Comparing Causes of Death between Years - Accounting for the Change from ICD-9 to ICD-10

The International Classification of Diseases (ICD) is a system designed to promote international comparability in the classification of disease, including reporting causes of death on the death certificate. Titles for each cause of death and the exact diseases included in each cause are revised periodically in order to incorporate advances in medical knowledge. The latest change in ICD codes was implemented for deaths that occurred in 1999 and thereafter.

ICD revisions can create breaks in the comparability of trend data for some causes of death, when classification and coding changes move a disease or condition from one category to another. The comparability ratio for a given cause of death is a measure of the net effect of a new ICD revision on the number of deaths attributed to that cause.

The table accessible below lists the ICD-10/IDC-9 comparability ratios for 113 selected causes of death. These ratios provide a way to account for the effects of coding and classification changes from ICD-9 to ICD-10, so that deaths from specific causes can be compared across years. For each cause of death, the table also shows:

  • Actual data for 1999 (number of deaths coded using ICD-10),

  • Actual data for 1998 (number of deaths coded using ICD-9), and

  • Comparability-modified data for 1998 (number of deaths in 1998 modified by applying the comparability ratio).

Access the Table (PDF,  45 KB)

Last Revised: January 12, 2015