ICD codes

The International Classification of Diseases (ICD), maintained by the World Health Organisation (WHO), is the international standard diagnostic classification. It is used for classifying both morbidity and mortality. The ICD is currently on its tenth revision (ICD-10); as advances in diagnoses occur and opinions change, it is periodically totally revised. The period covered by this atlas (1981 to 2004) spans two versions of the ICD, 9 and 10. A brief history of the classification can be found on the WHO website (www.who.int/classifications/icd/en/HistoryOfICD.pdf).

Additionally, updates within a revision can also be made. For example, there was originally no coding for MRSA (Methicillin-resistant Staphylococcus aureus) in ICD-10. However, as the incidence of MRSA has increased so much in recent years the WHO has added codes to identify it; however, this update was not applied until after the period that this atlas covers. Atlases of mortality usually map prevalent diseases defined according to contemporary medical categorisation.