Where a very preterm baby is born may affect survival odds and hospital time

Nearly one in every 10 infants in the United States is born preterm, or before 37 weeks of gestational age, according to the Centers for Disease Control and Prevention. Infants born with very low birthweights—under 3.3 pounds at birth—are disproportionately very preterm—29-weeks gestation or earlier. These infants make up 1% of births, but account for more than half of infant deaths in the United States each year. The mortality rate for infants born very preterm, and length of hospital stay, may vary across health systems, according to a new study by researchers at Penn State.

Led by Jeannette Rogowski, professor of health policy and administration at Penn State, the team found that where a very preterm baby is born or receives care immediately after birth can increase or decrease the chance of survival by two percentage points. The findings, which the researchers said demonstrate potential for quality improvement among the nation’s neonatal intensive care units (NICUs) in health systems, were published in JAMA Network Open.

A previous study led by Rogowski found that approximately 84% of very preterm infants are born in a hospital that is part of a consolidated multi-hospital system—a system with two or more hospitals. Among pediatric patients, very preterm infants are the most vulnerable population. However, the variation in the quality of care for very preterm infants across health systems was unknown. This study was the first to address this question, according to Rogowski.

“For the past several decades, research has looked at NICUs in terms of how quality care is provided and how patient outcomes can be optimized,” Rogowski said.

“Not only is the rate of mortality in these babies high, but the rate of morbidity as well. They are at a greater risk of blindness, brain hemorrhages and other serious complications. The care received at birth has the potential to alter the health trajectory of a baby born very preterm, which can have lifetime consequences for the most vulnerable infants.”

Nearly 90% of very low birthweight infants—babies who weigh less than 3.3 pounds and most of whom are born before 37 weeks of gestation—admitted to a NICU in the United States are enrolled in a global network of NICUs, the Vermont Oxford Network, which is dedicated to improving the quality and safety of care for newborn infants and their families. Using data from this network, the researchers analyzed variations in outcomes for babies born between 24- and 29-weeks gestation.

The study sample included 38,501 very preterm infants with a median gestational age of 27 weeks. The infants all received care at a U.S. Vermont Oxford Network member hospital in a consolidated health system, where they were born or transferred to within three days of birth. Members of the network tracked all infants, including those who were transferred, until discharge from the initial birth hospitalization or death.

Among the babies in this study, the overall mortality rate was 8.7%. The researchers found that there was a difference of two percentage points in mortality rate between the highest performing systems and the lowest performing systems, with a mortality rate of 9.8% in the lowest performing systems and 7.8% in the highest performing systems. This difference suggests that quality improvement efforts at the system level have the potential to improve patient outcomes for these vulnerable infants.

The researchers also found the average length of stay was 81 days and it ranged from 78 to 90 days at the top and bottom performing systems, respectively.

This has important policy implications because the Medicaid program pays for almost half of all births in the United States each year. Ensuring high quality of care for infants born very preterm is essential as these infants account for a substantial fraction of infant mortality in the United States each year. NICU stays for these infants are also among the most expensive hospitalizations and account for substantial hospital expenditures in the Medicaid program.

“A two-percentage point difference in mortality rate and a 12-day difference in length of stay are significant given the overall mortality rate and length of stay for these patients,” Rogowski said. “These are expensive hospital stays. Results of our study suggest it is possible to increase the survival rate of very preterm babies and also to potentially reduce the resources used in care.”

While the researchers found that there are differences across health systems, questions remain regarding the drivers of this variation. This study was a first step in assessing variation in NICU performance across health systems, Rogowski said.

The study is part of a larger line of research for Rogowski, which is designed to understand and assist all health systems in providing the best quality of care possible. The next step is to determine the drivers behind the variations observed and examine the many factors at play, such as staffing levels or the distribution of resources within hospital systems.

“Our health care system is constantly changing, and we need to continue to look at the implications of these changes, especially for vulnerable populations like these babies,” Rogowski said. “Our goal is to give health systems the necessary information to provide the best care possible, helping these babies have the best possible health trajectory over the life course.”

Additional authors include Lucy Greenberg, statistician at the Vermont Oxford Network (VON); Erika Edwards, research professor at the University of Vermont; Danielle Ehret, the Asfaw Yemiru Green and Gold Professor of Global Health at the University of Vermont; Jeffrey Buzas, professor and director of statistics at the University of Vermont; and Jeffrey Horbar, the Jerold F. Lucey Professor of Neonatal Medicine at the University of Vermont.

Nearly one in every 10 infants in the United States is born preterm, or before 37 weeks of gestational age, according to the Centers for Disease Control and Prevention. Infants born with very low birthweights—under 3.3 pounds at birth—are disproportionately very preterm—29-weeks gestation or earlier. These infants make up 1% of births, but account for more than half of infant deaths in the United States each year. The mortality rate for infants born very preterm, and length of hospital stay, may vary across health systems, according to a new study by researchers at Penn State.

Led by Jeannette Rogowski, professor of health policy and administration at Penn State, the team found that where a very preterm baby is born or receives care immediately after birth can increase or decrease the chance of survival by two percentage points. The findings, which the researchers said demonstrate potential for quality improvement among the nation’s neonatal intensive care units (NICUs) in health systems, were published in JAMA Network Open.

A previous study led by Rogowski found that approximately 84% of very preterm infants are born in a hospital that is part of a consolidated multi-hospital system—a system with two or more hospitals. Among pediatric patients, very preterm infants are the most vulnerable population. However, the variation in the quality of care for very preterm infants across health systems was unknown. This study was the first to address this question, according to Rogowski.

“For the past several decades, research has looked at NICUs in terms of how quality care is provided and how patient outcomes can be optimized,” Rogowski said.

“Not only is the rate of mortality in these babies high, but the rate of morbidity as well. They are at a greater risk of blindness, brain hemorrhages and other serious complications. The care received at birth has the potential to alter the health trajectory of a baby born very preterm, which can have lifetime consequences for the most vulnerable infants.”

Nearly 90% of very low birthweight infants—babies who weigh less than 3.3 pounds and most of whom are born before 37 weeks of gestation—admitted to a NICU in the United States are enrolled in a global network of NICUs, the Vermont Oxford Network, which is dedicated to improving the quality and safety of care for newborn infants and their families. Using data from this network, the researchers analyzed variations in outcomes for babies born between 24- and 29-weeks gestation.

The study sample included 38,501 very preterm infants with a median gestational age of 27 weeks. The infants all received care at a U.S. Vermont Oxford Network member hospital in a consolidated health system, where they were born or transferred to within three days of birth. Members of the network tracked all infants, including those who were transferred, until discharge from the initial birth hospitalization or death.

Among the babies in this study, the overall mortality rate was 8.7%. The researchers found that there was a difference of two percentage points in mortality rate between the highest performing systems and the lowest performing systems, with a mortality rate of 9.8% in the lowest performing systems and 7.8% in the highest performing systems. This difference suggests that quality improvement efforts at the system level have the potential to improve patient outcomes for these vulnerable infants.

The researchers also found the average length of stay was 81 days and it ranged from 78 to 90 days at the top and bottom performing systems, respectively.

This has important policy implications because the Medicaid program pays for almost half of all births in the United States each year. Ensuring high quality of care for infants born very preterm is essential as these infants account for a substantial fraction of infant mortality in the United States each year. NICU stays for these infants are also among the most expensive hospitalizations and account for substantial hospital expenditures in the Medicaid program.

“A two-percentage point difference in mortality rate and a 12-day difference in length of stay are significant given the overall mortality rate and length of stay for these patients,” Rogowski said. “These are expensive hospital stays. Results of our study suggest it is possible to increase the survival rate of very preterm babies and also to potentially reduce the resources used in care.”

While the researchers found that there are differences across health systems, questions remain regarding the drivers of this variation. This study was a first step in assessing variation in NICU performance across health systems, Rogowski said.

The study is part of a larger line of research for Rogowski, which is designed to understand and assist all health systems in providing the best quality of care possible. The next step is to determine the drivers behind the variations observed and examine the many factors at play, such as staffing levels or the distribution of resources within hospital systems.

“Our health care system is constantly changing, and we need to continue to look at the implications of these changes, especially for vulnerable populations like these babies,” Rogowski said. “Our goal is to give health systems the necessary information to provide the best care possible, helping these babies have the best possible health trajectory over the life course.”

Additional authors include Lucy Greenberg, statistician at the Vermont Oxford Network (VON); Erika Edwards, research professor at the University of Vermont; Danielle Ehret, the Asfaw Yemiru Green and Gold Professor of Global Health at the University of Vermont; Jeffrey Buzas, professor and director of statistics at the University of Vermont; and Jeffrey Horbar, the Jerold F. Lucey Professor of Neonatal Medicine at the University of Vermont.