[Comparison of registration of data from the Danish Childhood Diabetes Register and The National Discharge Register].

In 1996 The Danish Childhood Diabetes Register (DIA-REG B&U) was established. Data are validated yearly against The National Discharge Register (NDR). In the first seven years, 1509 cases were found either in the DSBD or in the NDR. Four percent did not have diabetes. Two percent had another code than DE10. In 5.2% cases, the first registration dates in NDR were a half year or more after onset of diabetes. In addition, there were 29 cases only found in the DSBD. In conclusion, the sensitivity and specificity is high in the NDR, but there is some misclassification and the first admission dates are not equal to the date of disease onset. Thus, studies of diabetes in childhood should be based on a validated register such as the DIA-REG B&U.