Background: Different countries have conducted comparability studies between Revisions 10 and 9 of the International Classification of Diseases for aggregate lists of causes of death. In Spain, the COMPARA project was aimed at evaluating the impact of the revision change.
Methods: Descriptive cross-sectional epidemiological study of 88,048 deaths recorded in Spain in 1999 with the underlying cause of death doubled coded in ICD-9 and ICD-10. The theoretical correspondences between the ICD on the lists of the National Institute of Statistics and Murcia are established. The comparability rates and their confidence intervals, and the total kappa index were calculated.
Results: A decline in infectious diseases (-1.7%) and viral hepatitis, (-12.3%) declined under Tenth revision, while AIDS showed an increase (5.7%). Neoplasms increased a little (0.3%) with the inclusion of the Mielodisplasic Syndrome (55.2%). Diabetes mellitus is increased (2.1%). Mental disorders declined on dementia being shifted to Alzheimer's disease (28.6%). Cardiovascular diseases dropped slightly (-1.4%), without any impact on cerebrovascular diseases, although acute myocardial infarct decreased (-0.6%) while ischemic heart disease increased (0.3%). Pneumonia decreased (-12.5%) and hepatic cirrhosis grows (4.3%). Ill-defined conditions increased due to cardiorespiratory insufficiencies. The external causes show no change without including the accuracy of ICD-9. The National Institute of Statistics 102 groups list obtained a total kappa index of 95.4%, similar to the Murcia variants.
Conclusions: Although ICD-10 has a lesser overall impact, the significant comparability rates of the causes of death groups between the revisions with important absolute differences should be taken into account.