Birth Hospital ZIP Code and Neonatal Outcomes in Very Preterm Birth
January 1, 2022
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By Ellen Feldman, MD
Altru Health System, Grand Forks, ND
SUMMARY POINTS
- This retrospective chart review of 6,461 very preterm birth (VPTB) infants (born before 32 weeks’ gestation) incorporated data from 39 New York City hospitals and examined demographic and outcome data.
- VPTB infants born to families from predominately Black neighborhoods had 1.6 times the risk of neonatal morbidity and mortality than infants born to families from predominately White neighborhoods. The delivery hospital was responsible for 63% (P < 0.001) of this difference.
SYNOPSIS: This retrospective chart review examined demographic information and outcomes of infants born earlier than 32 weeks’ gestation. Findings indicate infants of mothers who live in neighborhoods with predominately Black residents have a higher morbidity and mortality than infants of mothers living in predominately White neighborhoods. The findings also indicate that the choice of delivery hospital is responsible for more than 50% of this difference.
SOURCE: Janevic T, Zeitlin J, Egorova NN, et al. Racial and economic neighborhood segregation, site of delivery, morbidity and mortality in neonates born very preterm. J Pediatr 2021;235:116-123.
In 1920, the mortality rate for Black infants in the United States was 43% higher than for White infants. One hundred years later, despite a decline in infant mortality rates overall, the mortality rates for Black infants in the United States is a staggering 122% higher than for White infants.1,2
Studies have looked at multiple factors affecting these findings, including genetic, socioeconomic, psychological, and environmental influences.2 Janevic et al noted that racial residential segregation is one recognized contributor to higher infant mortality rates among Black infants and that there also is an association of racial residential segregation with very preterm birth (VPTB), defined as children born earlier than 32 weeks of gestation. Janevic et al additionally noted that economic segregation often is closely tied to racial residential segregation, although the two may deviate in essential components.
VPTB children are at a high risk of mortality. If an infant with VPTB survives the neonatal period, there is a likelihood of morbidity, with the potential for neurodevelopmental consequences and lifelong disability.3
Taking all these factors into consideration, the goals of this retrospective chart review using birth certificates and discharge data (2010-2014) from New York City hospitals was to determine:
- any association between racial and economic segregation of the mother’s neighborhood and very preterm mortality and morbidity;
- the role the delivery hospital plays in differences between very preterm morbidity and mortality according to the mothers’ neighborhood;
- assess if racial or economic segregation of the hospital affects the association between the mother’s neighborhood and very preterm morbidity and mortality.
A cohort of 6,461 infants born in 39 hospitals was identified for the study, including infants born from 24 to 31 weeks of gestation and excluding infants with congenital abnormalities and/or mothers not living in New York City.
To measure racial and economic segregation, the index of concentration at the extremes (ICE) was employed.4 ICE measures relative population concentrations: in this study, ICE Race reflected the amount of urban space inhabited by Black residents relative to White residents, ICE Income measured poor households (earning < $25,000 annually) relative to wealthy (earning > $100,000 annually), while ICE Race-Income combined these two. The results were divided into quintiles (Q1 to Q5), where ICE Race Q1 represented ZIP codes or neighborhoods with the highest concentration of Black relative to White residents, ICE Income Q1 contained neighborhoods with the highest percentage of poor relative to wealthy residents, and ICE Race-Income Q1 represented ZIP codes with the highest proportion of Black, low-income residents relative to ZIP codes populated by White, high-income residents.
RESULTS
The overall risk of neonatal mortality and morbidity in the study participants was 28%. VPTB infants of families from Q1 ICE Race neighborhoods had 1.6 times higher risk for neonatal morbidity and mortality than the families in Q5 (95% confidence interval [CI], 1.2-2.1). The risk for VPTB mortality and morbidity was similarly higher in ICE Q1 Income and in ICE Race-Income combined. (See Table 1.)
Table 1. Percent and Risk of Neonatal Morbidity or Mortality According to Economic and Racial Segregation Among VPTB Infants | |||
|
|
Q1 % Neonatal Morbidity and Mortality |
Q5 % Neonatal Morbidity and Mortality |
Relative Risk for Q1 |
|
ICE Race |
n = 2,216; 33.2% (736 infants) |
n = 563; 20.8% (117 infants) |
1.6 (95% CI, 1.2-2.1) |
|
ICE Income |
n = 2,506; 31.2% (782 infants) |
n = 522; 22.0% (115 infants) |
1.4 (95% CI, 1.1-1.9) |
|
ICE Race-Income |
n = 2,554; 34.0% (869 infants) |
n = 548; 21.4% (117 infants) |
1.59 (95% CI, 1.2-2.2) |
|
VPTB: very preterm birth; ICE: index of concentration at the extremes; CI: confidence interval | |||
Notably, one-third of VPTB infants were from the Q1 Race category, with a total of 2,216 infants out of the total 6,461 in this quintile, compared to 563 infants falling into the Q5 Race quintile.
Subjecting these numbers to extensive analysis and adjusting for case-mix severity revealed that the delivery hospital accounted for 63% of the difference in VPTB mortality and morbidity when looking at ICE-Race Q1 vs. Q2-Q5, 61% when looking at ICE-Income, and 57% when looking at ICE-Race-Income. These were statistically significant, with P values of < 0.001 for ICE-Race and ICE Race-Income results and P = 0.006 for ICE-income. Patient factors, such as maternal education, insurance, health conditions and gestational age, all contributed to this difference as well.
Additional statistical analysis compared infants from Q1 Race neighborhoods delivered in hospitals with a greater relative concentration of White residents. These infants showed a decrease in risk of neonatal morbidity and mortality from 38% (when delivered in neighborhood hospitals with a higher concentration of Black residents) to 25% (P = 0.045), even after adjusting for severity of patient-case mix. However, no significant results were noted in this area when looking at ICE Income or ICE Race-income quintiles.
COMMENTARY
This large-scale chart review looking at a cohort of 6,461 VPTB infants born in any one of 39 hospitals in New York City reveals a 1.6 times higher rate of neonatal morbidity and mortality for infants with mothers living in predominately Black neighborhoods when compared to infants with mothers living in predominately White neighborhoods. Additionally, the risk of neonatal morbidity and mortality (even when adjusted for severity of patient case-mix) in this cohort dropped from 38% to 25% when the delivery hospital changed from one located in a predominantly Black to a predominately White neighborhood.
The finding that the ZIP code of the hospital where a child is born has significant effect on neonatal morbidity and mortality in VPTB not only is a societal problem, but it also represents a medical and public health issue. There are no conclusions from this study regarding the mechanism by which this imbalance occurs; future investigations are needed to develop a full understanding.
However, immediate interventions can be considered for this high-risk group, including addressing social determinants of health during neonatal intensive care unit stay and the postnatal period and prioritizing hospital- and city-level policies that attempt to equalize scarce healthcare resources.
This work shines a light on societal factors interwoven into the fabric of the healthcare system in New York City. While generalization of these results is not possible due to the geographic limitations of this study, there are reasons to suspect that the patterns of racial and economic segregation noted here are reflected in other cities nationwide and may result in similar levels of healthcare inequity.
Structural racism refers to policies in a society that contribute to and support an unfair advantage to some people while disadvantaging another group based on race.5 Although it can be argued that there are no written policies dictating where people in New York City live according to race, the existence of racial and economic segregation in many U.S. cities and towns is not arguable and appears to be supported by a complex interweaving of multiple societal factors (most of which are well beyond the scope of this article).
At the least, this work may serve as a reminder to the healthcare provider of the importance of developing a complete and nuanced understanding of a patient and recognizing that environment often affects healthcare risk factors and wellness efforts.
Additionally, the results of this study may motivate a provider to consider a discussion with a patient about how to choose a delivery hospital, although, in many situations, factors such as insurance may dictate that choice.
Many of us entered healthcare with the hope of delivering care and improving lives with newly acquired knowledge and techniques. This work by Janevic et al reminds us that all our knowledge and cutting-edge equipment may fall short compared to barriers surrounding equitable access to care. Advocating for a nationwide (or even international) equalization of healthcare quality (reflected in outcome data) may be considered an integral component of delivering health and wellness.
REFERENCES
- Singh GK, Yu SM. Infant mortality in the United States, 1915-2017: Large social inequalities have persisted for over a century. Int J MCH AIDS 2019;8:19-31.
- Artiga S, Pham O, Orgera K, Ranji U. Racial disparities in maternal and infant health: An overview. KFF. Published Nov. 10, 2020. https://www.kff.org/report-section/racial-disparities-in-maternal-and-infant-health-an-overview-issue-brief/
- Centers for Disease Control and Prevention. Picture of America: Reproductive outcomes. https://www.cdc.gov/pictureofamerica/pdfs/picture_of_america_reproductive_outcomes.pdf
- Chambers BD, Baer RJ, McLemore MR, Jelliffe-Pawlowski LL. Using index of concentration at the extremes as indicators of structural racism to evaluate the association with preterm birth and infant mortality-California, 2011-2012. J Urban Health 2019;96:159-170.
- Bailey ZD, Feldman JM, Bassett MT. How structural racism works — Racist policies as a root cause of U.S. racial health inequities. N Engl J Med 2021;384:768-773.
This work may serve as a reminder to the healthcare provider of the importance of developing a complete and nuanced understanding of a patient and recognizing that environment often affects healthcare risk factors and wellness efforts.
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