JMIR Publications

ABSTRACT

Background:

Hemolytic disease of the fetus and newborn (HDFN) is a rare disease caused by maternal-fetal red blood cell antigen incompatibility. Maternal immunoglobulin G antibodies destroy the fetal or neonate red blood cells, leading to hemolysis, hyperbilirubinemia, and anemia. Although routine screening and alloimmunization prevention programs have contributed to the decline in HDFN in the United States, further understanding of its epidemiology is still needed.

Objective:

We aim to provide an overview of the study design, methodology, and analytical approach used to investigate the epidemiology, treatment, and healthcare resource utilization of HDFN within a large integrated healthcare system.

Methods:

We conducted a retrospective cohort study of pregnant patients who received obstetrical care within Kaiser Permanente Southern California (KPSC) healthcare system from January 1, 2008, to June 30, 2022. To identify HDFN cases, we used a novel methodology developed by KPSC researchers combining structured data and detailed clinical information from unstructured records via a Natural Language Processing (NLP)–assisted chart review process. Chi-square and Wilcoxon rank-sum tests were used to compare the distribution of maternal and infant demographic characteristics, and medical and perinatal conditions by HDFN status. We also evaluated the association between HDFN and adverse perinatal outcomes using logistics regression models. Planned analyses utilizing this unique cohort will include describing the annual prevalence, healthcare resource utilization, and treatment patterns of mothers and infants by HDFN status.

Results:

The study population consisted of 464,711 pregnancies, of which 136 were HDFN cases confirmed by chart review and resulted in 138 births (137 live births, 1 stillbirth). The mean age at pregnancy was 29.8 years (standard deviation: 5.7), and the population was racially and ethnically diverse. HDFN cases were more likely to be older (P=.0030), from a non-Hispanic White racial/ethnic group (P=.0121), with Medicaid or private insurance coverage (P=.0351), multipara (P<.0001), multigravida (P<.0001), to have a preterm (P<.0001) and low birthweight infant (P=.0003), and have a history of renal disease (P=.0003).

Conclusions:

We present an overview of the methodology developed by KPSC clinicians and researchers on the epidemiology, treatment, and healthcare resource utilization of HDFN within a large and demographically diverse population of pregnant patients. Our novel methodology, combining both structured and unstructured data and an NLP-assisted chart review process ensured the successful identification of true cases to carry out pharmaco-epidemiological studies.