Growth monitoring and mortality risk in low birthweight infants: a birth cohort study in Burkina Faso

TL;DR

This study in Burkina Faso finds that low birthweight infants who are underweight at two or six months are at high risk of death and that measuring weight gain doesn't improve risk prediction.

Contribution

The study provides new evidence on the mortality risk of underweight low birthweight infants and challenges the use of weight gain as a monitoring tool.

Findings

Low birthweight infants who are underweight at two months have a 3.30 times higher mortality risk.

Measuring weight gain since birth does not better predict mortality than current weight or arm circumference.

Underweight low birthweight infants at six months are not at significantly lower risk than normal birthweight infants.

Abstract

Background: Wasting and underweight in infancy is an increasingly recognised problem but consensus on optimum assessment is lacking. In particular, there is uncertainty on how to interpret anthropometr
y
among low birth weight (LBW) infants who may be growing normally. This research aim
ed to determine growth of infants from birth to two months (around age of vaccination) and the mortality risk of underweight LBW infants compared to normal birth weight (NBW) infants at two and six months age.

Methods: A secondary analysis of a birth cohort of 1103 infants in Burkina Faso was conducted. Anthropometry was performed monthly from 0 to 12 months. We assessed associations with mortality using Cox proportional hazards models and assessed discriminatory values using area under receiver operating characteristics curves.

Results: Eighty-six (7.8%) children died by age one year, 26/86 (30%) and 51/86 (59%) within two and six months, respectively. At age two months, weight gain since birth did not better discriminate mortality risk than current weight-for-age (P=0.72) or mid-upper arm circumference (P=0.21). In total, 227 (21%) LBW infants had increased risk of mortality: adjusted hazards ratio (aHR) 3.30 (95%CI 2.09 to 4.90). Among infants who were underweight at two and six months, LBW infants (64% and 49%, respectively) were not at reduced risk of death compared to NBW infants (aHR 2.63 (95%CI 0.76 to 9.15) and 2.43 (95%CI 0.74 to 7.98), respectively).

Conclusion: Assessing weight gain since birth does not offer advantages over immediate anthropometry for discriminating mortality risk. LBW infants who are later identified as underweight require care to help prevent mortality.

Figures