Validity of Congenital Malformation Diagnoses in Healthcare Claims from a University Hospital in Japan.

PURPOSE This study aimed to assess the validity of diagnoses of congenital malformations (CMs) recorded in claims of a university hospital in Japan. METHODS Congenital malformations were identified according to Code Q00-Q89 of the International Classification of Diseases, 10th revision. All the children who had been diagnosed with CMs based on their claims in 2015 and within 1 year from their birth month were selected for this study. The infants' medical records were considered as a gold standard. Positive predictive values (PPVs) for CMs were calculated. RESULTS This study included 227 infants who had a CM diagnosis in their claims. Based on the algorithms established by the Quebec Pregnancy Cohort study group, the PPV for any CM was 90.7% and that for major CMs (MCMs) was 91.5%. Concerning MCMs of specific organ systems, those of the circulatory system (PPV 85.1%) were the most frequent, followed by cleft lip and cleft palate (PPV 100.0%), and other CMs of the digestive system (PPV 96.4%). Based on the EUROCAT classification, the PPV for any MCM was 88.5%. Specific MCMs reported in ≥ 20 infants were ventricular septal defect (PPV 96.0%), patent ductus arteriosus (PPV 72.7%) and cleft lip with or without cleft palate (PPV 100.0%). CONCLUSIONS The PPVs for CMs in the Japanese administrative data were high enough to suggest that these data could be utilized for perinatal pharmacoepidemiological evaluations. The results were from a single center, and further validation studies are needed.