In this video, we are going to briefly overview the history of the international classification system. We're going to see the first signs of the recognition for the need of mortality statistic and causes of diseases in the 17th century and how the system has been adapted from the World Health Organization. We're also going to discuss how the international classification system of diseases has evolved over the period of almost two centuries. We're going to see how it evolved to include mortality and morbidity data, as well as both etiology and manifestation of diseases. Finally, the latest version of ICT 11 codes have been specifically designed for a digital era. The first effort to systematically classify diseases goes back in the 17th century. John Graunt, who was an epidemiologist and statistician, was looking into the death of children who're born alive, but died before the age of six. He recognized the need to organize mortality data into some logical form and therefore develop the first statistical study of disease called the London Bills of Mortality. Here we see an example of this effort. The weekly Bill of Mortality was a single sheet of paper that listed on one side, the mortality figures for each of the 130 parishes of London, and on the other, the various causes of death. The resulting classifications were consider to be of little utility due to poor statistical data and inconsistencies in nomenclature. William Farr is considered as the first medical statistician of the general Register Office of England and Wales. He submitted his report on Nomenclature and Statistical Classification of Diseases in 1855. In this report, he included most of those fatal diseases that affect health. In fact, in mid 80s, it was recognized the need of classification of diseases that was uniform and internationally accepted. Farr pointed out that medicine has progressed by that time and many diseases could affect particular organs, pointing out for a classification of diseases related to the organic systems they affect. He also considered previous classifications as largely symptomatic and the arrangements could not be used for statistical analysis. The beginning of modern classification can be considered as the 1893. The chief of statistical services of Paris prepared a classification based on the principle of distinguishing between general diseases and those localized to a particular organ or anatomical site. Bertillon presented his report on causes of death and incapacity for work, including hospital admissions. Bertillon's main headings included general diseases, diseases of nervous systems and sense organs, circulatory system, respiratory system, digestive system, and many others. The International Statistical Institute adapted the first edition of international classification system, the so-called the Internationally List of Causes of Death in 1893. In 1899, the classification system was adopted by some American and European countries. It was also decided that the classification system should be updated approximately every 10 years. The second edition of the International Classification System that took place in '99, involved in renaming the system to International Classification of Causes of Sickness and Death. In 1920, the new edition involved some disease categorization refinement, as well as adding few extra diseases. The fourth edition of the classification of diseases in 1929 recognized that it should move the definition of classification of diseases from organs and systems to a classification based on the etiology. It was also recognized that this change couldn't happen immediately, but it should have taken place progressively. In fifth revision that took place in 1938, some changes were made for scientific reasons. It was also decided for practical consideration to look into compatibility between versions 4 and 5. In this way, the fifth revision became a model for subsequent revisions. In 1948, the sixth revision of the International Classification of Diseases System was adopted by the World Health Organization as its International Classification of Diseases, injuries, and causes of death. It was also recognized the need to extend the same coding system to diseases that are not fatal, but they cause disability. It was the first time that along with the classification of mortality, it was included a classification of morbidity. Morbidity relates to suffering from a disease or medical condition which is chronic. A new main category was also added, which included mental, psychoneurotic, and personality disorders. The seventh revision conference was held in Paris in 1955, and the revision was limited to essential changes. In the eighth revision, there were not any major structure changes. However, a fourth digit subdivision has been added to show the association between hypertension and cerebrovascular diseases and ischemic heart disease. Also in infectious diseases, a fourth digit subdivision was added to provide the various clinical manifestations. By the ninth revision of the International Classification System' there was an enormous interest in it worldwide. As we're going to see later, ICD-9 is also the coding adopted in MIMIC-3 database. A major change was the adoption of a [inaudible] classification that reflected manifestation in etiology respectively. Since ICD codes is a classification system based on etiology, it was proposed that another coding should reflect manifestation. These two codes are distinguished by symbols of a dagger or an asterisk. The ICD-10 coding system was endorsed by the 43rd World Health Assembly in May 1990. It came into use in World Health Organization member states as from 1994. ICD-10 involved a thorough rethinking of its structure and an effort to devise a stable and flexible classification which won't require fundamental changes. Also, the structure of codes have changed from numeric to alphanumeric, which allows for significant expansion. Another point that it was made during the ICD-10 introduction was that a 10 years interval was too short because revisions were starting before thoroughly evaluating the system. Up to present, the ICD-10 is the coding system most commonly used in hospitals and national databases. The ICD-11 coding has been adopted by the 72nd World Health Assembly in 2019, and it comes into effect in January 2022. ICD-11 has been designed for digital use and it's fully electronic. It aims to assist implementation and reduce error in diagnosis while it makes it more adaptable in local countries. The system has an improved ability to code for the quality and safety of health care and highlights socioeconomic factors that directly and indirectly contribute to people's health. Finally, it also tries to simplify diagnostic descriptions, particularly in relation to mental health. Summarizing, the need to organize disease data systematically was recognized in the 17th century. However, it wasn't until the late 80s where the first international list of causes of death was founded. ICD codes are ubiquitously used in medicine and they are necessary to be able to compare statistics across different countries and across different times.
