis in subgroups using the Mantel–Haenszel test. p < 0.05 was considered statistically significant
CI confidence interval, IVH intraventricular hemorrhage, rhEPO recombinant human erythropoietin, RR relative risk
*p < 0.05 using Fisher’s exact test to compare the placebo and rhEPO groups