Newborn Transfer May Not Reflect True Rate of Complications

Tara Haelle

February 12, 2020

Neonatal transfer was the factor most often associated with unexpected, severe complications at birth, particularly at hospitals that had the highest rates of complications, according to a cross-sectional study published online February 12 in JAMA Network Open.

"Transfers were more likely to be necessary when infants were born in hospitals with lower levels of neonatal care," Mark A. Clapp, MD, MPH, of Massachusetts General Hospital in Boston, and colleagues write. "Thus, if this metric is to be used in its current form, it would appear that accreditors, regulatory bodies, and payers should consider adjusting for or stratifying by a hospital's level of neonatal care to avoid disincentivizing against appropriate transfers."

The Joint Commission recently included unexpected complications in term newborns as a marker of quality of obstetric care, but it does not currently recommend any risk adjustment for the metric. The authors aimed to learn which factors regarding patients and hospitals were associated with such complications. Severe, unexpected newborn complications include death, seizure, use of assisted ventilation for at least 6 hours, transfer to another facility, or a 5-minute Apgar score of 3 or less.

"This measure has been proposed to serve as a balancing measure to maternal metrics, such as the rate of nulliparous, term, singleton, vertex-presenting cesarean deliveries," the authors explain.

The study's findings "highlight the challenges in developing obstetric quality metrics," David B. Nelson, MD, and Catherine Y. Spong, MD, of the University of Texas Southwestern Medical Center in Dallas, write in an invited commentary.

Valid indicators "should reflect not just an adverse event but also an event that could occur less often with improvements in clinical care" without leading to "unintended adverse consequences," they continue.

"Unexpected newborn complication rates — measured in part by neonatal transfers — fail both of these principles," Nelson and Spong explain. "It is intuitive that lower-level neonatal care facilities would have higher rates of neonatal transfer" and are therefore inadvertently penalized, given how "neonatal transfers dominate the composite," they write.

Hospital, Mother, and Delivery Characteristics Examined

For their study, the researchers used county-level birth certificate data from the National Center for Health Statistics and included all live-born, term, singleton newborns weighing at least 2500 grams who were born from January 2015 to December 2017 in US counties that had exactly one obstetric hospital (to ensure that all births in the county were attributed only to that hospital).

After excluding deliveries outside of obstetric facilities, the total sample included 1,754,852 births from 576 hospitals. All of the hospitals performed at least 300 deliveries a year. Hospital data came from the 2015 American Hospital Association annual survey and primarily provided the number of hospitals with obstetric-only beds and neonatal intensive care units (NICUs).

Among mothers, the researchers compared age, race, ethnicity, birthplace, educational level, insurance payer, parity, and the following comorbidities: tobacco use, pregestational diabetes, gestational diabetes, chronic hypertension, and pregnancy-related hypertension. The following child and delivery factors were compared: infant gestational age and birth weight, delivery mode, maternal transfer, and whether labor was by induction or was spontaneous.

In addition to complication rates, four hospital characteristics were considered: the proportion of births covered by Medicaid, the average delivery volume per year, the percentage of rural population in the county, and the level of neonatal care available. The level of care was considered high if the hospital had an NICU; it was considered low if the hospital did not have an NICU.

Neonatal Transfers Lead Severe Complications

The average rate of complications was 15.3 per 1000 births, but the range varied greatly by hospital, from 0.6 to 89.9 per 1000 births.

High complication rates occurred more often in hospitals in which the mothers were more frequently younger, white, less educated, publicly insured, and were admitted with more medical comorbidities. However, when the researchers adjusted for these differences, case mix appeared to account for only 11.3% of variation in complication rates between counties. "When observed county and hospital factors were added, the variation was slightly reduced to 8.8%," the authors report.

The foremost factor linked to complication rates was neonatal transfer, which accounted for 66% of all complications in hospitals with high transfer rates and 41.2% of all complications in hospitals with low transfer rates. Excluding transfer, the average rate of complications was 5.1 per 1000 births.

Hospital delivery volume and rural population percentage had no impact on complication rates. The proportion of Medicaid-covered deliveries was not significantly related, but the level of neonatal care did matter. Newborns born in hospitals without an NICU, which had a complication rate of 18.6 per 1000 births, had 55% higher odds of complications than infants born in hospitals with an NICU, for which the average rate was 10.1 (P < .001 for rates; adjusted odds ratio [aOR], 1.55).

When the researchers excluded transfers as complications, rates of complication were similar — 5.1 per 1000 births in hospitals without an NICU, and 4.8 in hospitals with an NICU.

The maternal factor most associated with complications was comorbidities. Compared to risk among mothers who did not have comorbidities, risk for complications was tripled for mothers with pregestational diabetes (aOR, 2.97) and was increased for mothers with gestational diabetes (aOR, 1.36), chronic hypertension (aOR, 1.47), and pregnancy-induced hypertension (aOR, 1.51).

Further, newborns' complication rates were higher among mothers who had comorbidities in hospitals that did not have an NICU. Again, after removing transfers as a complication, the numbers evened out, and the complication rates were similar between hospitals that had an NICU and those that did not.

"This serves as a caution to not throw the baby out with the bathwater, given that the unintended consequences of disincentivizing necessary neonatal transfers to higher levels of care are obvious," the commentators write.

"Better measures of obstetric quality are needed — especially when examining outcome (ie, performance) measures. Indeed, some outcomes may be too infrequent to draw meaningful conclusions or comparisons of quality," they add. They note that complication rates excluding transfers occur in less than 1% of term deliveries.

They also point out that bias and potential unintended consequences against rural areas could occur if this new complication rate metric were to be used.

"Comparing isolated birthing facilities in a county skews the hospital comparison to counties in less-populated (ie, rural) regions," they warn. "Suggesting that lower-level neonatal care facilities perform poorly simply because of appropriate transfers to higher levels of care may accelerate the already declining access to care in rural areas."

Hospitals with obstetric services dropped from 55% to 46% in rural counties from 2004 to 2014, "leaving women in many areas of the United States without local access to basic obstetric care," they note. "More frightening, what if hospitals defer necessary transfers to avoid such labels?"

The research was funded by the Society for Maternal-Fetal Medicine. The study authors and editorialists have disclosed no relevant financial relationships.

JAMA Netw Open. Published online February 12, 2020. Full text, Editorial

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