Growth phenotypes of very low birth weight infants for prediction of neonatal outcomes from a Brazilian cohort: comparison with INTERGROWTH

OBJECTIVE

To assess the predictive value of selected growth phenotypes for neonatal morbidity and mortality in preterm infants < 30 weeks and to compare them with INTERGROWTH-21^st (IG21).

METHOD

Retrospective analysis of data from the Brazilian Neonatal Research Network (BNRN) database for very low birth weight (VLBW) at 20 public tertiary-care university hospitals.

OUTCOME

the composite neonatal morbidity and mortality (CNMM) consisted of in-hospital death, oxygen use at 36 weeks, intraventricular hemorrhage grade 3 or 4, and Bell stage 2 or 3 necrotizing enterocolitis. Selected growth phenotypes: small-for-gestational-age (SGA) defined as being < 3^rd (SGA3) or 10^th (SGA10) percentiles of BW, and large-for-gestational-age (LGA) as being > 97^th percentile of BW. Stunting as being < 3^rd percentile of the length and wasting as being < 3^rd percentile of BMI. Single and multiple log-binomial regression models were fitted to estimate the relative risks of CNMM, comparing them to IG21.

RESULTS

4,072 infants were included. The adjusted relative risks of CNMM associated with selected growth phenotypes were (BNRN/IG21): 1.45 (0.92-2.31)/1.60 (1.27-2.02) for SGA; 0.90 (0.55-1.47)/1.05 (0.55-1.99) for LGA; 1.65 (1.08-2.51)/1.58 (1.28-1.96) for stunting; and 1.48 (1.02-2.17) for wasting. Agreement between the two references was variable. The growth phenotypes had good specificity (>95%) and positive predictive value (70-90%), with poor sensitivity and low negative predictive value.

CONCLUSION

The BNRN phenotypes at birth differed markedly from the IG21 standard and showed poor accuracy in predicting adverse neonatal outcomes.