Table 2. Primary and Secondary Outcomes in Children at 2 Years’ Corrected Agea.
| No./total (%) | Risk difference (95% CI), % | Relative risk (95% CI) | P valueb | |||
|---|---|---|---|---|---|---|
| Magnesium sulfate | Placebo | Unadjusted | Adjustedb | |||
| Primary outcome | ||||||
| Death or cerebral palsy (loss of motor function and abnormalities of muscle tone and power) at 2 yc | 23/691 (3.3) | 18/674 (2.7) | 0.61 (−1.27 to 2.50) | 1.22 (0.66 to 2.27) | 1.19 (0.65 to 2.18) | .57 |
| Components of the primary outcome | ||||||
| Any deathd | 12/837 (1.4) | 7/796 (0.9) | 0.48 (−0.62 to 1.58) | 1.51 (0.58 to 3.90) | 1.50 (0.58 to 3.86) | .40 |
| Death of live-born infant before hospital discharge | 5/837 (0.6) | 4/796 (0.5) | 0.09 (−0.62 to 0.81) | NE | NE | >.99e |
| Death after discharge and <2 y | 7/837 (0.8) | 3/796 (0.4) | 0.38 (−0.42 to 1.18) | NE | NE | .34e |
| Cerebral palsyf | 11/679 (1.6) | 11/667 (1.7) | −0.03 (−1.39 to 1.33) | 0.98 (0.43 to 2.25) | 0.98 (0.43 to 2.23) | .96 |
| Sensitivity analysis for primary outcome | ||||||
| Death or cerebral palsyc,g | 23/823 (2.8) | 19/785 (2.4) | 0.36 (−1.25 to 1.97) | 1.15 (0.62 to 2.11) | 1.15 (0.63 to 2.09) | .65 |
| Secondary childhood outcomes | ||||||
| Death or any neurosensory disabilityh | 146/631 (23) | 165/630 (26) | −3.37 (−8.45 to 1.71) | 0.87 (0.71 to 1.07) | 0.87 (0.71 to 1.06) | .17 |
| Death or major neurosensory disabilityi,j | 57/629 (9.1) | 52/624 (8.3) | 0.44 (−2.89 to 3.76) | 1.05 (0.72 to 1.53) | 1.00 (0.69 to 1.45) | .99 |
| Severity of cerebral palsyk,l | ||||||
| None | 668/679 (98) | 656/667 (98) | ||||
| Mildf | 5/679 (0.7) | 7/667 (1.1) | −0.03 (−1.39 to 1.33) | 0.98 (0.43 to 2.25) | 0.98 (0.43 to 2.23) | .96 |
| Moderate | 5/679 (0.7) | 3/667 (0.5) | 0.28 (−0.63 to 1.20) | NE | NE | .75e |
| Severe | 1/679 (0.2) | 1/667 (0.2) | 0 (−0.41 to 0.41) | NE | NE | >.99e |
| Blindnessm | 1/679 (0.2) | 0/667 | −0.16 (−8.61 to 8.30) | NE | NE | >.99e |
| Deafnessn | 3/679 (0.4) | 5/667 (0.8) | −0.05 (−0.87 to 0.76) | NE | NE | .50e |
| Cognitive or language developmental delayo | 116/625 (19) | 128/624 (21) | −2.34 (−7.02 to 2.34) | 0.89 (0.69 to 1.13) | 0.88 (0.70 to 1.11) | .27 |
| Severity of cognitive or language developmental delayl,p | ||||||
| None | 509/625 (81) | 496/624 (80) | ||||
| Mild | 77/625 (12) | 92/624 (15) | −2.34 (−7.02 to 2.34) | 0.89 (0.69 to 1.13) | 0.88 (0.70 to 1.11) | .27 |
| Moderateq | 29/625 (4.6) | 32/624 (5.1) | 0.14 (−2.64 to 2.93) | 1.02 (0.64 to 1.63) | 1.00 (0.63 to 1.58) | .98 |
| Severe | 10/625 (1.6) | 4/624 (0.6) | 0.90 (−0.35 to 2.16) | NE | NE | .18e |
| Motor developmental delayj,r | 52/643 (8.1) | 67/635 (10.6) | −2.29 (−5.68 to 1.11) | 0.79 (0.55 to 1.12) | 0.78 (0.55 to 1.11) | .17 |
| Severity of motor developmental delayl,p | ||||||
| None | 591/643 (92) | 568/635 (89) | ||||
| Mildj | 34/643 (5.3) | 54/635 (8.5) | −2.29 (−5.68 to 1.11) | 0.79 (0.55 to 1.12) | 0.78 (0.55 to 1.11) | .17 |
| Moderateq | 11/643 (1.7) | 10/635 (1.6) | 0.86 (−0.90 to 2.63) | 1.42 (0.69 to 2.95) | 1.44 (0.70 to 2.95) | .33 |
| Severe | 7/643 (1.1) | 3/635 (0.5) | 0.62 (−0.35 to 1.58) | NE | NE | .34e |
| Developmental delays | ||||||
| Any | 132/624 (21) | 149/622 (24) | −2.96 (−7.90 to 1.98) | 0.88 (0.70 to 1.09) | 0.87 (0.70 to 1.08) | .20 |
| Severe | 12/623 (1.9) | 7/621 (1.1) | 0.78 (−0.67 to 2.22) | 1.66 (0.64 to 4.29) | 1.64 (0.63 to 4.23) | .31 |
| Required health services after hospital discharge | ||||||
| Hospital readmission | 261/702 (37) | 272/663 (41) | −3.27 (−8.65 to 2.12) | 0.92 (0.80 to 1.06) | 0.94 (0.82 to 1.07) | .34 |
| Any service | 241/691 (35) | 242/661 (37) | −1.36 (−6.79 to 4.07) | 0.96 (0.83 to 1.12) | 0.98 (0.85 to 1.14) | .84 |
| Childhood respiratory morbidityt | 226/702 (32) | 230/663 (35) | 2.20 (7.50 to 3.09) | 0.94 (0.83 to 1.12) | 0.98 (0.85 to 1.14) | .74 |
| Asthma or wheezing | 159/702 (23) | 158/663 (24) | −0.91 (−5.68 to 3.48) | 0.96 (0.78 to 1.18) | 1.02 (0.84 to 1.24) | .84 |
Abbreviation: NE, not estimable.
The analyses accounted for a within-participant clustering effect. The secondary outcomes of Child Behavior Check List scores (eTable 2), body size (eTable 3), and blood pressure (eTable 4) appear in Supplement 3.
Adjusted for hospital site, gestational age at entry, plurality, sex of the infant, language spoken at home, and socioeconomic status.
Defined as stillbirth, death of live-born infant before hospital discharge, or death after hospital discharge before 2 years’ corrected age or diagnosis of cerebral palsy. Adjusted for hospital site, gestational age at entry, plurality, sex of the infant, and language spoken at home.
Adjusted for hospital site, gestational age at entry, plurality, and sex of the infant.
Calculated using the Fisher exact test.
Adjusted for hospital site, gestational age at entry, and plurality.
Data were reported from all sources (pediatrician, psychometrist, caregiver questionnaires, and caregiver).
Death defined as stillbirth, death of live-born infant before hospital discharge, or death after hospital discharge before 2 years’ corrected age. Any neurosensory disabilities were defined as those that include the neurosensory impairments of cerebral palsy (Gross Motor Function Classification System [GMFCS] levels 1-5), blindness (corrected visual acuity worse than <6/60 in the better eye), deafness (hearing loss requiring hearing aids or a cochlear implant), or any developmental delay (standardized score >1 SD below the mean).
Any death before 2 years’ corrected age or severe and moderate disability, including blindness (corrected visual acuity worse than <6/60 in the better eye), deafness requiring hearing aids, moderate or severe cerebral palsy (GMFCS levels 2-5), or developmental delay or intellectual impairment (standardized score >2 SD below the mean).
Adjusted for hospital site, gestational age at entry, plurality, sex of the infant, and language spoken at home.
Categorized as mild (GMFCS level 1), moderate (GMFCS level 2 or 3), or severe (GMFCS level 4 or 5).
Data are from separate log-binomial models (ie, mild vs none; moderate vs none or mild; and severe vs none, mild, or moderate) because a proportional odds assumption was not met.
Defined as visual acuity in both eyes worse than 6/60.
Defined as requiring hearing aids or a cochlear implant.
Defined by a standardized score greater than 1 SD below the mean (ie, <−1 SD).
Categorized as mild (standardized score of −2 SD to <−1 SD), moderate (standardized score of −3 SD to <−2 SD), or severe (standardized score <−3 SD).
Adjusted for gestational age at entry, plurality, sex of the infant, and language spoken at home.
Defined by a standardized score greater than 1 SD below the mean (<−1 SD).
Cognitive delay, language delay, or motor developmental delay.
Based on parental report of asthma, wheezing, or respiratory tract infection.