The ninth revision of the original (Bertillon’s) classification of causes of death is referenced in this article at the WHO website.

The conference for the ninth revision was held in 1975 and organised by the World Health Organisation. By the ninth revision there were various influential stakeholders creating a tension between conservation and change.

If there were big changes, then this would have practical implications (e.g. billing). On the other hand stakeholders had also requested changes to meet their needs and provide additional granularity.

The end result was ICD-9. Whilst ICD-10 was mandated for use in the UK in 1995, in the USA, ICD-9 it still continued to be used. If we compare the UK and USA healthcare systems, we see that the NHS system is a nationalised healthcare system while the USA healthcare system is insurance based. In the USA the billing system generates large numbers of daily transactions that are dependent on ICD coding. Thus large changes to the coding have the potential to impact on the overheads for the billing system.

The Center for Disease Control (CDC) has a useful website resource for ICD-9 and ICD-10 which can be found here. As they state on the website

The International Classification of Diseases (ICD) is designed to promote international comparability in the collection, processing, classification, and presentation of mortality statistics

In the USA, ICD-9 has been modified to improve clinical utility. This is referred to as ICD-9 CM (Clinical Modification). As recently as 2013, addenda to ICD-9 were being introduced.

Over in the United States there has been a heated debate about the benefits of moving from ICD-9 to ICD-10 and this has been delayed. This 2012 article goes into detail about the challenges associated with moving from ICD-9 to ICD-10. However the change to ICD-10 CM was mandated for October 2015 (with mortality coding changed in 1995).

Appendix A – Other Posts in the Series on Health Information Exchanges

A Literature Review of 40 years of SNOMED

Arizona Statewide Health Information Exchange

A History of The Health Information Exchange in Pennsylvania

The Arkansas Health Information Exchange – SHARE

The California Health Information Exchange – Cal Index

Creating a Health Information Exchange in Arizona

Health Information Exchanges

Health Information Exchanges and Chronic Conditions

HIPPA and Health Information Exchanges


ICD-SNOMED-CT® Harmonisation

ICD-1 – Well…near enough








Körner Data and SNOMED: A Snapshot from 1988

Mapping ICD 9 (or 10) to SNOMED CT®

Over 1 Million Relationships: SNOMED CT ®

Standardisation of Health Information Technology in New Zealand

Statisticians were Responsible for the Development of an International Classification of Diseases

Why Do We Need Electronic Record Systems to Talk to Each Other

Appendix B – Definition of Health Information Exchange

This is the definition of the Health Information Exchange that I use (Hersh et al, 2015)

Health information exchange (HIE), the electronic sharing of clinical information across the boundaries of health care organizations

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section.


  1. I appreciate your kindness to us! Our goal is to provide our seniors with personalized, quality services. Our experienced caregivers and staff have years of experience working with and among our community’s seniors.


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