Year : 2018 | Volume
: 34 | Issue : 5 | Page : 5--10
Core considerations in the development of the world health organization's international classification of diseases, 11th Revision
Tahilia J Rebello1, Geoffrey M Reed2, Shekhar Saxena3,
1 Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, USA
2 Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, USA; Department of Mental Health and Substance Abuse, World Health Organization, Geneva, Switzerland
3 Department of Mental Health and Substance Abuse, World Health Organization, Geneva, Switzerland
Dr Geoffrey M Reed
Columbia Global Mental Health Program, Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, USA; Department of Mental Health and Substance Abuse, World Health Organization, Geneva, Switzerland
The World Health Organization (WHO) Department of Mental Health and Substance Abuse is updating the diagnostic guidelines for mental and behavioural disorders intended for inclusion in the International Classification of Diseases, 11th Revision (ICD-11). When ratified and implemented, the ICD-11 will serve as a global standard used across the world for varied purposes ranging from diagnosis, clinical management, health data collection and reporting, research, service and program planning, and policy development. Given the eventual ubiquity of the ICD-11 and its potentially significant impact on clinical practice and public health, WHO has identified three core organizing principles to guide ICD-11 development: 1.) maximizing the clinical utility or usefulness of the guidelines in the clinical context (e.g., ease-of-use, goodness-of-fit, clarity, feasibility of implementation); 2.) assessing the clinical consistency or reliability of the guidelines; and 3.) ensuring the global applicability of the system to clinicians working in diverse settings worldwide. This article provides a review of each of these three core considerations, specifying rationale for their selection and defining the various mechanisms designed by WHO to assess and enhance these key elements of the ICD-11.
|How to cite this article:|
Rebello TJ, Reed GM, Saxena S. Core considerations in the development of the world health organization's international classification of diseases, 11th Revision.Indian J Soc Psychiatry 2018;34:5-10
|How to cite this URL:|
Rebello TJ, Reed GM, Saxena S. Core considerations in the development of the world health organization's international classification of diseases, 11th Revision. Indian J Soc Psychiatry [serial online] 2018 [cited 2021 Oct 17 ];34:5-10
Available from: https://www.indjsp.org/text.asp?2018/34/5/5/245835
A core constitutional responsibility of the World Health Organization (WHO) is the establishment, maintenance, and revision of its global nosology system: The International Classification of Diseases (ICD) and related health problems. The ICD represents the major global diagnostic classification system utilized by all the 193 WHO member nations as their official system for collecting and reporting health data. Beyond health statistics, the ICD is employed for a multitude of diverse purposes including basic science, clinical and population-level research, program and policy development, and training. Primarily, the ICD serves as an important diagnostic tool for clinicians, and it is the main system used for clinical purposes across the globe.
The current version of the ICD, the Tenth Revision (ICD-10), was developed in the late 1980s and published in 1992. The specific Clinical Descriptions and Diagnostic Guidelines (“Blue Book”), containing more comprehensive material on the mental and behavioral disorders, was also published that same year. Although the ICD-10 underwent occasional updates to reflect advancements in knowledge and scientific/clinical conceptualizations of certain health conditions, a more systematic and thorough update process was initiated by the WHO in 2005. This update called for the revision of the diagnostic guidelines for all health conditions in the ICD, including the chapter on mental and behavioral disorders. The technical and logistical responsibility for developing the mental and behavioral disorder guidelines for the next version of the ICD (ICD-11) lies within the WHO Department of Mental Health and Substance Abuse (MSD). To direct the process of developing the ICD-11 chapter on mental and behavioral disorders, MSD convened a cadre of international mental health experts to serve on the International Advisory Group for the revision of ICD-10. The Advisory Group was tasked with identifying the key guiding principles and goals of the revision and to elucidate a process to meet these targets. The overarching principle to guide ICD-11 development, agreed on by the advisory group, was to develop a system that maximally improves clinical outcomes, thereby allowing countries to use the ICD-11 as a resource to reduce the burden of disease attributed to mental and behavioral disorders. In line with this principle, three goals were identified:  to maximize the clinical utility, or usefulness, of the classification system to clinicians working in varied clinical settings;  to validate the consistent and reliable implementation of the guidelines, or their “clinical consistency;” and  to serve WHO's geographically, culturally, economically, and lingually diverse constituency by enhancing the global applicability and acceptability of the system to clinicians worldwide. Although these goals may seem clinically focused, all the three priorities are wholly consistent with the WHO's public health mission to lower the disease burden caused by mental health and behavioral disorders, and to allow for the “attainment of the highest possible level of health for all peoples,” including mental health.
To meet these goals, the Advisory Group established disorder-specific Working Groups (WGs), comprised of international mental health professionals with relevant scientific and/or clinical expertise in the various disorder areas (e.g., anxiety disorders and mood disorders). Each WG consisted of members from all the WHO global regions with substantial representation from low- and middle-income countries. The responsibility of the WGs was to review the current corpus of research from the basic science, clinical, public health, and policy domains, within various health-care, geographical, and resource-level settings across the world. Based on this thorough scientific review, the WGs recommended specific modifications to the current ICD guidelines, and provided draft proposals for ICD-11, for their respective disorder areas.
To ensure that the proposed guidelines were aligned with the overarching goals of the revision, the Advisory Group recommended a rigorous program of field studies to test the clinical utility, consistency, and global applicability of the proposed guidelines. Scientific direction for the field studies was provided by the ICD-11 Field Studies Coordination Group (FSCG) composed of global leaders in the mental health field from Centres of Excellence in clinical care, scientific research, and public health, from 12 countries representing 60% of the world's population. FSCG members lend not only their technical expertise to design of the field studies, but also serve as essential facilitators allowing for successful engagement of global clinicians and researchers and the effective implementation of ICD-11 research initiatives across the world.
This review provides rationale for the selection and testing of the three core considerations in ICD-11 development: clinical utility, clinical consistency, and global applicability.
Improving the clinical utility of the ICD-11 mental and behavioral disorder guidelines has been a core principle governing the development and evaluation of the diagnostic material and will undoubtedly impact the adoption and implementation of the ICD-11 when it is published in 2019. Based on earlier conceptualizations of the term, the International Advisory Group identified a functional definition of “clinical utility.”,, For the purposes of ICD-11 development, the “clinical utility” of the classification system and/or diagnostic material is assessed based on: (a) its ability to be easily and accurately implemented by clinicians with diverse disciplinary and training backgrounds, working in varied clinical contexts across the globe. This includes how well and accurately the diagnostic material fits patient presentations (i.e., goodness of fit), how easy the guidelines are to understand, conceptualize, and apply (i.e., ease of use), and the time required for clinicians to apply the guidelines to arrive at a diagnostic conclusion (i.e., feasibility); (b) its value in facilitating communication between users (e.g., among clinicians, with patients, families, and administrators); and (c) its usefulness in making clinical management decisions and selecting interventions., A particular emphasis was made to maximize the utility of the system to clinicians working in low- and middle-income countries and low-resource settings.
Although seemingly clinically- and patient-focused, the goal of improving the clinical utility of the ICD-11 guidelines is highly consistent with the WHO's role as a global public health agency. By creating a classification system that serves as an effective, accurate, and feasible diagnostic tool, the ICD-11 will allow for the identification of people who require mental health services and may facilitate the selection of more appropriate and effective treatments for them and to assess their prognosis and monitor their progress. To be a better tool for reducing the disease burden of mental health conditions, the new system will need to be useful and usable throughout the world at the points where people with mental health needs are most likely to come into contact with opportunities for care: the clinical context. As previously noted, “A mental disorders classification that is difficult and cumbersome to implement in clinical practice and does not provide information that is of immediate value to the clinician has no hope of being implemented accurately at the encounter level in real-world health-care settings. In that event, clinical practice will not be guided by the standardization and operationalization of concepts and categories that are inherent in the classification, and important opportunities for practice improvement and outcome assessment will be lost. In turn, a diagnostic system that is characterized by poor clinical utility at the encounter level cannot generate data based on those encounters that will be a valid basis for health programs and policies, or for global health statistics.” Thus, enhancing the clinical utility of the ICD-11 is a major public health priority for the WHO.
To evaluate and maximize the clinical utility of the proposed ICD-11 guidelines, the WHO initiated a systematic and rigorous research program consisting of formative and evaluative field studies. The field studies were designed to collect clinical utility data from a broad spectrum of clinicians and clinical settings, across varied geographical, cultural, resource-level, and lingual contexts. The formative field studies included large international surveys of thousands of health professionals and collected data on how global clinicians conceptualize the relationships among mental disorders and how mental disorders should be structured and presented to correspond the best to clinical practice (e.g., the ideal content and format of the diagnostic material such as the preferred number of categories and flexibility of the guidelines)., These data sculpted the overall organization and architecture of the ICD-11 chapter on mental and behavioral disorders (e.g., its linear structure, the structure and formatting of diagnostic material) and provided the WHO and the WGs with an insight on the current behaviors, preferences, and needs of clinicians as related to the classification systems for mental health conditions. This in turn guided the development of the proposed diagnostic material by the WGs. The proposed diagnostic guidelines are currently being tested in a series of case–controlled (Internet-based) and ecological implementation (clinic-based) field studies. The case–controlled studies assess the clinical utility ratings of the proposed ICD-11 guidelines, as well as test their accuracy in application to standardized case vignettes. These studies are conducted in up to six languages (Chinese, English, French, Japanese, Spanish, and Russian) with participation from members of the WHO's Global Clinical Practice Network (GCPN). The GCPN consists of over 14,500 mental health professionals in 154 countries. GCPN members have more than 16 years of professional experience, on average. Nearly 93.2% of them actively see patients and 58.9% provide clinical supervision. The GCPN includes all major mental health disciplines (physicians, including psychiatrists, primary care clinicians, and other specialties: 54%; psychologists: 30%; others: 4.6%; counselors, occupational therapists, and social workers: 3% each; and nursing: 2.4%). As such, GCPN members are well poised to provide data on the clinical utility of the proposed ICD-11, through their participation in field studies and other online review mechanisms. Through the case–controlled field studies, the WHO will collect clinical utility data for nearly all the major mental and behavioral disorder groupings.
In parallel, the WHO is implementing ecological implementation field studies which assess the utility of the proposed guidelines when applied by practicing clinicians to real patients in the varied global clinical settings in which they will be ultimately implemented. These studies assess the clinical utility for those mental disorders that account for the highest percentage of global disease burden and use of mental health services in clinical settings in diverse countries representing all the WHO global regions, as well as important classification changes proposed for the ICD-11. Studies will be conducted in the areas of schizophrenia and other psychotic disorders, mood disorders, anxiety disorders, stress-related disorders, obsessive-compulsive and related disorders, and feeding and eating disorders. These clinic-based utility studies are being conducted at multiple sites in varied countries including Brazil, China, India, Italy, Japan, Mexico, Nigeria, Russia, and the United States, where about 60% of the world's population resides.
Beyond the ease of use, goodness of fit, and feasibility of the guidelines, the evaluative field studies will assess the following clinical utility elements of the proposed ICD-11 guidelines: (a) clarity and how easy the guidelines were to understand; (b) level of detail and specificity; (c) extent to which the guidelines had requirements that were difficult to assess and/or apply; (d) description of the boundary between disorder and normality; (e) description of the boundary between disorders; (f) usefulness of the diagnostic guidelines, including the qualifiers (e.g., severity level and course qualifiers), in selecting a treatment and assessing prognosis; (g) its use for communicating with other users (e.g., health professionals, patients, and their families); and (h) for education purposes.
Taken together, field study results will assist the WHO in enhancing the usefulness of the system to global mental health practitioners, by utilizing the data to inform improvements in the content, structure, presentation, and other elements of the proposed ICD-11 guidelines with the goal of maximizing its clinical utility in varied global settings.
The extent to which diagnostic guidelines can be consistently or reliably applied by independent health professionals, working in varied clinical contexts, is an important implementation characteristic of a classification system. The consistent application of diagnostic material may be indicative of its validity, as a diagnostic system cannot be valid if it is not reliable. This is especially true in the absence of defined endophenotypes, biomarkers, and diagnostic tests, as is the case with psychiatric diagnoses.,, Assessing the consistency of the clinical application of diagnostic guidelines may help determine their content validity, or how clearly they define the features of mental and behavioral disorders. Clinical consistency is also arguably interrelated with clinical utility, as reliably applied guidelines are more likely to serve as a valuable clinical tool for treatment selection and promoting continuity of care and for communication between health professionals, patients, and other users.
Along with patient- and clinician-related factors, the content and structure of the classification system strongly influences the reliable application of the guidelines. As such, the WHO has prioritized assessment of the clinical consistency of the proposed ICD-11 diagnostic guidelines to determine whether they can be reliably applied by clinicians working in diverse clinical contexts across the globe. To do so, the WHO is implementing ecological implementation (clinic-based) field studies in over 25 study sites, in 14 countries, representing highly divergent contexts, all the WHO global regions, and about 60% of the world's population. Studies are being conducted in five languages (Chinese, English, Japanese, Russian, and Spanish) in the following countries: Brazil, Canada, China, Egypt, India, Italy, Japan, Lebanon, Mexico, Nigeria, Russia, South Africa, Spain, Tunisia.
The clinical consistency study covers mental disorders that have the highest disease burden, place a substantial demand on mental health services worldwide, and are of relevance to participating countries, as well as on the extent of the changes proposed for them in the ICD-11. The study comprises three protocols: Protocol 1: schizophrenia and other primary psychotic disorders and mood disorders for adult patients who present with any psychotic symptom; Protocol 2: mood disorders, anxiety disorders, and disorders specifically associated with stress, for adult patients who present with relevant symptoms, but do not present with psychotic symptoms; and Protocol 3: common childhood mental disorders (attention-deficit hyperactivity disorder, disruptive behavior and dissocial disorders, mood disorders, and anxiety disorders) for child and adolescent patients with relevant symptoms. The research question addressed by the clinical consistency study is to determine whether two independent clinicians, based on the same information, arrive at the same diagnostic conclusion using the proposed ICD-11 diagnostic guidelines (i.e., inter-rater agreement). The study design is specifically intended to test the impact of the ICD-11 diagnostic material on clinical consistency and minimizes the impact of other sources such as patient factors since the two clinician raters simultaneously participate in the patient interview used to determine the diagnostic formulation and have access to the same patient information (e.g., laboratory tests and other nonpsychiatric diagnoses). Moreover, participating clinician raters undergo a brief training on the ICD-11 guidelines under study and register through an online system prior to data collection. As such, clinician-related factors such as extent of exposure or familiarity with the ICD-11 guidelines, years of professional experience, and other relevant factors can be minimized, analyzed, or controlled for when measuring clinical consistency. This allows for further isolation of the impact of the guidelines themselves on the consistency outcomes.
Data from the clinical consistency protocols will help identify disorders for which the proposed guidelines are associated with less reliable implementation and may help inform modifications to the guidelines and/or the focus of future training programs for clinicians when the ICD-11 is published and adopted. Findings from these studies show high clinical consistency of the guidelines, across the disorder groups and within the diverse clinical and geographical contexts in which the guidelines were tested.
Once published and adopted, the ICD-11 will serve as a tool for clinicians working in varied contexts across the globe. Thus, an important consideration for ICD-11 development is whether the diagnostic content within the ICD-11 is useful, relevant, and acceptable to clinicians working in different regions, countries, cultures, and resource levels, who practice in a variety of languages. The WHO has prioritized assessing and maximizing the global applicability of the ICD-11 from the very inception of the revision process. The International Advisory Group which set the priorities and goals for ICD-11 development, and continues to direct the process, includes multilingual members from all global regions including a high proportion from low- and middle-income countries. Similarly, the disorder-specific WGs who proposed modifications to the guidelines, as well as the FSCG which manages the design and implementation of field studies that test the ICD-11, have all included members with diverse geographical and lingual backgrounds, many of whom have direct experience practicing in low-resource contexts and within varying cultures.
In addition, the ICD presents diagnostic information as guidelines rather than as strict criteria. This was a deliberate choice by the WHO based on findings in the formative studies indicating a preference of clinicians, working across global areas, for more flexible diagnostic material., Precise requirements and cutoffs relating to symptom counts and duration are included only in cases where there are empirical data established across geographical regions and cultures, or other compelling reasons that support their inclusion. The flexible language of the ICD-11 is intended to increase its global applicability and its clinical utility by allowing for cultural variations in patient presentations, differences in clinical and health system factors that may affect diagnostic practice, and other culture-, country-, or regionally-relevant information that can impact the diagnostic process. Initial findings from the clinical consistency ICD-11 ecological implementation field studies indicate that, despite their flexible nature, the proposed guidelines are fairly reliably implemented in divergent clinical and country contexts.
A third way in which the ICD-11's global applicability is being assessed and enhanced is via the rigorous set of field studies, both formative and evaluative., In addition to the aforementioned core considerations of utility and consistency, these studies examine whether the proposed guidelines are suitable for use globally, by testing their implementation in varied contexts in widely divergent countries. The early formative studies which helped shape the architecture and linear structure of the chapter on mental and behavioral disorders involved thousands of clinicians from over forty countries and were conducted in multiple languages., Comparably, the evaluative case–controlled field studies have included participation from over 14,500 clinicians who are part of the GCPN who reside and practice in 154 countries across all global regions (Europe: 39%, The Western Pacific region: 27%, The Americas: 23%, South-East Asia: 5%, Africa: 3%, and The Eastern Mediterranean region: 3%). Thirty-seven percent of the pool of ICD-11 field study participants reside in low- and middle-income countries and are multilingual in terms of their professional language (English: 29%, Chinese: 15%, other: 12%, Spanish: 11%, French and Japanese: 8% each, German and Russian: 7% each, Portuguese: 3%, and Arabic: 2%). There are over 25 study sites for the ecological implementation studies in 16 very divergent countries (Brazil, Canada, China, Egypt, Germany, India, Italy, Japan, Lebanon, Mexico, Nigeria, Russia, South Africa, Spain, Tunisia, and the United States). Hundreds of clinicians in these countries are directly providing feedback related to the application of the ICD-11 in their diverse, global settings. Data from these field studies are used to identify and address differences in the implementation of the guidelines across varied global contexts.
The ICD-11 will also include a section titled, “Culture-related features” that will address documented issues related to the clinical presentation and diagnosis of each condition, which may be impacted by the cultural or geographical context of their implementation. Finally, given that the purveyors of mental health care in most parts of the world, especially in low- and middle-income countries, are nonspecialists, a primary care version of the ICD-11 is being developed, in parallel.
Testing and maximizing the clinical utility, clinical consistency, and global applicability of the diagnostic material has been the primary goal for the WHO as it develops the ICD-11 chapter on mental and behavioral disorders. In addition to being of importance at the patient or clinical level, these core considerations are highly congruent with the public health priorities of WHO. By serving as a clinically useful, reliable, and globally applicable diagnostic tool for clinicians working in diverse settings across the globe, the ICD-11 will provide a more effective tool for assisting clinicians in identifying the people in need of mental health services, as well as for selecting treatments and management strategies most likely to be effective for them, assessing their prognosis, and monitoring their progress and outcomes. Ideally, the ICD-11 guidelines will assist the WHO member states to reduce the disease burden associated with mental disorder in their countries. In this way, the ICD-11 helps advance the important objectives outlined in the WHO's Mental Health Action Plan 2013–2020, which provides a roadmap, framework, and measurable target for reducing the disease burden of mental and behavioral disorders and enhancing mental health worldwide. The draft diagnostic guidelines for the ICD-11 mental and behavioral disorders are available for review and comment, and membership for the GCPN remains open on an ongoing basis. Qualified mental health and primary care professionals are welcome to register by visiting https://gcp.network. The final version of the ICD-11 is currently scheduled for review and ratification by the World Health Assembly in 2019.
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