The release of ICD-11 brings new mortality codes for enhanced specificity and breadth of medical statistics and surveillance. The imminent transition to ICD-11 also requires mapping to previous versions of ICD-10 to ensure minimal data loss during the adoption period. The implication of the current study primarily included the identification of unmapped ICD codes when applied to a population-level, “real-world” dataset from Alberta, Canada. We also provided ICD-11 Mortality Tabulation Lists (see Appendix A).
Overall, there was a good translation of ICD-10 to ICD-11 with over 95% of ICD-10 COD codes being mapped to an ICD-11 equivalent. We found two ICD-10 codes that were not mapped in ICD-11 and did not find identifiable codes through manual search. For these two specific codes, it may be related to the introduction of post-coordinated codes in ICD-11. Post coordinated codes is a new feature of ICD-11, which requires information on the sequence of disease from the COD certificate. This allows the provision of multiple values, for the axes of “associated with”, “causing condition”, and “medication,” as examples. For instance, ICD-10 has one code (I13.1) for hypertensive heart and renal disease with renal failure. ICD-11 has specific code BA01 for hypertensive heart disease and BA02 for hypertensive renal disease. Kidney failure was coded as acute (GB60), chronic (GB61) and unspecified (GB6Z). GB60/BA02 is for coding acute kidney failure that is caused by hypertensive renal disease. When acute kidney failure is caused by both hypertensive heart disease and kidney disease, the ICD-11 code is GB60/BA02/BA01.
US CDC developed mortality tabulation lists for three age groups for ICD-10 data. These lists are mainly used for reporting and surveillance causes of death. The US CDC has published two Mortality Tabulation Lists (general mortality, and infant and child mortality) that have categories within most ICD-10 chapters for conditions and external causes. We mapped ICD-11 to the ICD-10 List of 358 Selected COD and the List of 130 Selected Causes of Infant Death, using computational mapping and manual approaches. Our mapping identified two ICD-10 codes that are subdivided into multiple codes in ICD-11. Thus, ICD-10 and ICD-11 tabulation lists are matched well. We reported the top 10 COD in ICD-11 and subdivided malignant neoplasms. The utility of ICD-11 mortality tabulation lists in Alberta data demonstrated feasibility.
Our study has limitations. We do not have a dually coded mortality database. We translated ICD-10 into ICD-11 using WHO mapping and coding tools. Thus, the utility of the ICD-11 mortality tabulation lists is available, but we can not provide validity of these lists. While we have assessed the translation of ICD-10 to ICD-11 in one Canadian provincial dataset, we highly recommend these lists be tested in other datasets.