Continually Improving Outcomes for Very Low Birth Weight Infants

In this edition of Pediatrics, Lee et al¹  present trends in survival without major morbidity as well as trends in individual morbidities in very low birth weight infants with birth weights of 401 to 1500 g or gestational ages between 22 and 29 weeks born between 2008 and 2017. In this cohort of almost 50 000 infants across 143 hospitals belonging to the California Perinatal Quality Care Collaborative (CPQCC), survival without major morbidity consistently increased from 62.0% to 67.2%. The largest improvements in morbidity were seen in infants with necrotizing enterocolitis and nosocomial infection. Bronchopulmonary dysplasia rates did not change significantly.

There has been a steady stream of reports of decreased neonatal morbidity and mortality since the 1990s. Most, but not all, networks have reported these widespread improvements.^2–5  The Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network’s report of outcomes in a nearly identical population studied between 1993 and 2012 demonstrated increased use of evidence-based practices such as antenatal corticosteroids and adoption of less invasive ventilation as well as improvements in mortality, particularly in the smallest and least mature infants with a gestational age range of 23 to 24 weeks.^2,6  Although survival without major morbidity improved ∼2% per year for infants of 25 to 28 weeks’ gestation, morbidity in survivors of 23 to 24 weeks’ gestation remained high with no change over time. Between 2000 and 2009, 669 North American centers in the Vermont Oxford Network, which includes CPQCC members, reported a decrease in mortality for infants weighing 501 to 1500 g from 14.3% to 12.4%.³  Major morbidity in survivors decreased from 46.4% to 41.4%. Multiple morbidities, including late-onset infection, severe retinopathy of prematurity, severe intraventricular hemorrhage, and necrotizing enterocolitis, decreased during this time frame as well.

Consistent with other reports, Lee et al¹  note a concerning lack of progress in reducing the incidence of bronchopulmonary dysplasia. This is despite an increase in evidence-based practices, including an increased use of antenatal steroids and increased use of less invasive ventilatory support.^4,7  Why tremendous improvements have occurred in nosocomial infection and other serious morbidities yet bronchopulmonary dysplasia remains refractory is indeed intriguing.

Lee et al¹  note a decrease in the percentage of infants who survived with multiple morbidities. Obviously, relatively short-term hospital outcomes do not directly address the larger issue of long-term morbidity and outcomes. However, among the morbidities that were reported, several are clearly associated with worse developmental outcome. Schmidt et al⁸  report that bronchopulmonary dysplasia, severe retinopathy of prematurity, and ultrasound evidence of brain injury are all associated with worse developmental outcomes, and infants who have >1 of these outcomes do the worst. It is unfortunate that bronchopulmonary dysplasia, 1 of these 3 drivers of poor outcome, has remained unchanged.

Lee et al¹  do not report on which of these preterm infants have benefitted most from these improvements. Other reports from large neonatal networks suggest that improved survival is greatest in the least mature infants.^2,3  However, these gains are somewhat diminished by the still substantial burden of serious morbidities. Care practices in the smallest of these infants (22–23 weeks’ gestation) vary greatly, from the decision to resuscitate to the provision of antenatal care, including willingness to perform cesarean delivery and administer corticosteroids for lung maturation. Although there is a paucity of evidence from trials regarding the impact of these practices in this extremely preterm population, a coordinated approach between obstetric providers and the neonatal team seems likely to confer the greatest benefit to these infants.⁹ 

Lastly, it is heartening to see that the variation in outcomes has decreased across centers. This implies that our entire community is doing better, not just exceptional hospitals. However, it must be noted that significant differences persist in the outcomes in various racial and ethnic groups. Boghossian et al¹⁰  note that in a similar population, disparities for certain care practices, such as antenatal steroids, have narrowed over time for minority infants, as have other outcomes. Despite these improvements, outcomes such as hypothermia, mortality, necrotizing enterocolitis, late-onset sepsis, and severe intraventricular hemorrhage remain elevated, especially among African American infants.

Improved outcomes for extremely preterm infants have occurred despite a lack of major generalizable breakthroughs in care that are proven by clinical trials. Hopefully, a commitment to improvement such as the CPQCC has become part of the culture of neonatal intensive care. Horbar et al¹¹  presented an interesting analysis that brings this point home. With the exception of chronic lung disease, 75% of NICUs achieved rates of performance that are as good as or better than the top quartile of the benchmark performances from 8 years earlier. Further improvements are clearly within our grasp. However, it is imperative that these improvements extend to all groups and all centers.

CPQCC

California Perinatal Quality Care Collaborative