Patients with hemolytic disease of the fetus and newborn (HDFN) may face delays in advances to treatment because of how differently outcomes are measured and reported in research studies, according to a systematic literature review published recently in the Journal of Perinatalogy.
“This SLR [systematic literature review] shows that there is a considerable variation in the reporting of outcomes across HDFN publications,” stated the authors of this review. They continued, “It highlights the need to standardize the process of outcome selection for all studies within this disease.”
This new review shows that results are often inconsistent, making it harder for doctors and scientists to compare studies and use the information to guide patient care.
The review analyzed 2,412 studies published between 2005 and 2023, of which 238 met the inclusion criteria. Among them, 221 were observational and 17 were clinical trials. Across these, 104 unique outcomes were reported, covering maternal, obstetric, neonatal, long-term, and patient-reported measures. However, the definitions of those outcomes were highly variable, especially for important indicators such as total serum bilirubin, which is used to track the severity of disease in newborns.
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For families, this means that progress toward better and safer treatment options could be slowed. For example, 46 percent of studies reported on exchange transfusions in newborns, but the way results were described, such as the age of first transfusion or the number of procedures, differed widely. Similarly, fetal mortality was reported in 12 percent of studies, yet definitions of loss ranged from “perinatal mortality” to “fetal death,” leaving uncertainty in how to compare outcomes across different reports.
Long-term outcomes were less frequently studied, with only 12 percent of research reporting effects beyond the neonatal stage. Of those, neurological or cognitive issues were most common. Behavioral problems, need for long-term support, and ongoing mortality were also noted but in fewer studies. This leaves many unanswered questions for parents and clinicians trying to understand what the future may hold for children affected by HDFN.
Patient-reported outcomes were rarely included, showing up in less than 1 percent of studies. This gap limits the understanding of how treatments and disease affect quality of life for mothers and families. Even maternal outcomes, such as a history of previous pregnancy complications, were reported in only 4 percent of studies.
The authors conclude that standardizing how outcomes are defined and reported could help doctors and families alike. For patients, this may mean faster progress in identifying the most effective therapies, clearer understanding of treatment risks, and stronger evidence to guide pregnancy and newborn care in HDFN.
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