ICD coding for epilepsy: Past, present, and future A report by the International League Against Epilepsy Task Force on ICD codes in epilepsy

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1 SPECIAL REPORT ICD coding for epilepsy: Past, present, and future A report by the International League Against Epilepsy Task Force on ICD codes in epilepsy * Nathalie Jette, Ettore Beghi, Dale Hesdorffer, Solomon L. Moshe, #**Sameer M. Zuberi, Marco T. Medina, and Donna Bergen SUMMARY Dr. Nathalie Jette is an associate professor in clinical neurosciences at the University of Calgary. The World Health Organization (WHO) International Classification of Diseases (ICD) has been used to classify causes of morbidity and mortality such as epilepsy for more than 50 years. The aims of this critical commentary are to do the following: (1) Introduce the ICD classification, summarize the ICD-9 and ICD-10 codes for epilepsy and seizures, and discuss the challenges of mapping epilepsy codes between these two versions; (2) discuss how the ICD-9 and ICD-10 relate to the revised International League Against Epilepsy (ILAE) terminology and concepts for classification of seizures and epilepsies; (3) discuss how ICD-coded data have been used for epilepsy care and research and briefly examine the potential impact of the international ICD-10 clinical modifications on research; (4) discuss the upcoming ICD-11 codes and the role of the epilepsy community in their development; and (5) discuss how the ICD-11 will conform more closely to the current ILAE terminology and classification of the epilepsies and seizures and its potential impact on clinical care, surveillance, and public health and research. KEY WORDS: International Classification of Diseases, ICD-10, ICD-11, WHO, Morbidity, Administrative data. Accepted November 17, 2014; Early View publication February 12, *Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Sciences and Institute for Public Health, University of Calgary, Calgary, Alberta, Canada; Department of Neurosience, IRCCS Institute for Pharmacological Research Mario Negri, Milano, Italy; GH Sergievsky Center and Department of Epidemiology, Columbia University, New York, New York, U.S.A.; Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience and Department of Pediatrics, Laboratory of Developmental Epilepsy, Montefiore/Einstein Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, U.S.A.; #Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow, United Kingdom; **School of Medicine, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom; Faculty of Medical Sciences, National Autonomous University of Honduras, Tegucigalpa, Honduras; and Department of Neurological Sciences, Rush University, Chicago, Illinois, U.S.A. Address correspondence to Dr. Nathalie Jette, Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Street NW, Calgary, Alberta, AB T2N 2T9, Canada. nathalie. jette@albertahealthservices.ca Wiley Periodicals, Inc International League Against Epilepsy The International Classification of Diseases, Ninth and Tenth Revision (ICD-9 and ICD-10) Codes for Epilepsy, and the Challenges of Mapping Epilepsy Codes between These Two ICD Versions In 1948, the World Health Organization (WHO) was charged by the new United Nations to update and promulgate the global use of the International Classification of Diseases (ICD). 1 The revised version, ICD-6, released in 1949, was expanded to address causes of mortality and morbidity. 2,3 Periodic revisions followed. The subsequent two ICD revisions incorporated only minor changes. More substantial revisions were introduced in the ICD-9 and ICD-10 (Table 1). 1 For example, the ICD-9 provided the 348

2 349 ICD Coding for Epilepsy Table 1. ICD-9 and ICD-10 epilepsy and seizure-related codes ICD Epilepsy and recurrent seizures a Generalized nonconvulsive epilepsy Generalized convulsive epilepsy Localization-related (focal) (partial) epilepsy and epileptic syndromes with complex partial seizures Localization-related (focal) (partial) epilepsy and epileptic syndromes with simple partial seizures Infantile spasms Epilepsia partialis continua Other forms of epilepsy and recurrent seizures (e.g. gelastic epilepsy) Epilepsy, unspecified 345 Epilepsy and recurrent seizures a Petit mal status Grand mal status Convulsions Febrile convulsions (simple), unspecified Complex febrile convulsions Other convulsions ICD-10 G40 Epilepsy G40.1 Localization-related (focal)(partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures (which can evolve to secondarily generalized seizures) G40.2 Localization-related (focal)(partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures (which can evolve to secondarily generalized seizures) Generalized idiopathic epilepsy and epileptic syndromes b G40.4 Other generalized epilepsy and epileptic syndromes c G40.5 Special epileptic syndromes d G40.6 Grand mal seizures, unspecified (with or without petit mal) G40.7 Petit mal, unspecified, without grand mal seizures Other epilepsy G40.9 Epilepsy, unspecified G41 Status epilepticus G41.0 grand mal status epilepticus G41.1 Petit mal status epilepticus G41.2 Complex partial status epilepticus G41.8 Other status epilepticus G41.9 Status epilepticus, unspecified R56 Convulsions, not elsewhere classified R56.0 Febrile convulsions (code here if simple) R56.8 Other and unspecified convulsions 333 Other extrapyramidal disease and abnormal disorders Myoclonus Familial essential myoclonus Progressive myoclonic epilepsy Unverricht-Lundborg disease Use additional E code to identify drug, if drug-induced 779 Other and ill-defined conditions originating in the perinatal period Convulsions in newborn 300 Anxiety, dissociative and somatoform disorders Dissociative, conversion and factitious disorders Conversion disorder P90 Convulsions of newborn F44 Dissociative (conversion) disorders F44.5 Dissociative convulsions F80 Specific developmental disorders of speech and language F80.3 Landau-Kleffner syndrome a The following fifth digit subclassification can be added to any of the codes in some of the international ICD modifications (e.g., ICD-9-CM): 0 without mention of intractable epilepsy and 1 with intractable epilepsy. b Includes any of the generalized idiopathic epilepsies whether convulsive or non-convulsive such as childhood absence epilepsy, juvenile myoclonic epilepsy, benign myoclonic epilepsy in infancy, etc. and nonspecific epileptic seizures (e.g., atonic, clonic, myoclonic, tonic, etc.). c Includes epilepsy with myoclonic absences, myoclonic astatic seizures, infantile spasms, Lennox-Gastaut syndrome, West syndrome, symptomatic early myoclonic encephalopathy, Salaam attacks. d Includes epilepsia partialis continua but also epileptic seizures related to alcohol, drugs, hormonal changes, sleep deprivation and stress. option of coding at the fourth- or fifth-digit level (e.g., ICD-9 Code Generalized convulsive epilepsy), whereas ICD-10 switched to an alpha-numeric coding system (e.g., Generalized idiopathic epilepsy and epileptic syndromes). For epilepsy, the 1976 numeric ICD-9 coding system, still in use by the United States, Canada, and many other countries today, focuses on seizure types and offers coding based on whether the seizures constituting the epilepsy are localization-related, that is, focal (partial); or generalized, with additional codes for a few special occurrences such as status epilepticus, infantile spasms, or epilepsia partialis continua. By the time the alpha-numeric ICD-10 classification system was released in 1989, however, epileptologists had begun to dichotomize the majority of epilepsies into syndromes, which were clearly or presumably symptomatic, and those which were idiopathic and of presumed genetic origin. Each of these major categories could cause localization-related or generalized seizures, and this was reflected in the major ICD-10 codes (Table 1). The country-specific ICD-10 classifications (e.g., ICD-10-CA and ICD-10-CM, see subsequent text) also provided an

3 350 N. Jette et al. Table 2. Mapping of ICD-9 onto ICD-10 epilepsy and seizure-related codes Example ICD-9 ICD Epilepsy and recurrent seizures G40 Epilepsy Childhood absence epilepsy not further characterized Lennox Gastaut syndrome with atypical absence seizures and atonic seizures Childhood absence epilepsy without generalized tonic clonic seizures Generalized nonconvulsive epilepsy Generalized idiopathic epilepsy and epileptic syndromes Generalized nonconvulsive epilepsy G40.4 Other generalized epilepsy and epileptic syndromes Generalized nonconvulsive epilepsy G40.7 Petit mal, unspecified, without grand mal seizures Juvenile myoclonic epilepsy Generalized convulsive epilepsy Generalized idiopathic epilepsy and epileptic syndromes Lennox Gastaut syndrome with tonic, myoclonic and generalized tonic-clonic seizures Epilepsy with generalized bilateral convulsive seizures (e.g. generalized tonic-clonic seizures) not further characterized Generalized convulsive epilepsy G40.4 Other generalized epilepsy and epileptic syndromes Generalized convulsive epilepsy G40.6 Grand mal seizures, unspecified (with or without petit mal) Absence status epilepticus Petit mal status G41.1 Petit mal status epilepticus Generalized tonic-clonic status epilepticus Grand mal status G41.0 Grand mal status epilepticus Complex partial status epilepticus G41.2 Complex partial status epilepticus Myoclonic status epilepticus G41.8 Other status epilepticus Status epilepticus unspecified G41.9 Status epilepticus, unspecified Focal dyscognitive seizures of temporal lobe origin but of unknown etiology Focal dyscognitive seizures due to remote traumatic brain injury evolving to bilateral convulsive activity Focal non-dyscognitive seizures of temporal lobe origin but of unknown etiology Focal non-dyscognitive seizures due to remote traumatic brain injury evolving to bilateral convulsive activity Localization-related (focal) (partial) epilepsy and epileptic syndromes with complex partial seizures Localization-related (focal) (partial) epilepsy and epileptic syndromes with complex partial seizures Localization-related (focal) (partial) epilepsy and epileptic syndromes with simple partial seizures Localization-related (focal) (partial) epilepsy and epileptic syndromes with simple partial seizures G40.0 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset G40.2 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures (which can evolve to secondarily generalized seizures) G40.0 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset G40.1 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures (which can evolve to secondarily generalized seizures) Infantile spasms Infantile spasms G40.4 Other generalized epilepsy and epileptic syndromes Epilepsia partialis continua Epilepsia partialis continua G40.5 Special epileptic syndromes Gelastic epilepsy Writing epilepsy Other forms of epilepsy and recurrent seizures Other epilepsy Epilepsy, unspecified Epilepsy, unspecified G40.9 Epilepsy, unspecified Continued

4 351 ICD Coding for Epilepsy Table 2. Continued. Example ICD-9 ICD Convulsions R56 Convulsions, not elsewhere classified Simple febrile seizure Febrile convulsions (simple), unspecified R56.0 Febrile convulsions Complex febrile seizure Complex febrile convulsions R56.0 Febrile convulsions Provoked (acute) seizures (not epilepsy) Other convulsions R56.8 Other and unspecified convulsions 649 Other conditions or status of the mother complicating pregnancy, childbirth or the puerperium Epilepsy complicating pregnancy, childbirth, or the puerperium 333 Other extrapyramidal disease and abnormal disorders Progressive myoclonic epilepsy Myoclonus Generalized idiopathic epilepsy and epileptic syndromes Familial essential myoclonus Progressive myoclonic epilepsy Unverricht-Lundborg disease Use additional E code to identify drug, if drug-induced 779 Other and ill-defined conditions originating in the perinatal period Convulsion of newborn Convulsions in newborn P90 Convulsions of newborn 300 Anxiety, dissociative and somatoform disorders F44 Dissociative (conversion) disorders Dissociative, conversion and factitious disorders Non-epileptic (psychogenic) seizures Conversion disorder F44.5 Dissociative convulsions Landau-Kleffner syndrome 315 Specific delays in development F80 Specific developmental disorders of speech and language Expressive language disorder F80.3 Landau-Kleffner syndrome e.g. developmental aphasia important option to add a fifth-digit modifying code that identified the presence and absence of intractable epilepsy. 1 The conceptual differences in the ICD-9 and ICD-10 precluded construction of a simple map from one to the other, for the classification of many patients. This is demonstrated in Table 2, wherein an attempt is made to map ICD-9 epilepsy and seizure-related codes onto ICD-10 codes. Additional ICD-10 codes without a corresponding ICD-9 code are listed. A number of ICD-9 codes can also be mapped onto more than one ICD-10 code. For example, childhood absence epilepsy, would be coded as Generalized nonconvulsive epilepsy in ICD-9, but in ICD-10 could be mapped to either the ICD-10 Generalized idiopathic epilepsy and epileptic syndromes, if not further characterized, or to G40.7 Petit mal, unspecified, without grand mal seizures if generalized tonic clonic seizures were absent. Focal dyscognitive seizures caused by a remote traumatic brain injury would be coded to Localization-related (focal) (partial) epilepsy and epileptic syndromes with complex partial seizures in ICD-9 and G40.2 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures in ICD- 10. However, focal dyscognitive seizures of temporal lobe origin but of unknown etiology would be coded to the same ICD-9 code as the preceding (G40.2), but G40.0 Localization-related (focal) (partial) idiopathic epilepsy and epilepsy syndromes with seizures of localized onset would be used in ICD-10. The Relationship between ICD-9, ICD-10, and the Revised ILAE Terminology and Concepts for Organization of Seizures and the Epilepsies In 2010, the first major development in the classification of the epilepsies since 1985 was proposed by the ILAE Commission on Classification & Terminology. 4 6

5 352 N. Jette et al. ILAE Revised Terminology for Classifica on of Seizures and Epilepsies mapped to ICD-9 and ICD-10 codes Classifica on of Seizures Tonic-Clonic G40.6 Typical Generalized seizures Arising within and rapidly engaging bilaterally distributed networks Absence * G40.7 Absence with special features -Myoclonic absence -Eyelid Myoclonia Clonic Atypical Tonic Atonic *Not coded in ICD-9 *Not coded in ICD-10 Myoclonic -Myoclonic -Myoclonic-atonic Focal seizures Origina ng within networks limited to one hemisphere Characterized according to one or more features: Aura Motor Autonomic Awareness/Responsiveness: altered (dyscogni ve) Or retained May evolve to Bilateral convulsive seizure G40.6 Unknown Insufficient evidence to classify as focal, generalized or both G40.9 Epilep c Spasms G40.4 Electroclinical Syndromes and Other Epilepsies Grouped by Specificity of Diagnosis Electroclinical syndromes Neonatal period Infancy Childhood Adolescence - Adult Self limited neonatal seizures Self limited familial neonatal epilepsy Ohtahara syndrome Early myoclonic encephalopathy P90 Febrile seizures R56 Febrile seizures plus (FS+) Self limited infan le epilepsy West syndrome G40.4 Dravet syndrome Myolclonic epilepsy in infancy Epilepsy of infancy with migra ng focal seizures Febrile seizures R56 Febrile seizures plus Early onset occipital epilepsy (Panayiotopoulos syndrome) Epilepsy with myoclonic atonic (previously asta c) seizures G40.4 Childhood absence epilepsy (assuming having only absence seizures) Self limited epilepsy with centrotemporal spikes (assuming having seizures without impaired) Autosomal dominant nocturnal frontal lobe epilepsy (assuming having seizures with impaired awareness) G G40.0 Lennox-Gastaut syndrome G40.4 Epilep c encephalopathy with con nuous spike-and-wave during sleep Landau-Kleffner syndrome F80.3 Juvenile absence epilepsy (assuming having only absence seizures) Juvenile myoclonic epilepsy (assuming having only myoclonic seizures) Epilepsy with generalised tonic-clonic seizures alone Autosomal dominant epilepsy with auditory features (assuming having seizures without impaired awareness i.e. simple par al seizures) Other familial temporal lobe epilepsies (assuming having seizures with impaired awareness i.e. complex par al seizures) G G40.0 Figure 1. ILAE Revised Terminology for Classification of Seizures and Epilepsies mapped to ICD-9 and ICD-10 codes. Epilepsia ILAE Over the last two decades, advances in neuroimaging, neurophysiology, and genetics have resulted in much greater understanding of the causes of epilepsy, which has in turn influenced management of epilepsy. The backbone of the 2010 classification is seizure type, syndrome, and etiology. 6 This classification is designed to reflect these advances and aid the clinical diagnostic process, emphasizing to health care workers that assessing an individual with epilepsy begins with describing the seizure type, or where possible defining an epilepsy syndrome, and classifying etiology. Figure 1 shows some ways in which the new ILAE classification of seizures and epilepsy corresponds to some of the ICD-9 and ICD-10 diagnostic codes, 6 and points out the many instances in which an automatic map, which will transfer a patient s diagnosis from one system to another is not always possible. First, the ILAE system clearly distinguishes between codes for seizures and codes for epilepsy, a dichotomy not consistently recognized by either ICD coding system. The ILAE s term Focal seizures: Originating within networks limited to one hemisphere, for example, would find no counterpart in either ICD system. If a specific focal epilepsy syndrome were diagnosed, however, most epileptologists could easily identify it, that is, the ILAE s syndrome of Self-limited (benign childhood) epilepsy with centrotemporal spike, whereas the ICD-9 code selected would depend on whether the child presented with seizures with or without altered consciousness, that is, Localization-related (focal) (partial) epilepsy and epileptic syndromes with complex partial seizures or Localization-related (focal) (partial) epilepsy and epileptic syndromes with simple partial seizures. Second, the ILAE classification offers much greater diagnostic specificity compared to either ICD system. The single ICD-9 code, Generalized nonconvulsive epilepsy, would be used for Childhood absence epilepsy and Juvenile absence epilepsy. Similarly the ICD-10 code, Generalized idiopathic epilepsy and epileptic syndromes, would include such disparate clinical syndromes as the ILAE s Epilepsy with generalized tonic clonic seizures alone and Juvenile myoclonic epilepsy. The 2010 ILAE classification thus has a degree of flexibility to reflect clinical practice, and it allows clinicians to define the epilepsies in the most clinically relevant manner. 6 The organizational framework cannot be linear, as seizure type does not relate in this way to syndrome or etiology. As discussed earlier, a single syndrome may have several genetic or structural etiologies, whereas the same genetic etiology may relate to different syndromes and seizure

6 353 ICD Coding for Epilepsy types. A specific example would be an infant who presents with epileptic spasms with a clinical and electroencephalography (EEG) picture defining West syndrome; magnetic resonance imaging (MRI) might confirm a structural etiology such as tuberous sclerosis complex (TSC), and a DNA test could reveal a genetic variant in the TSC1 gene. On the other hand, a person with TSC may experience only focal seizures. This nonlinear framework reflects the reality of multiple interacting genetic, structural, and environmental influences on the expression of epileptic seizures. Despite its in development status, the new classification has informed the ICD-11 coding structure for the epilepsies (see subsequent text). International Modifications of ICD-10 ICD-coded data are used internationally for a broad range of purposes including financial reasons (e.g., reimbursement of health care providers/facilities), public health (e.g., surveillance of morbidity and mortality), and research (e.g., health resource utilization and outcomes studies). 1 One of the many advantages of ICD-coded data is that the 194 member states of the WHO have agreed to its use. 7 As a result, international data can be compared between countries. However, since the release of ICD-10, a number of countries have developed their own clinical modifications (CM), such as Canada (ICD-10-CA), Australia (ICD- 10-CA), Germany (ICD-10-GM), Korea (ICD-10-KM), Thailand (ICD-10-TM), and the United States (ICD-10- CM). 1 These modifications have allowed countries to address their own national needs by adding content not yet included in the original WHO ICD-10 classification, or by providing more details at the fifth-digit levels (e.g., ICD-10- CM code G40.01 localization-related idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable and G for localization-related idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, with status epilepticus ). In general, there are no significant differences in epilepsy coding between international modifications, except in the case of countries that are adding the fifth-digit codes to define intractability or its lack. However, the definition of the main condition or principal diagnosis can vary according to the international modification. For example, the United States defines the principal diagnosis as the condition established as being primarily responsible for resulting in the episode of care in hospital, 8 10 whereas Canada adheres to the WHO definition and defines the main condition as the condition primarily responsible for the patient s need for treatment or investigation. If there is more than one such condition, the one held responsible for the greatest resources should be selected Thus, it would not be feasible to study main diagnoses in hospital discharge data, comparing Canada and the United States. The Future of ICD Coding for Epilepsy: ICD-11 and the Role of the Epilepsy Community in its Development The WHO has been working with the advice of international experts in every medical specialty on the upcoming revision of ICD-10, namely, ICD-11. 7,14,15 ICD-11 will be by far the most revolutionary update of any disease classification. For example, although several disorders such as epilepsy and headache were previously classified in the ICD-10 Episodic and paroxysmal disorders chapter, in ICD-11, they now each have their own block. 14 In creating ICD-11, the WHO named a Task Force Advisory Group (TAG) for Neurology to draw up the new codes for disorders of the nervous system. 7,16 Members of the group include representatives from the World Federation of Neurology, members chosen by the most important international neurology subspecialty organizations (e.g., the ILAE, Ettore Beghi), and members at large familiar with public health and international aspects of neurology (Donna Bergen and Marco Medina). ICD revisions are always the product of two major forces: the usefulness of stable coding for the tracking of epidemiologic statistics, and the need to reflect the latest scientific consensus about the causes and pathophysiology of disease. Given the rapid pace of scientific advances since 1992, especially in genetics and molecular biology, the WHO allowed the advisory panel unusual freedom to update the codes, even when substantial rearrangements, deletions, or additions were recommended. To support and clarify the coding choices, definitions of each item (or code) were also written by the neurology TAG, and feedback were provided by additional disease-specific consultants (e.g., Nathalie Jette), with references included whenever possible. During the 5 years of the TAG panel s deliberations, the Classification Commission of the ILAE was concurrently developing a proposal for revision of the terminology and classification of epilepsy and seizures. The general outline of the 2010 proposal was reflected in the final version drafted for the ICD-11 coding block for epilepsy and seizures. The ILAE s own publications provided definitions for epilepsy and seizure codes in ICD-11. ICD-11 Has Been Adapted to Be in Line with the New ILAE Epilepsy Classification When preparing to revise the ICD epilepsy codes for ICD-11, it became immediately evident that a compromise was needed between the structure of the most updated ILAE classification of epilepsy (an instrument focusing on the need to represent all the disease varieties to the benefit of

7 354 N. Jette et al. practicing physicians and researchers) and the revised ICD codes (structured as to preserve the WHO purpose to define the burden of the disease in terms of frequency, cause effect relationship, complications, mortality, and costs). According to the ILAE, epilepsy is considered a disease represented by the tendency for seizures to recur. 17 However, much of the seizure burden worldwide occurs in the context of acute neurologic conditions such as central nervous system (CNS) infection, inflammation, and trauma, which are not encompassed within the definition of epilepsy. 17 As such, to adequately assess the overall disease burden for the WHO comprehensively, both seizures and epilepsy must be considered. Although the ILAE requires a clear delineation between the disease (i.e., epilepsy) and its symptoms (i.e., the seizures), both should be part of differing classifications when the diagnostic process is completed; the WHO has to accept the limitations of classifying cases, due to disparities in the availability of technology and expertise in each individual country. Consequently, the WHO TAG has aligned the new ICD-11 codes with the structure of the new ILAE classification, incorporating epilepsy syndromes and etiologies but also seizure-related codes, that is, acute symptomatic seizures, status epilepticus, and seizure complications including sudden unexpected death in epilepsy (SUDEP), an entity not previously captured in earlier ICD classifications. Although ICD-11 does not retain the flexibility of the ILAE classification of the epilepsies and seizures, it reflects the etiologic perspective, with the first three coding groups representing the genetic, structural-metabolic, and unknown groups proposed in Single unprovoked or reflex seizures should be included under the epilepsies only when a minimum estimated 60% risk of seizure recurrence is anticipated. 17 If the risk is <60%, such seizures will then be coded as a single unprovoked seizure rather than epilepsy, in keeping with the new practical definition of epilepsy. 17 The Potential Impact of the New Proposed ICD-11 Epilepsy Coding System on Clinical Care, Surveillance and Public Health, and Research The hierarchical structure of the ICD-11 codes for epilepsy will facilitate coding at various levels of expertise. Primary health care providers, for example, may continue to code most patient encounters as Epilepsy, not otherwise specified, but a neurologist will easily find Epilepsy due to head trauma, whereas the epileptologist can specify Epilepsy due to GLUT1 deficiency with SLC2A1 mutation. The ICD-11 codes also reflect the syndromic epilepsy classification proposed by the ILAE Commission on Classification and Terminology, thus removing seizure type as a defining feature of a specific epilepsy. This will enhance the public health value of the classification system, since ICD-11 coding will capture the known causes of seizures and epilepsies, from neurocysticercosis and head trauma to specific genetic mutations. Conclusions ICD-coded data are used internationally for health research and public health (e.g. surveillance), to monitor and plan health services and to reimburse health providers for the care they deliver Although the quality of ICD-coded data is improving over time, the lack of a harmonized uniform classification system internationally is alarming. Many countries lag behind in incorporating the more up-to-date ICD-10 classification system. This is even more concerning with the imminent release of ICD- 11, which may not be implemented in many countries for more than a decade. The rapidity of scientific advances in the field of epilepsy and the challenges of incorporating and aligning these with existing and future ICD classifications are not negligible. The alignment of ICD-11 with the new ILAE organization of the epilepsies and seizures is promising, although it will be important to ensure that processes are in place to incorporate new epilepsy advances continuously in ICD-11 so that serious gaps in data collection do not occur. Acknowledgments Nathalie Jette holds a Canada Research Chair in Neurological Health Services Research and an Alberta Innovates Health Solutions Population Health Investigator Award. Dale C. Hesdorffer is Professor of Epidemiology at Columbia University Medical Center. Solomon L. Moshe is the Charles Frost Chair in Neurosurgery and Neurology at Einstein College of Medicine. Disclosure of Conflict of Interest Nathalie Jette is supported by operating funds from the Canadian Institutes of Health Research, Alberta Innovates Health Solutions, Alberta Health Services, Alberta Health, the University of Calgary Cumming School of Medicine, the University of Calgary Medical Group, and the Hotchkiss Brain Institute. Solomon L. Moshe is supported in part by grants RO1-NS-20253, UO1-NS045911, RO1- NS043209, and R21-NS-78333, from the National Institute of Neurological Disorders and Stroke, Department of Defense, UCB, CURE Foundation, the Heffer Family Medical Foundation, and the Segal Family Foundation. He receives from Elsevier an annual compensation for his work as Associate Editor of the journal Neurobiology of Disease and royalties from two books he co-edited. He received a consultant fee from Lundbeck and UCB. Dale C Hesdorffer is supported by grants from the Centers for Disease Control and Prevention, the National Institutes of Health, NINDS, the Epilepsy Foundation of America, Patient-Centered Outcomes Research Institute, Citizens United for Research in Epilepsy, and the Epilepsy Study Consortium. She serves as consultant at the Mount Sinai Medical Center, Injury Prevention Center, and the NYU Epilepsy Center, and serves on the advisory boards for Upsher-Smith Laboratories and Cyberonics. She receives compensation for her work as Associate Editor of Epilepsia (as does N. Jette) and royalties from Henry Stewart Talks. Ettore Beghi served on advisory boards for Viropharma and Eisai and has received grant

8 355 ICD Coding for Epilepsy funding from the European Union, the Italian Drug Agency, the Italian Ministry of Health, and UCB-Pharma. Despite the above disclosures, there are no conflicts of interest related to this particular manuscript. We confirm that we have read the Journal s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. Disclaimer This report was written by experts selected by the International League Against Epilepsy (ILAE) and was approved for publication by the ILAE. Opinions expressed by the authors, however, do not necessarily represent the policy or position of the ILAE. References 1. Jette N, Quan H, Hemmelgarn B, et al. The development, evolution, and modifications of ICD-10: challenges to the international comparability of morbidity data. Med Care 2010;48: Gersenovic M. The ICD family of classifications. Methods Inf Med 1995;34: WHO. History of the Development of the ICD. [Web site.]. Available at: Accessed December 22, Proposal for revised clinical and electroencephalographic classification of epileptic seizures. From the Commission on Classification and Terminology of the International League against Epilepsy. Epilepsia 1981;22: Proposal for revised classification of epilepsies and epileptic syndromes. Commission on Classification and Terminology of the International League against Epilepsy. Epilepsia 1989;30: Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, Epilepsia 2010;51: Mateen FJ, Dua T, Shen GC, et al. Neurological disorders in the 11th revision of the International Classification of Diseases: now open to public feedback. Lancet Neurol 2012;11: German Coding Standards. Available at: index.php/inek_site_de/g_drg_system_2008/kodierrichtlinien/ deutsche_kodierrichtlinien_2008. Accessed August 12, Draft ICD-10-CM official guidelines for coding and reporting for acute short-term and long-term hospital inpatient and physican office and other outpatient encounters Australian Coding Standards for ICD-10-AM. NSW, Australia, WHO. International statistical classification of diseases and related health problems.10th Revision. Geneva, Switzerland: WHO; ICD-10-CA. [Web site.]. Available at: disppage.jsp?cw_page=codingclass_icd10_e. Accessed December 17, Bureau of planning and strategy, Ministry of Public Health - International statistical classification of disease and related health problems, tenth revision, Thai modification. Vol. 5, Standard Coding Guidelines, 2nd Ed. Nonthaburi, Thailand: Shakir R, Rajakulendran S. The 11th revision of the International Classification of Diseases (ICD): the neurological perspective. JAMA Neurol 2013;70: Shakir R, Bergen D. International Classification of Diseases (ICD-11) and neurologic disorders: the future. Neurology 2013;81: Bergen DC, Beghi E, Medina MT. Revising the ICD-10 codes for epilepsy and seizures. Epilepsia 2012;53(Suppl. 2): Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia 2014;55: