Table 1. Summary of Studies Reporting Risk Factor Analyses for Global Cognitive Impairment in Children Born Very Preterm or With Very Low Birth Weight Assessed at Younger Than 5 Years.
| Source (Study Identifier) | Country and Recruitment Period | Age at Assessment, y | GA, wk/BW, g | Design and Participants | Survivors Assessed, No. (%)a | Outcome Measure, Continuous Unless Otherwise Specified | Method for Dealing With Untestable Children | Significant Risk Factors for Poorer Outcome at P < .05 in Final Model |
|---|---|---|---|---|---|---|---|---|
| Tommiska et al,20 2003 (A) | Finland 1996-1997 | 1.5 | <1000 g | PC of infants born and treated in a single-center NICU (Helsinki) and enrolled for the national routine FUP | 78 (94) | MDI score from BSID-II | Excluded if severe developmental problem (n = 3) or exhaustion (n = 2) | No. of days from January 1, 1996, to birth |
| Vohr et al,21 2005 (B) | United States 1993-1998 | 1.5-1.8 | <33 wk and <1000 g | PC of infants admitted to the NICU of 12 centers participating in the multicenter NICHD NRN routine FUP | 3785 (80) | MDI score from BSID-II (<70 vs ≥70), blinded assessment | Excluded if test not completed (n = 118) | Birth epoch (1993-1994 vs 1995-1996), lower BW, BPD, any high-frequency ventilation, IVH 3-4, male sex, lower maternal education, no private insurance, multiple pregnancy, nonwhite race/ethnicity, outborn,b PVL, PN corticosteroid use |
| Adams-Chapman et al,22 2013 (C) | United States 2006-2008 | 1.5-1.8 | <1000 g | PC of infants admitted to the NICU of 20 centers participating in the multicenter NICHD NRN routine FUP | 1477 (91) | Cognitive Composite Score from BSID-III, blinded assessment | Assigned a score of 54 if severely delayed (n = 39) | Lower BW, black race/ethnicity, dysfunctional feeding, GMFCS≥2, non–English speaking, male sex, lower maternal education, MV days, multiple pregnancy, NEC 2-3, no private insurance, IVH 3-4 or PVL |
| Stoelhorst et al,23 2003 (D)c | Netherlands 1996-1997 | 2 | <32wk | PC of all live births in 3 Dutch health regions comprising 9% of the population | 146 (62) | MDI score from BSID-I | Assigned a score of 50 if severely disabled (n = 3), otherwise excluded (n = 5) | Male sex, lower maternal age, non-Dutch, PN corticosteroid use, SGA |
| Helderman et al,24 2012 (E) | United States 2002-2004 | 2 | <28wk | PC of all live births in 14 centers in 5 states (ELGAN study) | 921 (77) | MDI score from BSID-II (<55 and 55-69 vs ≥70), blinded assessment | Excluded if GMFCS ≥1 (n = 83) | BW <− 2 SDs, BMI >30, male sex, lower maternal education, nonwhite race/ethnicity |
| Toome et al,25 2013 (F) | Estonia 2007 | 2 | <32wk | PC of all live births in Estonia enrolled in the national neonatal research routine FUP | 155 (99) | Cognitive Composite Score from BSID-III (<70 vs ≥70) | Assigned a score of −4 SDs below the mean (No. not reported) | IVH 3-4 or PVL 2-4, NEC 2-3 |
| Wood et al,26 2005 (G) | United Kingdom and Republic of Ireland 1995 | 2.5 | <26wk | PC of all live births in the United Kingdom and Republic of Ireland (EPICure study) | 196 (64) | MDI score from BSID-II | Excluded if MDI <55 or functional motor disability (n = 52) | Afro-Caribbean race/ethnicity, no AN corticosteroid use, BPD, male sex, lowermaternal education, PROM |
| Messinger et al,27 2010 (H)d | United States 1999-2001 | 2.5 | <1000 g | Infants admitted to the NICU of 12 centers participating in the multicenter NICHD NRN routine FUP and enrolled in a glutamine supplementation RCT | 539 (47) | MDI score from BSID-II | Excluded if test uncompleted (No. not reported) | BW ≤750 g, higher maternal income, higher MDI at 18 mo |
Abbreviations: AN, antenatal; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); BPD, bronchopulmonary dysplasia; BSID, Bayley Scales of Infant Development51; BW, birth weight; ELGAN, Extremely Low Gestational Age Newborns; FUP, follow-up; GA, gestational age; GMFCS, Gross Motor Functional Classification System68; IVH, intraventricular hemorrhage; MDI, Mental Developmental Index from the BSID; MV, mechanical ventilation; NEC, necrotizing enterocolitis; NICU, neonatal intensive care unit; NICHD NRN, National Institute of Child Health and Human Development Neonatal Research Network; PC, prospective cohort; PN, postnatal; PROM, prolonged rupture of membranes; PVL, periventricular leukomalacia; RCT, randomized clinical trial; SGA, small for gestational age.
Percentage of survivors assessed for outcome measure specified.
Born outside of the hospital where they were admitted to the NICU.
Two models for motor skills reported, with the model based on 2-year outcome included and the model based on 1.5-year outcome not included.
Several models for cognitive function fitted, with the full model adjusting for 18-month MDI and Behavior Rating Scale total score included.