The Development, Evolution, and Modifications of ICD-10: Challenges to the International Comparability of Morbidity Data

The Development, Evolution, and Modifications of ICD-10: Challenges to the International Comparability of Morbidity Data

Post #52 Shortlink:

ICD, WHO, morbidity, ICD-10 clinical modifications, administrative data

Medical Care

doi: 10.1097/MLR.0b013e3181ef9d3e
Original Article: PDF Only

The Development, Evolution, and Modifications of ICD-10: Challenges to the International Comparability of Morbidity Data

Published Ahead-of-Print


Background: The United States is about to make a major nationwide transition from ICD-9-CM coding of hospital discharges to ICD-10-CM, a country-specific modification of the World Health Organization’s ICD-10. As this transition occurs, the WHO is already in the midst of developing ICD-11. Given this context, we undertook this review to discuss: (1) the history of the International Classification of Diseases (a core information “building block” for health systems everywhere) from its introduction to the current era of ICD-11 development; (2) differences across country-specific ICD-10 clinical modifications and the challenges that these differences pose to the international comparability of morbidity data; (3) potential strategic approaches to achieving better international ICD-11 comparability.

Literature Review and Discussion: A literature review and stakeholder consultation was carried out. The various ICD-10 clinical modifications (ICD-10-AM [Australia], ICD-10-CA [Canada], ICD-10-GM [Germany], ICD-10-TM [Thailand], ICD-10-CM [United States]) were compared. These ICD-10 modifications differ in their number of codes, chapters, and subcategories. Specific conditions are present in some but not all of the modifications. ICD-11, with a similar structure to ICD-10, will function in an electronic health records environment and also provide disease descriptive characteristics (eg, causal properties, functional impact, and treatment).

Conclusion: The threat to the comparability of international clinical morbidity is growing with the development of many country-specific ICD-10 versions. One solution to this threat is to develop a meta-database including all country-specific modifications to ensure more efficient use of people and resources, decrease omissions and errors but most importantly provide a platform for future ICD updates.

(C) 2010 Lippincott Williams & Wilkins, Inc.

Ed note: The forthcoming US “Clinical Modification”, ICD-10-CM, is country specific; it does not apply outside the US.

Current proposals for the US Clinical Modification ICD-10-CM, which is scheduled for implementation in October  2013, propose classifying Chronic fatigue syndrome in ICD-10-CM Chapter 18 at R53.82.

The proposed U.S. classification ICD-10-CM separates CFS and Postviral fatigue syndrome into mutually exclusive categories. “Chronic fatigue, unspecified | Chronic fatigue syndrome not otherwise specified” appear in Chapter XVII under R53.82.

Postviral fatigue syndrome | Benign myalgic encephalomyelitis” appear in Chapter VI under G93.3.

The Chronic Fatigue Syndrome Advisory Committee (CFSAC) had previously recommended CFS to be placed under the same neurological code as ME and PVFS, G93.3.

For the most recent ICD-10-CM proposals see:

CDC site: International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) [1]:

The Zipped file for the “2010 ICD-10-CM Tabular List of Diseases & Injuries” is not that easy to locate on the CDC site.

A non Zipped PDF of the most recent proposals can be downloaded here:

Page 325:

G93.3 Postviral fatigue syndrome
Benign myalgic encephalomyelitis
Excludes1: chronic fatigue syndrome NOS (R53.82)

Page 1165:

R53.82 Chronic fatigue, unspecified
Chronic fatigue syndrome NOS
Excludes1: postviral fatigue syndrome (G93.3)

The Canadian Clinical Modification (ICD-10-CA) has all three terms classified in Chapter VI: Diseases of the nervous system at G93.3:

Version 2009 ICD-10-CA Tabular List, Volume 1 PDF (4.9MB):

Other disorders of the nervous system



G93 Other disorders of brain


G93.3 Postviral fatigue syndrome
Includes: Benign myalgic encephalomyelitis
Chronic fatigue syndrome

Excludes: fatigue syndrome NOS (F48.0)

[1] Although this release of ICD-10-CM is now available for public viewing, the codes in ICD-10-CM are not currently valid for any purpose or use.

[2] More information on US “Clinical Modification” ICD-10-CM here, on DSM-5 and ICD-11 Watch site:


Comments are closed.

%d bloggers like this: