Factors Associated With Improvements in Mortality and Morbidity Rates of Very-Low-Birth-Weight Infants: A Cohort Study

Objective. The objective of this study was to determine factors contributing to improvements in infant mortality rates (IMR) and composite morbidity-mortality in very-low-birth-weight (VLBW) infants after initiating a new perinatal program in 2009 at Regional One Health (ROH). VLBW infants account for 67% of infant deaths. Design. This is a pre-/postintervention cohort study of prospectively gathered data. Population. VLBW infants delivered at ROH during the 2004 to 2015 study period. Setting. ROH is a Regional Perinatal Center affiliated with the University of Tennessee Health Science Center. Methods. We studied 2364 consecutive VLBW infants. Multivariate models were applied to determine factors contributing significantly to the reduction in the outcome measures as well as trends over time. Main Outcome Measures. Primary outcomes were IMR and composite morbidity-mortality rates. Standardized, risk-adjusted mortality and composite morbidity ratios were also reported as defined by the Vermont Oxford Network. Results. Mortality declined from 15.5% in Pre-Implementation to 13.1% in Post-Implementation (P = .093), corresponding to an 18% reduction in odds. The combined factors of composite morbidity-mortality rate decreased from 55.7% in Pre-Implementation to 43.9% in Post-Implementation (P < .0001), representing a 38% reduction in odds. Standardized, risk-adjusted mortality and composite morbidity ratios improved during the study period from 20% above to 20% below the expected rate. Increases in the administration of antenatal steroids, surfactant administration, cesarean delivery, and perhaps other programmatic changes that were observational and unaccounted in the model were associated with improvements in outcome measures. Conclusions. Decreased mortality and composite morbidity-mortality in VLBW infants delivered at ROH were found following the initiation of a new perinatal program.