Classification systems ICD Flashcards
What is the ICD?
international statistical classification of diseases and related health problems.
-Developed in 1893 to monitor global mortality and morbidity statistics (data on death and disease).
-revised often, current version (ICD-10) published in 1992 (ICD-11 due soon).
-a multilingual freely available resource used around the world, provides a ‘common language’ so that data collected in different countries can be usefully compared.
Mental disorders and ICD codes
Why does each section have leftover codes?
What are the codes used for?
What does the system try to be?
-chapter 5 of the ICD-10 is ‘mental and behavioural disorders’
-Each disorder has a code (starting with F), disorders are listed consecutively and there are 11 sections e.g
F20-F29 is ‘schizophrenia, schizotypal and delusional disorders’
F20 is the sub category of ‘schizophrenia’
F20.0 is ‘paranoid schizophrenia’, F20.1 is Hebephrenic schizophrenia’, ect.
-Each section has ‘leftover’ codes, so new disorders can be added without having to recode the others (e.g F48 is ‘other non psychotic mental disorders’)
-codes are used to index medical records (easy to find people with specific conditions for research).
-The system tries to be comprehensive enough to include all known conditions but also avoid repetition or overlap.
Making a diagnosis using the ICD-10
What type of disorders does the ICD use?
ICD contains both physical and psychological disorders.
The clinician making the diagnosis:
-Selects key words from the client interview relating to symptoms (e.g hallucinations and delusions)
-Looks of the symptoms in an alphabetical index or may go straight to an obvious section (e.g schizophrenia).
-uses other symptoms to locate a subcategory (e.g F20 then F20.1 based on presenting symptoms.
Improvements to the ICD-10
what do language and culture shape?
what does this lead to?
what was changed due to this posing problems for the international community?
what did this review process also reveal?
-Presentation, communication and interpretation of symptoms are shaped by language and culture, leads to culture bias. meaning clients from one culture could be given a different diagnosis when diagnosed by clinicians from another culture because of different cultural norms and language use.
-Poses problems for the internationa community served by the ICD. So a research programme was set up to review differences in diagnostic practice and terminology across the world. Now the ICD-1o is available in different languages and cultural forms.
-This review process also revealed inconsistencies, ambiguities and overlaps between disorders. These were removed from the ICD, so it is now clear, simple and logically organised.
Reliability of the ICD
strengths
Improved reliability between which two ICD?
who compared these two models?
What did PPV scores increase by?
what does this show?
good inter-rater reliability
-improved reliability between ICD-9 and ICD-10
-Ponizovsky et al (2006) compared the reliability of the ICD-9 and ICD-10 using PPV (positive predictive value), the proportion of people who get the same diagnosis when reassessed.
-PPV scored for schizophrenia increased from 68% in 1989 (ICD-9) to 94.2% in 2003 (ICD-10), an increase of 26.2%.
-This clearly shows improved reliability and suggests that the increased number of disorders from the ICD-9 to the ICD-10 has not detracted from the reliability of those diagnoses.
-Good inter-rater reliability
-two researchers carried out a joint interview with 100 clients (Galeazzi et al. 2004).
-looking at psychosomatic symptoms, kappa values ranged from 0.69 to 0.97 (very high agreement).
-This encourages confidence in using the ICD-10 at least for some disorders.
reliability of the ICD
counter argument
On the other hand
reliability is meaningless without a high level of validity. A demonstration of high stability of diagnoses, i.e reliability of a given diagnostic system, does not mean that the system is valid. Reliability on its own tells us nothing about the true meaning of the diagnosis.
validity of the ICD
strength
what did mason et al 1997 compare?
what does this show?
-good predictive validity for schizophrenia.
-mason et al. (1997) compared different ways of making a diagnosis.
-The ICD-9 and ICD-10 were reasonably good at predicting disability in 99 people with schizophrenia 13 years later.
-This shows that the initial diagnosis was useful and meaningful in terms of its ability to accurately predict future outcomes.
who compared different ways of making a diagnosis with the results being:
The ICD-9 and ICD-10 were reasonably good at predicting disability in 99 people with schizophrenia 13 years later.
Mason et al 1997
Validity of the ICD
application
what organisation aims to improve clinical utility?
what did an international survey of clinicians find?
-The ICD-10 continues to be effectively applied to diagnosis
-The WHO (world health organisation) aims to improve ‘clinical utility’ of the system in the ICD-11 by conducting research.
-An international survey of clinicians found a preference for simplicity and flexibility, so the ICD-11 task force is now cautious about adding new disorders.
-The system should become more user-friendly which means validity of diagnosis should also improve.
similarities
what approach do both systems take?
codes for diagnosis?
How are they set?
what do they both allow from new to old versions?
What are the criteria for both based on?
-both systems take an nosological approach and base the classification of mental disorders on psychopathology.
-share several similar codes for diagnosis
-DSM and ICD are code set which are nearly identical in many ways and permits classifying the diagnosis for healthcare and insurance processing processes.
-both allow cross walking from old to new versions. Allows the new version to have some definitions from the former versions.
-The criteria for both are not decided based on factual evidence but are approved by medical experts for research after reaching a consensus.
differences
accuracy
reliability
credence
purpose
Accuracy
- ICD, although it promptly assists in data collection, considered to be less accurate
-DSM, with clinical significance criteria and specificity in the description, considered to be far more accurate.
reliability
-ICD, considered to be less reliable as they reject diagnostic criteria without independent validation leading to disagreements in diagnosis.
-DSM, as operational criteria were introduced, the system is considered more reliable in a statistical context.
credence
I-CD, it is an official classification adopted by many nations around the world.
-DSM, official classification in the US but adopted by many countries aswell
Purpose
-ICD, used for classifying all illness and used by many health practitioners.
-DSM, used particularly by psychiatrists and it represents code set for all mental disorders.
