Dealing with statistical ruptures related to the implementation of ICD10. Case of West Germany and Czech Republic.

Marketa Pechholdova, Charles University

Everyone interested in the long-term series of mortality by cause of death will, sooner or later, face the challenge of bridging statistical discontinuities related to the implementations of the WHO International Classification of Diseases (ICD) new revisions. Long-term continuous time series of mortality by cause of death are already available for a considerable number of countries (e.g. France, West Germany, Czech Republic, Russia and some ex-Soviet countries, UK and Netherlands). Nevertheless, all of them end at the moment of the implementation of ICD10, which probably represents the largest qualitative and quantitative change to cause-of-death statistics in over 50 years. ICD10 came into effect in 1993. The Czech Republic was among the first countries to adopt it (in 1994), Germany joined in 1998. Previously we have reconstructed the cause-of-death time series for both countries as from 1968 (thus covering the periods of ICD8 and ICD9) at the 3-digit ICD9 level. Using these data in the current project, we updated the existing time series to the ICD10 structure and examined the differential effect of the ICD10 introduction on the statistical continuity in the two countries of interest. We point at the difficulties of the ICD10 and show how we proceeded in the concrete cases.