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Indian Pediatr 2013;50:
830-831 |
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Follow-up Studies – Beyond Survival
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MKC Nair and *Naveen Jain
Child Development Centre, Medical College, and
*Kerala Institute of Medical Sciences, Thiruvananthapuram, India.
Email: [email protected]
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A dvances in antenatal medicine and neonatal
intensive care, including antenatal corticosteroids, delivery room
resuscitation, surfactant use, improved ventilation techniques, and
nutritional management, have resulted in improved survival rates of
preterm infants. The need to report follow up outcomes of babies who are
born very low birth weight (VLBW) is being increasingly recognized over
the last two decades [1,2]. Similar to many developed countries,
survival of Indian VLBW babies is also improving. Therefore, there is a
paucity of prospectively recorded developmental outcomes from India. The
paper by Modi, et al. [3] published in this issue is a pioneering
effort in this direction. The strengths of the study are detailed
descriptions of care process that make it possible to compare with other
centers. It would have been ideal to compare the outcomes of VLBW babies
from different centers with differences in care process. Comparison with
normal birth weight (NBW) babies has limited novelty. Most studies on
outcomes like this one, are based on single–hospital, small cohorts and
short duration of follow up. A few population cohorts with longer follow
up are published [4,5] but there are very few studies from India [6].
Different authors have used different developmental assessment tools and
reported normal or abnormal at varied ages thus making the comparisons
difficult, hence, the fundamental interest of identifying modifiable
risk factors in care process has not been served.
The Ideal Way to Follow Vlbw Infants?
An expert panel of the American Academy of
Pediatrics, National Institute of Child Health and Human Development,
Vermont Oxford Network, and California Children’s Service, has jointly
put forward an evidence-based recommendation to assess quality of
follow-up for VLBW infants [1]. The panel recommends post-discharge
assessment in a total of 70 indicators in the following areas: general
care, physical health, vision, hearing, speech, and language,
developmental and behavioral assessment; and psychosocial issues. The
panel describes in detail the areas of assessment, timing of tests and
what intervention should be planned in case of a deviation from normal.
National Neonatology Forum (NNF), has also outlined follow-up guidelines
for neonatal intensive care unit (NICU) graduates.
Important Outcome Indicators
Most published reports of neurodevelopmental outcome
in infancy focus primarily on the incidence of severe disability, often
defined as mental retardation, cerebral palsy, epilepsy, blindness,
and/or moderate to severe hearing impairment. This has historically been
the neurodevelopmental outcome of interest owing to the severity of the
developmental impact of these severe and often combined morbidities.
But, interest has shifted to the larger proportion of VLBW infants who
are not severely brain injured, and their outcomes [7]. The most common
impairment seen in VLBW and ELBW infants at 18 and 30 months is
cognitive impairment [4]. Bayley scores of less than 70 (more than 2
standard deviations below the mean) are considered severely impaired.
Reported rates of cognitive impairment throughout childhood range from
14% to 39% at 24 weeks, 10% to 30% at 25 weeks 4% to 24% at less than 26
weeks, to 11% to 18% at less than 29 weeks [8]. At 30 months corrected
age, 30% of children had impaired cognitive functioning. Additionally,
although measures of intelligence in children at school-age provide a
reliable assessment of general cognitive functioning, they do not
identify specific learning disabilities. In addition to impairments in
global cognitive functioning, more subtle cognitive impairments are
often detected only by school age [4,8,9].
Duration of Follow-up
Most large clinical trials in the field of
neonatology now include a measure of neurodevelopmental outcome, but the
optimal age of assessment has not been agreed on. Due to the
administrative challenges of long-term follow-up, including cost,
tracking and feasibility, most authors have published data on shorter
long-term outcomes (18 to 22 months corrected age). There is, now, an
increasing evidence of adverse outcomes into school age and adolescence
[6,7]. Development, neurological examination and vision assessment
should ideally be followed till at least 5-6 years [1].
Why Follow-up?
Recent studies support that a combination of biologic
and environmental factors contribute to survival and outcome of preterm
infants. Factors significantly associated with an increased likelihood
of a favorable outcome for infants 22 to 25 weeks’ gestation who
received intensive care were higher gestational age, higher birth
weight, female gender, singleton, and antenatal steroids, all factors
known at birth [8]. Multiple births are an important risk factor for
both death and neuro-developmental impairment among VLBW infants [8].
Common neonatal morbidities, including bronchopulmonary dysplasia (BPD),
retinopathy of prematurity, necrotizing enterocolitis, and infection,
have also been associated with poor cognitive function and academic
abilities in infancy. Rates of neurodevelopmental impairment at 18 to 22
months corrected age is directly proportional to duration of need for
mechanical ventilation in the NICU. BPD has been implicated as a risk
factor for cerebral palsy in multiple studies [8]. It also has an
independent negative effect on motor outcome at 3 years.
Cranial ultrasound abnormalities - periventricular
leukomalacia (PVL) are the strongest predictors of cerebral palsy. There
is a 3- to 10-fold increased risk of cerebral palsy associated with
cystic PVL [8]. The presence of hydrocephalus may increase the risk by
12.2 times, and the presence of PVL and hydrocephalus by 15.4 times.
It is important to recognize babies at-risk and those
with modifiable factors in their health, so that outcomes can be
improved. Hence, time has come when nations / regions (not just one
hospital) must record outcomes of all preterm / VLBW babies till at
least school age. They must also record variables likely to be
associated with outcomes and care process. This will pave the way
forward to improving outcomes of these at-risk babies we are saving.
Competing interests: None stated; Funding:
Nil.
References
1. Wang CJ, McGlynn EA, Brook RH, Leonard CH, Piecuch
RE, Hsueh SI, Schuster MA. Quality-of-care indicators for the
neurodevelopmental follow-up of very low birth weight children: results
of an expert panel process. Pediatrics. 2006;117:2080-92.
2. Bracewell M, Marlow N. Patterns of motor
disability in very preterm children. Ment Retard Dev Disabil Res Rev.
2002;8:241-8.
3. Modi M, Saluja S, Kler M, Batra A, Kaur A, Garg P,
et al. Growth and Neuro-developmental outcome of VLBW infants at
1 year corrected age. Indian Pediatr. 2012; Epub 1-11.
4. Bhutta AT, Cleves MA, Casey PH, Cradock MM, Anand
KJ. Cognitive and behavioral outcomes of school-aged children who were
born preterm: a meta-analysis. JAMA. 2002;288:728-37.
5. Marlow N, Wolke D, Bracewell MA, Samara M; EPICure
Study Group. Neurologic and developmental disability at six years of age
after extremely preterm birth. N Engl J Med. 2005;352:9-19.
6. Mukhopadhyay K, Malhi P, Mahajan R, Narang A.
Neurodevelopmental and behavioral outcome of very low birth weight
babies at corrected age of 2 years. Indian J Pediatr. 2010;77:963-7.
7. Breslau N, Chilcoat HD, Johnson EO, Andreski P,
Lucia VC. Neurologic soft signs and low birthweight: their association
and neuropsychiatric implications. Biol Psychiatry. 2000;47:71-9.
8. Stephens BE, Vohr BR. Neurodevelopmental outcome
of the premature infant. Pediatr Clin North Am. 2009;56:631-46.
9. Msall ME, Buck GM, Rogers BT, Catanzaro NL.
Kindergarten readiness after extreme prematurity. Am J Dis Child.
1992;146:1371-5.
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