Reconstructing Long-Term Coherent Cause-of-Death Series, a Necessary Step for Analyzing Trends

Every time the classification of causes of death is changed, time series of deaths by cause are disrupted in more or less profound ways. When changes involve only the merging of several items or splitting a single item into several new categories, the problems caused by these ruptures are not too difficult to solve. A more or less severe imbroglio occurs, however, each time a new item results from recombining portions of different split items. Sometimes, but very rarely, some countries proceed to a bridge coding during the year of transition, which can help reconstruct coherent time series. This article first summarizes the general principles of the method developed for France by Meslé and Vallin to reconstruct complete series for France from 1925 to 1999 in the detailed list of the 9th WHO International Classification of Diseases (ICD), doing so by successively bridging a posteriori the five versions of the ICD that were in use during that period. Second, it reports on several methodological improvements that have been developed with the aim to reconstruct and analyze mortality trends by cause in sixteen industrialized countries.