We read with much interest the research paper on growth and
neurodevelopmental outcomes of VLBW infants at 1 year
corrected age by Modi, et al. [1]. There are indeed,
not many follow-up studies from India featuring long term
outcomes of preterm infants. The present study, although a
step in this direction, does not add substantially to the
existing knowledge considering the modest sample size and
follow-up timeline of 1 year. Following points need to be
highlighted.
The sample size calculation is not
mentioned and the blinding of the developmental
paediatrician is not specified.
Almost half the infants (46%) in the
cohort are small for gestational age (SGA). These babies are
well known to have different outcomes than their AGA
counterparts (whether term or preterm) in both short and
long term [2-4]. Segregating SGA from AGA and analyzing the
results separately would have given more credibility to the
results, especially in this scenario wherein, there is an
almost 3 week difference between mean gestational age of AGA
and SGA infants, thereby complicating the results further!
Also, comparing VLBW-SGA babies with NBW-SGA babies would be
more meaningful as also comparing VLBW-AGA babies with
NBW-AGA babies. The authors mention that there was growth
catch-up shown by all babies in all anthropometric
parameters. The difference in catch-up growth, between AGA
and SGA babies if any, needs to be highlighted.
The authors have drawn conclusions that
the developmental indices are significantly lower in VLBW
babies than NBW counterparts at 1 year corrected age.
Firstly, the sample size seems too small to draw any such
conclusions. Secondly, the assessment was made at 1 year of
age when some of the components of DASII scale which can
only be performed for example at 18-24 months, cannot be
applied (which the author also points out). Therefore, the
significance cannot be judged appropriately. Thirdly, the
statistical significance found in the study is unlikely to
be of any clinical relevance as all the babies who were
assessed scored above 90 on DASII scale. Similarly, the head
size of – 1 SD although on the smaller side, but is within
normal limits. Developmental indices of > 90 are also within
normal limits. Therefore it’s very difficult to draw the
conclusion of poor neurological outcome from the available
data.
References
1. Modi M, Saluja S, Kler N, Batra A,
Kaur A, Garg P, et al. Growth and neurodevelopmental
outcome of VLBW infants at 1 year corrected age. Indian
Pediatr. 2013;50:573-7.
2. Arcangeli T, Thilaganathan B, Hooper
R, Khan KS, Bhide A. Neurodevelopmental delay in small
babies at term: a systematic review. Ultrasound Obstet
Gynecol. 2012;40: 267-75.
3. Qiu X, Lodha A, Shah PS, Sankaran K,
Seshia MM, Yee W, et al. Neonatal outcomes of small
for gestational age preterm infants in Canada. Am J
Perinatol. 2012;29:87-94.
4. Gutbrod T, Wolke D, Soehne B, Ohrt B, Riegel K.
Effects of gestation and birth weight on the growth and
development of very low birthweight small for gestational
age infants: a matched group comparison. Arch Dis Child
Fetal Neonatal Ed. 2000;82:F208-14.