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27-05-2012 | Infectious disease | Article

Mixed picture for past decade of very-low-birthweight infant outcomes


Free abstract

MedWire News: Despite declines in mortality and major morbidity rates for very-low-birthweight (VLBW) infants between 2000 and 2009, almost half of all babies born in this weight group still either died or were left with at least one major morbidity in 2009, say researchers.

The findings "highlight the continuing challenges facing these vulnerable patients, their families, and the health professionals who care for them," write Jeffrey Horbar, from the University of Vermont in Burlington, USA, and colleagues in Pediatrics.

In light of VLBW infant mortality declining substantially in the early 1990s then leveling off, Horbar and team sought to identify up-to-date mortality and major morbidity rates in comparable infants during the subsequent decade.

Their study cohort comprised 355,806 infants born under the care of 669 US hospitals, at a weight of 501‑ 1500 g.

Standardized mortality rates fell significantly from 14.3% in 2000 to 12.4% in 2009, report the researchers, with the greatest difference noted among infants weighing 501‑750 g, at 41.8% versus 36.6%.

Major neonatal morbidity rates, including bloodstream and central nervous system infections, necrotizing enterocolitis (NEC) chronic lung disease (CLD), and intraventricular hemorrhage, also fell significantly. Rates of major morbidity were highest in all years for infants weighing 501‑750 g, and decreased with increasing birthweight, they add.

Indeed, the standardized rate fell overall from 46.4% to 41.4%, with only a 1.8% change among these lowest birthweight infants. Also, rates of major morbidities in surviving infants, including early and late infection, CLD, and severe retinopathy of prematurity, significantly decreased between 2000 and 2009.

Rates of the combined outcome of death or at least one major morbidity remained highest in the 501‑750 g birthweight group across all years, even though the overall incidence of this outcome fell in this group, from approximately 91% to 89%.

The percentage decrease in this combined outcome was 4.6% for all VLBW infants during the study period; however, it remained "high," at 49.2% in 2009, report Horbar et al.

"This indicates that for every 22 infants weighing 501 to 1500 g who were cared for in 2009, one fewer infants would have had an unfavorable outcome compared with similar infants cared for in 2000," they remark.

Major neonatal morbidities are concerning, say Horbar and co-workers, because they expose infants to additional therapeutic and surgical interventions, cause distress for families, increase length and cost of hospitalization stay, and are predictive of long-term neurodevelopmental disabilities such as cerebral palsy.

By Sarah Guy

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