Celiac.com 01/19/2017 - A team of researchers recently set out to validate the celiac disease diagnoses recorded in the Danish National Patient Register.
They are variously affiliated with the Hans Christian Andersen Children’s Hospital, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Odense, Denmark; Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Department of Pediatrics, Ostfold Hospital Trust, Fredrikstad, Norway; Department of Pathology, Hvidovre Hospital, Department of Public Health, University of Copenhagen, Copenhagen, Denmark; Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA; Department of Clinical Immunology, Odense University Hospital, Odense, Denmark.
To validate the diagnoses, they used information on duodenal biopsies from a national register of pathology reports (the Patobank) and information on celiac disease-specific antibodies and human leukocyte antigen (HLA) genotypes obtained from patient medical records. Their study included all children born from 1995 to 2012 and registered as having celiac disease in the Danish National Patient Register.
They reviewed all pathology reports on duodenal biopsies in the Patobank, along with medical record information on celiac disease-specific antibodies, such as anti-tissue transglutaminase 2 IgA and IgG, endomysial antibodies IgA, and anti-deamidated gliadin peptide IgG) and HLA genotypes.
In the Danish National Patient Register, they found 2,247 children with celiac disease. Duodenal biopsies for 1,555 of the children (69%) were registered in the Patobank; 1,127 (50%) had biopsies consistent with celiac disease; i.e., Marsh 2–3.
The team accessed the medical records of 95% of the children registered in the Danish National Patient Register with celiac disease. They found that 1,510 patients, or 67%, had one or more positive antibody-test results; 1,120, or 50% had anti-tissue transglutaminase 2 IgA ten times or more above the upper limit of the normal range and/or positive endomysial antibody results.
The positive predictive value depended on the criteria used for validation and the types and numbers of registrations included in the analysis. Accordingly, the values ranged from 62% (95% confidence interval: 60%–64%) to 86% (95% confidence interval: 84%–87%).
These findings indicate that the Danish National Patient Register is a valuable source to identify patients who have been diagnosed with celiac disease. However, they recommend that researchers validate and document diagnoses before using patient data for research purposes.