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The Role of the ICD-10 in Epidemiology

The International Classification of Diseases (ICD) is the standard diagnostic tool for epidemiology, health management, and clinical purposes.1 Published by the World Health Organization (WHO), it is used worldwide to analyze the general health situation of various population groups.1 The ICD is revised periodically and is currently in its 10th edition.2 The ICD-10 was endorsed in May 1990 by the 43rd World Health Assembly and officially published in 1992.1 It has now been cited in more than 20,000 scientific articles and used by more than 100 countries around the world.1

The ICD-10 provides a system of diagnostic codes for classifying diseases, disorders, injuries, and other related health conditions.1 Roughly 70,000 different codes in the ICD-10 function as the foundation for the identification of health trends and statistics on an international level.2 Other uses of the ICD-10 include monitoring morbidity and mortality statistics, investigating the incidence and prevalence of disease, observing reimbursements and resource allocation trends, and keeping track of safety and quality guidelines.1 The ICD-10 lists health conditions in a hierarchical fashion that allows for easy navigation of health information, assessment of health data between regions, and data comparisons in the same location across different time periods.1  

The classifications of disease and other health conditions in the ICD-10 have provided universal criteria that facilitate epidemiological studies.3 By definition, epidemiology is the scientific study of the distribution and determinants of health-related states and events in specified populations.4 The role of the ICD-10 in epidemiology has most frequently been to provide a standardized means of diagnosing disease or related health conditions.1 One example is a recent study completed by researchers in South Korea that aimed to evaluate the epidemiology and risk factors of coccyx fracture.5 The researchers identified coccyx fractures, which occurred during a period of 9 years from 2010 to 2018 in South Korea, using nationwide data provided by the Korean Health Insurance Review Assessment.5 The ICD-10 code S332 was used to identify coccyx fractures.5 A total of 238,906 patients were diagnosed with coccyx fracture from 2010 to 2018 using the ICD-10 criteria.5 The results provided valuable epidemiological information of this condition, such as the annual incidence (119.75/100,000) and seasonal variation (most frequent in winter, followed by summer).5 

A second example is a study completed by researchers in southeastern Iran that aimed to document the epidemiological features and outcomes of burn injuries in the region.6 The retrospective cross-sectional study was carried out at Khatam-Al-Anbiya Hospital, where the researchers analyzed thousands of inpatient records from April 2007 to March 2016.6 Burn patients’ records were selected according to the ICD-10 categories for burns and corrosions, codes T20-T32.6 According to the researchers, ICD-10 guidelines were used for two reasons.6 First, the ICD-10 contains detailed data on burns, including the site, severity, percentage, cause, and location of burn occurrence.6 Second, the documentation of burn data, based on ICD-10 directives, standardizes findings from burn injury analyses and leads to the comparability of data at national and international levels.6 After analyzing 3,030 burn patients, the results indicated important information about burn trends in southeastern Iran over a 10-year period.6 

Developed by the World Health Organization, the ICD-10 functions as the international standard for defining and reporting diseases and health conditions.7 Its use in epidemiological studies enables more direct comparability of data both between regions and within the same region over a period of time.7 Through its extensive list of codes, the ICD-10 allows the world to compare and share health information using a common language.7


  1. World Health Organization. (2020). Family of International Classifications (FIC). World Health Organization.
  1. National Center for Health Statistics. (2015). International Classification of Diseases, (ICD-10-CM/PCS) Transition – Background. U.S. Department of Health & Human Services.
  1. Lépine, J., & Lellouch, J. (1995). Classification and epidemiology of social phobia. European Archives of Psychiatry and Clinical Neuroscience, 244(6), 290-296.
  1. U.S. Department of Health & Human Services. (2011). Principles of Epidemiology in Public Health Practice (pp. 1-511). Atlanta: Centers for Disease Control and Prevention.
  1. Won, H., Moon, S., Park, J., Kim, J., Kim, H., & Baek, S. et al. (2020). Epidemiology and risk factors of coccyx fracture: A study using national claim database in South Korea. Injury, 51(10), 2278-2282.
  1. Alipour, J., Mehdipour, Y., & Karimi, A. (2020). Epidemiology and outcome analysis of 3030 burn patients with an ICD-10 approach. Annals of burns and fire disasters, 33(1), 3–13.
  1. World Health Organization. (2012). International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10). WHO Family of International Classifications Network.