Disease Codes -- the ICD

The International Statistical Classification of Diseases and Related Health Problems, usually called by the short-form name International Classification of Diseases (ICD), is the international "standard diagnostic tool for epidemiology, health management and clinical purposes".  The ICD is maintained by the World Health Organization, the directing and coordinating authority for health within the United Nations System.  The ICD is designed as a health care classification system, providing a system of diagnostic codes for classifying diseases, including nuanced classifications of a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or disease. This system is designed to map health conditions to corresponding generic categories together with specific variations, assigning for these a designated code, up to six characters long. Thus, major categories are designed to include a set of similar diseases.

The International Classification of Diseases is published by the World Health Organization (WHO) and used worldwide for morbidity and mortality statistics, reimbursement systems, and automated decision support in health care.  This system is designed to promote international comparability in the collection, processing, classification, and presentation of these statistics. As in the case of the analogous (but limited to mental and behavioral disorders) Diagnostic and Statistical Manual of Mental Disorders (DSM, currently in version 5), the ICD is a major project to statistically classify health disorders, and provide diagnostic assistance. The ICD is a core statistically-based classificatory diagnostic system for health care related issues of the WHO Family of International Classifications (WHO-FIC).

The ICD is revised periodically and is currently in its tenth revision. The ICD-10, as it is therefore known, was developed in 1992 to track health statistics. ICD-11 is planned for 2017. As of 2007, development plans included using Web 2.0 principles to support detailed revision.  Annual minor updates and triennial major updates are published by the WHO.  The ICD is part of a "family" of guides that can be used to complement each other, including also the International Classification of Functioning, Disability and Health which focuses on the domains of functioning (disability) associated with health conditions, from both medical and social perspectives.

History and usage in the United States

In the United States, the U.S. Public Health Service published The International Classification of Diseases, Adapted for Indexing of Hospital Records and Operation Classification (ICDA), completed in 1962 and expanding the ICD-7 in a number of areas to more completely meet the indexing needs of hospitals. The U.S. Public Health Service later published the Eighth Revision, International Classification of Diseases, Adapted for Use in the United States, commonly referred to as ICDA-8, for official national morbidity and mortality statistics. This was followed by the ICD, 9th Revision, Clinical Modification, known as ICD-9-CM, published by the U.S. Department of Health and Human Services and used by hospitals and other healthcare facilities to better describe the clinical picture of the patient. The diagnosis component of ICD-9-CM is completely consistent with ICD-9 codes, and remains the data standard for reporting morbidity. National adaptations of the ICD-10 progressed to incorporate both clinical code (ICD-10-CM) and procedure code (ICD-10-PCS) with the revisions completed in 2003. In 2009, the U.S. Centers for Medicare and Medicaid Services announced that it would begin using ICD-10 on April 1, 2010, with full compliance by all involved parties by 2013.

Mental and behavioral disorders

The ICD includes a section classifying mental and behavioral disorders (Chapter V). This has developed alongside the American Psychiatric Associations’s Diagnostic and Statistical Manual of Mental Disorders (DSM) and the two manuals seek to use the same codes. There are significant differences, however, such as the ICD including personality disorders in the same way as other mental disorders, while the DSM-IV-TR lists them on a separate 'axis'. The WHO is revising their classifications in these sections as part the development of the ICD-11 (scheduled for 2015), and an "International Advisory Group" has been established to guide this.  An international survey of psychiatrists in 66 countries comparing use of the ICD-10 and DSM-IV found that the former was more often used for clinical diagnosis while the latter was more valued for research.  The ICD is actually the official system for the US, although many mental health professionals do not realize this due to the dominance of the DSM. The US is due to adopt a modified version of the ICD-10 in 2013. Psychologists state, "Serious problems with the clinical utility of both the ICD and the DSM are widely acknowledged."

http://en.wikipedia.org/wiki/ICD