Cohort Definition Name : All events of Hemolytic Disease Fetus and Newborn (HDFN), RhD type, with a pregnancy episode
Contributor name : Joel Swerdel’
Contributor OrcId : 0000-0002-6976-2594’
Logic Description : All events of Hemolytic Disease Fetus and Newborn (HDFN) indexed on diagnosis date, requiring a pregnancy episode that started any time prior index and pregnancy ends between 14 days pre to all time post index patients exit the cohort 270 days post index or on events signaling pregnancy end. Reoccurrence events are collapsed if the next event starts within 90 days of end of prior event.
Recommended study application : target
Assertion statement : This cohort definition was executed on at least one real person-level observational health data source and resulted in a cohort with at least 1 person.
Target Clinical Description : Hemolytic disease of the fetus and newborn (HDFN), also known as alloimmune HDFN or erythroblastosis fetalis, is caused by the destruction of red blood cells (RBCs) of the neonate or fetus by maternal immunoglobulin G (IgG) antibodies. These antibodies are produced when fetal erythrocytes, which express an RBC antigen not expressed in the mother, gain access to the maternal circulation. Presentation: Mild to moderate disease — Less severely affected infants typically present with self-limited hemolytic disease, manifested as hyperbilirubinemia within the first 24 hours of life. They may also have symptomatic anemia (eg, lethargy or tachycardia) but without signs of circulatory collapse. Infants with Rhesus (Rh) can present with symptomatic anemia that requires red blood cell (RBC) transfusion. Hydrops fetalis — Infants with severe life-threatening anemia (eg, hydrops fetalis) present with skin edema, pleural or pericardial effusion, or ascites. Infants with RhD and some minor blood group incompatibilities, such as Kell, are at risk for hydrops fetalis, especially pregnancies without antenatal care.
Evaluation conclusion : We developed a prevalent cohort definition for HDFN using a concept set of 3 concepts which incorporated all those found from the literature review, the analysis of PHOEBE, and orphan concepts in cohort diagnostics. The algorithm retrieves subjects from 5 databases tested. There was no evidence for the need to consider index date reclassification. We developed a more specific cohort requiring a second diagnosis or observation code for HDFN in the time period 31-365 days after index. This cohort improves the specificity of the algorithm albeit at the expense of sensitivity as determined by PheValuator. The significant loss in sensitivity, however, precludes its use for our analytical use case. The selected algorithm uses the pregnancy algorithm with the definition. This will limit its use to within data partners that use the pregnancy algorithm; the coding for isoimmunization may occur outside of a pregnancy episode, e.g., post-partum finding, which would not produce useful subjects for study.
Imported to the OHDSI Phenotype Library. It may be expected to be found with id = 1019 in the next release. Thank you