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International Classification of Disease Coding for Obstructive Lung Disease
CHEST
Topics in Practice Management
International Classification of Disease Coding for Obstructive Lung Disease Does It Reflect Appropriate Clinical Documentation? Philip Marcus, MD, MPH, FCCP; and Sidney S. Braman, MD, FCCP
International Classification of Disease coding is widely used by physicians, hospitals, health-care payers, and governments to assess the health of populations and as a means of reimbursement for medical care based on diagnosis and severity of illness. The current classification system, International Classification of Diseases, 9th ed (ICD-9), will soon be replaced by International Classification of Diseases, 10th ed (ICD-10). When the codes that relate to COPD and asthma are examined, the clinical relevance of the categories in International Classification of Disease coding must be questioned. In the future, a more simplified terminology that is consistent with clinical usage could improve accuracy and ease of coding. At present, however, clinicians should become familiar with the present ICD-9 and future ICD-10 codes so that their descriptions of illnesses in the medical records more accurately reflect current coding terminology. CHEST 2010; 138(1):188–192 Abbreviations: ICD-9 5 International Classification of Diseases, 9th ed; ICD-9-CM 5 International Classification of Diseases, 9th ed, Clinical Modification; ICD-10 5 International Classification of Diseases, 10th ed; WHO 5 World Health Organization
International Classification of Diseases, 9th ed, TheClinical Modification (ICD-9-CM) is a medical
classification system used by all providers of health care to identify diseases and injuries in the population of the United States. Medical coders assign a numeric descriptor to medical diagnoses, procedures, surgery, signs and symptoms of disease, poisoning, adverse effects of drugs, and complications of surgery and medical care. Medical coders are employed by hospitals and other health-care facilities to support billing requirements and gather data for statistical use. They are individuals with training in medical
Manuscript received June 6, 2009; revision accepted September 15, 2009. Affiliations: From the Division of Pulmonary Medicine (Dr Marcus), St. Francis Hospital-The Heart Center, Roslyn, NY; and Division of Pulmonary and Critical Care Medicine (Dr Braman), The Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI. Correspondence to: Philip Marcus MD, MPH, FCCP, Division of Pulmonary Medicine, St. Francis Hospital-The Heart Center, 100 Port Washington Blvd, Roslyn, NY 11576; e-mail: pmarcus@ nyit.edu © 2010 American College of Chest Physicians. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestpubs.org/ site/misc/reprints.xhtml). DOI: 10.1378/chest.09-1342 188
terminology, disease processes, pharmacology, and coding techniques. Certification as a coding specialist by The American Health Information Management Association can be obtained through college-level course work, and many coders have an associates or bachelors degree in health information technology. Professional coders can also be certified by the American Association of Professional Coders. The US codes are based on a system developed by the World Health Organization (WHO) and provided in the Manual of the International Statistical Classification of Diseases, Injuries and Causes of Death, 9th Revision (see the Appendix). The US clinical modification of the WHO manual expands ICD-9 coding to offer more precise descriptors of clinical diagnoses as ICD-9-CM. The official version of codes is available from the US Government Printing Office and can be purchased from a number of commercial publishers. Coding handbooks are useful educational tools to assist in interpretation of coding regulations.1 The Centers for Medicare and Medicaid Services and the National Center for Health Statistics, two departments within the Department of Health and Human Services, issued a set of rules and instructions to be used with the official government version of ICD-9-CM. Topics in Practice Management
Downloaded from chestjournal.chestpubs.org by Kimberly Henricks on July 6, 2010 © 2010 American College of Chest Physicians
Adherence to these guidelines when assigning ICD-9-CM diagnosis and procedure codes is required under the Health Insurance Portability and Accountability Act. In addition, a reference published by the American College of Chest Physicians serves as a guide for understanding coding as it applies to pulmonary medicine from the perspective of current procedural terminology as well as ICD.2 We will address several questions, solely from the clinician’s perspective, relating to “ICD coding,” a widely used term that links clinical diagnoses to claims for medical services: How precise is the ICD-9-CM coding terminology for respiratory diseases? Are the terms used consistent with commonly used clinical descriptions of disease? Do current ICD-9-CM terms match those used in national and international disease guidelines? Perhaps most importantly, will the soonto-be implemented International Classification of Diseases, 10th ed, (ICD-10) standards have a significant impact on the coding of pulmonary disorders? To address these questions we have chosen to examine the classifications assigned to two highly prevalent respiratory diseases, COPD and asthma, and to identify how the current and future ICD classifications reflect current practice.
History of International Disease Coding The first attempts to classify diseases systematically date to the 18th century. Crude classifications were established in England, for example, to assess early childhood mortality in the population. In the 19th century, William Farr (1807-1883), one of the first medical statisticians, championed the use of improved disease classifications and advocated for greater international uniformity. The importance of a uniform classification of causes of death was finally recognized at the first International Statistical Congress held in Brussels in 1853. The International Statistical Institute, the successor to the International Statistical Congress, at its meeting in Vienna in 1891, authorized for the first time a classification of causes of death for the international community. In 1898, the American Public Health Association adopted this classification. By 1938, the Fifth International Conference for the Revision of the International List of Causes of Death was convened. The conference recognized a growing need for a list of diseases that would meet the statistical requirements of health insurance organizations, hospitals, military medical services, health administrations, and other similar bodies. However, this was not developed until the 1940s. In 1946, the WHO was entrusted with the responsibility of revising future international lists of causes of mortality and morbidity. The most recent revision was the ICD-9. It was pubwww.chestpubs.org
lished in 1977 and had input from various specialty groups who argued that the classification needed to be more relevant to actual medical care. They urged classifying conditions as they relate to the part of the body affected rather than to generalized disease states. In 1975, a joint project of the Council for International Organization of Medical Sciences and the WHO created the International Nomenclature of Diseases to provide a specific, unambiguous name for each morbid entity. The International Nomenclature of Diseases has been given preference for ICD coding. ICD-9-CM diagnosis codes are composed of codes with three, four, or five digits. Codes with three digits are included in ICD-9-CM as the heading of a category of codes that may be further subdivided. The use of fourth and/or fifth digits provides greater detail of the clinical entity. It is widely suggested that our current ICD-9-CM codes, in use for nearly 30 years, are outdated. The 10th revision conference was held by WHO in 1989, and ICD-10 was published in 1992. The United States uses this latest revision for death certificate purposes, but it is one of the few developed countries not using ICD-10 for disease classification. For the ICD-10 code sets, a final US government rule sets a compliance date of Oct. 1, 2013.3 This provides nearly 5 years of preparation time from the date of publication of the new code regulation to the date when the new code sets must be implemented. Despite the anticipated use of ICD-10 terminology, when studied for consistency in representing chart data from inpatient and outpatient records4 and overall validity of data,5 ICD-10 has not been found to perform better than ICD-9-CM. The adoption of ICD coding terminology for computerized medical record keeping has also been challenged and the use of other standard medical terminology systems has been advocated.6
ICD Coding of COPD The conditions that cause airflow obstruction and compose the general term COPD and Allied Conditions (490-496) in the ICD-9-CM coding standards include: chronic bronchitis (code 491), emphysema (code 492), chronic bronchitis with emphysema (491.2), and chronic obstructive asthma (code 493.2). The correct coding for COPD depends on the accurate identification from the medical record of the specific condition responsible for the airflow obstruction (eg, bronchitis, emphysema, or asthma). Another code used is for chronic airway obstruction, “not elsewhere classified” (code 496). It is a nonspecific code that should only be used when documentation in the medical record does not specify the type of COPD being CHEST / 138 / 1 / JULY, 2010
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treated. Hence this code cannot be used if the record specifies that chronic obstructive pulmonary disease is accompanied by the terms chronic bronchitis, emphysema, or asthma. The codes for obstructive chronic bronchitis distinguish between uncomplicated cases (without exacerbation) (code 491.20), those with an acute exacerbation (code 491.21), and those with acute bronchitis (code 491.22). An acute exacerbation is described as a worsening or decompensation of a chronic condition. An acute exacerbation is not equivalent to an infection superimposed on a chronic condition, although it is acknowledged that an exacerbation may often be triggered by an infection. The ICD coding categories for COPD, therefore, use terms that are recognizable (chronic bronchitis and emphysema), but abandoned in our current definitions of the disease. The Global Initiative for Chronic Obstructive Lung Disease guidelines7 mention that previous definitions of COPD have used the terms “emphysema” and “chronic bronchitis,” but these terms are excluded. This is also evident in the most recent American Thoracic Society/European Respiratory Society definition of COPD.8 It is argued that emphysema is a pathologic term that is often used clinically (and most often incorrectly) as the presence and extent of the destruction of gasexchanging units of the lung (alveoli). As this is not usually measured by clinicians (for example, with high-resolution chest CT scanning), the term was dropped from the definition. Chronic bronchitis, on the other hand, clinically defined as the presence of cough and sputum production for at least 3 months in each of two consecutive years, remains a clinically and epidemiologically useful term. However, it was argued by the authors of the Global Initiative for Chronic Obstructive Lung Disease that the term chronic bronchitis does not reflect the major impact of airflow limitation on morbidity and mortality in patients with COPD, and it too was eliminated. The accuracy of a diagnosis of chronic bronchitis, both self reported and physician confirmed, also has been questioned. In one longitudinal population study, patients were surveyed for self-reported chronic bronchitis or physician-diagnosed chronic bronchitis.9 The survey asked about symptoms of chronic cough and sputum production and the timing of these symptoms. Seventeen percent of current smokers, 12.4% of former smokers, and 6% of never smokers met the criteria for chronic bronchitis. The majority of people (88.4%) who reported a self- or physicianconfirmed diagnosis of chronic bronchitis did not have the correct diagnosis when standard criteria (cough and sputum as 3 months of the year for at least 2 years) were applied. Overdiagnosis of chronic bronchitis by patients and physicians, therefore, may be very common. Because the term “bronchitis” is 190
often used as a common descriptor for a nonspecific and self-limited cough, many patients assume erroneously that they have had chronic bronchitis. The terms “emphysema” and “chronic bronchitis” are used for classification of COPD in both ICD-9 and ICD-10 terminology even as they are being abandoned as descriptors by clinicians. Other terms, included as major categories or subcategories of COPD, such as chronic obstructive asthma, the terms fetid, mucopurulent, purulent, catarrhal, fibrinous, membranous, and croupous bronchitis, chronic tracheitis, and chronic tracheobronchitis are not standardized terms and not commonly used clinically. They provide a further major disconnect between healthcare providers and the medical codes. Perhaps what is needed is an alignment of ICD terminology with current international guidelines and to simplify the classification of COPD. A classification that would describe COPD in terms of severity could be useful, but at the very least, just separating stable COPD from COPD with an exacerbation could be helpful. We generally suspect infection as the cause of an exacerbation of COPD, but often just treat empirically with steroids and antibiotics. Also, the inclusion of bronchitis (490) and simple chronic bronchitis (491.0) as a category of chronic bronchitis and defined as a smokers’ cough leads to confusion.
ICD Coding of Asthma ICD coding for asthma has also been fraught with many challenges. First, the listing of asthma under the category of “Chronic Obstructive Pulmonary Disease and Allied Conditions” is incorrect, unless one subscribes to the Dutch Hypothesis, which in itself is the source of much controversy.10 National and International Guidelines for the Diagnosis and Management of Asthma define asthma as a chronic inflammatory disease of the airways and separate it from COPD.11,12 The classification of asthma in ICD-9-CM falls under category 493, and requires at least a fourth digit for subclassification. Accordingly, 493.0 refers to extrinsic asthma, 493.1 refers to intrinsic asthma, 493.2 refers to chronic obstructive asthma, and there is yet another code, 493.8 for “Other forms of asthma.” This is further divided into 493.81 for exercise-induced bronchospasm and 493.82 for cough variant asthma. For codes 493.0-493.2, a fifth digit is required. This may be a 0, representing unspecified, a 1 for “with status asthmaticus,” or a 2 for “with (acute) exacerbation.” Once again, as with the coding for COPD, the terminology used for asthma is both familiar (viz, extrinsic and intrinsic), and confusing (eg, status asthmaticus as compared with an acute exacerbation), and the inclusion of chronic obstructive asthma as a separate entity. Topics in Practice Management
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The classification in ICD-9-CM ignores the concepts of asthma severity and control, in contrast to all published guidelines, and focuses on terms that have largely been abandoned. It has been established that . 60% of asthma is related to allergic factors, a number even higher in children, and that many patients with asthma have not been investigated for these extrinsic factors.13 Also, extrinsic asthma (493.0) is defined in ICD as synonymous with childhood asthma and intrinsic asthma (493.1) defined as late-onset asthma. In addition, status asthmaticus is defined as a severe intractable episode of asthma unresponsive to normal therapeutic measures. It might be more helpful to categorize asthma in terms of severity using the terminology of intermittent vs persistent and control, incorporating the categories of wellcontrolled, not well-controlled, very poorly controlled asthma. The category of “chronic obstructive asthma,” 493.2, is defined as chronic asthmatic bronchitis; is this not just another way of saying persistent asthma?
ICD-10 As already noted, ICD-10 will be mandated for use by 2013. The categories for chronic lower respiratory diseases have already been finalized and are similar to those in ICD-9. However, the number system is completely different and falls under codes J40-J47. The terminology of chronic bronchitis (J41 and J42) and emphysema (J43) persist as in ICD-9, but with slightly different subclasses. There is now an additional category of “Other chronic obstructive pulmonary disease,” J44, which excludes emphysema and chronic bronchitis, but does make an attempt to differentiate exacerbations (J44.1) from what we presume is stable disease. This is analogous to the category of 496, “Chronic airway obstruction, not elsewhere classified,” and is often used as an easy way out, adding nothing to the value of such coding. However, the inclusion of detailed forms of emphysema (viz, panlobular, centrilobular, interstitial, and compensatory) is not likely applicable to clinical practice. Asthma has its own category (J45), but is still subdivided into J45.0 (predominantly allergic), J45.1 (nonallergic), J45.8 (mixed), and J45.9 (unspecified, including late-onset). In addition, there is now a separate code for status asthmaticus, defined as acute severe asthma, J46.
Conclusion There is clearly a need for classification of diseases in order to study trends in mortality as well as to understand the incidence and prevalence of conditions commonly and uncommonly encountered. The claswww.chestpubs.org
sification used should be clinically relevant and should also be uniform in order to allow comparisons within regions and countries throughout the world. When the classification of obstructive lung diseases is studied, there is a disconnect in medical terminology between what is published in ICD and what clinicians commonly use based on national and international guidelines. We have learned a great deal about the pathogenesis and natural history of asthma and COPD in the past 30 years, and yet the documentation of these diagnoses is based on an old classification that does not reflect current clinical practice. Although there are reports showing that ICD-9 coding can be very accurate in some specific instances, such as with the emergency care of COPD exacerbations and with acute respiratory illness,14,15 the sensitivity of detecting disease may be less than 50%15 and ICD coding of hospital admissions for COPD are often inaccurate.16 In one study, discharge summaries were reviewed for errors in coding for COPD admissions and the recoding led to a change in the primary diagnosis in 16% of the patient stays and an additional secondary diagnosis in 18% of hospital stays.16 We would hope that future versions of ICD would simplify classifications and show consistency with clinical practice, rather than mixing pathologic and clinical terms that cannot be accurately applied. In doing so, this should lead to more scientifically accurate and clinically meaningful analysis of data obtained from medical records and claims data. Errors do occur in coding procedures because coders lack sufficient knowledge in a specific area (different steps of the coding process require different levels of knowledge) and because there is internal inconsistency of the ICD.16 This could be improved with a more simplified terminology that is more consistent with clinical usage. In addition, since a major reason for errors of coding is physicians’ errors in primary documentation,16,17 it would be useful if clinicians became more familiar with ICD terminology so that the descriptions used in medical records can more efficiently direct the work of medical coders. Appendix Current International Classification of Diseases, 9th Ed (ICD-9) Classification of Obstructive Lung Diseases Asthma (493) The following fifth-digit subclassification is for use with codes 493.0-493.2 and 493.9: 0 5 unspecified 1 5 with status asthmaticus 2 5 with (acute) exacerbation CHEST / 138 / 1 / JULY, 2010
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493.0 Extrinsic asthma 493.1 Intrinsic asthma 493.2 Chronic obstructive asthma Includes asthma with COPD and chronic asthmatic bronchitis 493.8 Other forms of asthma 493.81 Exercise-induced bronchospasm 493.82 Cough-variant asthma 493.9 Asthma, unspecified COPD (491, 492, 496) 491 Chronic Bronchitis 491.0 Simple chronic bronchitis 491.1 Mucopurulent chronic bronchitis 491.2 Obstructive chronic bronchitis Bronchitis: emphysematous, obstructive Bronchitis with: chronic airway obstruction, emphysema 491.20 Without exacerbation Emphysema with chronic bronchitis 491.21 With (acute) exacerbation Acute exacerbation of COPD Decompensated COPD Decompensated COPD with exacerbation 491.22 With acute bronchitis 492 Emphysema 492.0 Emphysematous bleb 492.8 Other emphysema* Emphysema Centriacinar Centrilobular Obstructive Panacinar Panlobular MacLeod syndrome Swyer-James syndrome *Excludes emphysema with chronic bronchitis, compensatory emphysema 496 Chronic airway obstruction, not elsewhere classified Chronic: nonspecific lung disease, obstructive lung disease, obstructive pulmonary disease Excludes COPD, specified, as with bronchitis, emphysema or both This compilation was taken from the published ICD-9 and modified slightly so as to be less comprehensive.
Acknowledgments Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
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References 1. Brown F. ICD-9 CM Coding Handbook. Chicago, IL: American Hospital Association; 2009. 2. Manaker S, Krier-Morrow D, Pohlig C, eds. Coding for Chest Medicine 2009. Northbrook, IL: American College of Chest Physicians; 2008:1-436. 3. Office of the Secretary, HHS. HIPAA administrative simplification: modification to medical data code set standards to adopt ICD-10-CM and ICD-10-PCS. Proposed rule. Fed Regist. 2008;73(164):49795-49832. 4. Chute CG, Cohn SP, Campbell KE, Oliver DE, Campbell JR. The content coverage of clinical classifications. For The Computer-Based Patient Record Institute’s Work Group on Codes & Structures. J Am Med Inform Assoc. 1996;3(3):224-233. 5. Quan H, Li B, Saunders LD, et al; IMECCHI Investigators. Assessing validity of ICD-9-CM and ICD-10 administrative data in recording clinical conditions in a unique dually coded database. Health Serv Res. 2008;43(4):1424-1441. 6. Cimino JJ. Vocabulary and health care information technology: state of the art. J Am Soc Inf Sci. 1999;46:777-782. 7. Rabe KF, Hurd S, Anzueto A, et al; Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary. Am J Respir Crit Care Med. 2007;176(6):532-555. 8. Celli BR, MacNee W, Agusti A, et al; ATS/ERS Task Force. Standards for the diagnosis and treatment of patients with COPD: a summary of the ATS/ERS position paper. Eur Respir J. 2004;23(6):932-946. 9. Bobadilla A, Guerra S, Sherrill D, Barbee R. How accurate is the self-reported diagnosis of chronic bronchitis? Chest. 2002;122(4):1234-1239. 10. Barnes PJ. Against the Dutch hypothesis: asthma and chronic obstructive pulmonary disease are distinct diseases. Am J Respir Crit Care Med. 2006;174(3):240-243., discussion 243-244. 11 . Guidelines for the Diagnosis and Management of Asthma (EPR-3). http://www.nhlbi.nih.gov/guidelines/asthma. Accessed November 2009. 12. GINA Report, Global Strategy for Asthma Management and Prevention. http://www.ginasthma.com. Accessed November 2009. 13. Milgrom H. Understanding allergic asthma. www.aaaai.org/ patients/allergic_asthma/qanda.stm. Accessed May 24, 2007. 14. Ginde AA, Tsai CL, Blanc PG, Camargo CA Jr. Positive predictive value of ICD-9-CM codes to detect acute exacerbation of COPD in the emergency department. Jt Comm J Qual Patient Saf. 2008;34(11):678-680. 15. Espina JU, Wagner MM. Accuracy of ICD-9-coded chief complaints and diagnoses for the detection of acute respiratory illness. Proc AMIA Symp. 2001:164-8 16. Stavem K, Bjerke G, Kjelsberg FN, Ruud EA, Saxrud SO. Coding of diagnoses in chronic obstructive pulmonary disease—economic consequences [In Norwegian]. Tidsskr Nor Laegeforen. 2002;122(23):2290-2293. 17. Surján G. Questions on validity of International Classification of Diseases-coded diagnoses. Int J Med Inform. 1999;54(2): 77-95.
Topics in Practice Management
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Topics in Practice Management
International Classification of Disease Coding for Obstructive Lung Disease Does It Reflect Appropriate Clinical Documentation? Philip Marcus, MD, MPH, FCCP; and Sidney S. Braman, MD, FCCP
International Classification of Disease coding is widely used by physicians, hospitals, health-care payers, and governments to assess the health of populations and as a means of reimbursement for medical care based on diagnosis and severity of illness. The current classification system, International Classification of Diseases, 9th ed (ICD-9), will soon be replaced by International Classification of Diseases, 10th ed (ICD-10). When the codes that relate to COPD and asthma are examined, the clinical relevance of the categories in International Classification of Disease coding must be questioned. In the future, a more simplified terminology that is consistent with clinical usage could improve accuracy and ease of coding. At present, however, clinicians should become familiar with the present ICD-9 and future ICD-10 codes so that their descriptions of illnesses in the medical records more accurately reflect current coding terminology. CHEST 2010; 138(1):188–192 Abbreviations: ICD-9 5 International Classification of Diseases, 9th ed; ICD-9-CM 5 International Classification of Diseases, 9th ed, Clinical Modification; ICD-10 5 International Classification of Diseases, 10th ed; WHO 5 World Health Organization
International Classification of Diseases, 9th ed, TheClinical Modification (ICD-9-CM) is a medical
classification system used by all providers of health care to identify diseases and injuries in the population of the United States. Medical coders assign a numeric descriptor to medical diagnoses, procedures, surgery, signs and symptoms of disease, poisoning, adverse effects of drugs, and complications of surgery and medical care. Medical coders are employed by hospitals and other health-care facilities to support billing requirements and gather data for statistical use. They are individuals with training in medical
Manuscript received June 6, 2009; revision accepted September 15, 2009. Affiliations: From the Division of Pulmonary Medicine (Dr Marcus), St. Francis Hospital-The Heart Center, Roslyn, NY; and Division of Pulmonary and Critical Care Medicine (Dr Braman), The Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI. Correspondence to: Philip Marcus MD, MPH, FCCP, Division of Pulmonary Medicine, St. Francis Hospital-The Heart Center, 100 Port Washington Blvd, Roslyn, NY 11576; e-mail: pmarcus@ nyit.edu © 2010 American College of Chest Physicians. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestpubs.org/ site/misc/reprints.xhtml). DOI: 10.1378/chest.09-1342 188
terminology, disease processes, pharmacology, and coding techniques. Certification as a coding specialist by The American Health Information Management Association can be obtained through college-level course work, and many coders have an associates or bachelors degree in health information technology. Professional coders can also be certified by the American Association of Professional Coders. The US codes are based on a system developed by the World Health Organization (WHO) and provided in the Manual of the International Statistical Classification of Diseases, Injuries and Causes of Death, 9th Revision (see the Appendix). The US clinical modification of the WHO manual expands ICD-9 coding to offer more precise descriptors of clinical diagnoses as ICD-9-CM. The official version of codes is available from the US Government Printing Office and can be purchased from a number of commercial publishers. Coding handbooks are useful educational tools to assist in interpretation of coding regulations.1 The Centers for Medicare and Medicaid Services and the National Center for Health Statistics, two departments within the Department of Health and Human Services, issued a set of rules and instructions to be used with the official government version of ICD-9-CM. Topics in Practice Management
Downloaded from chestjournal.chestpubs.org by Kimberly Henricks on July 6, 2010 © 2010 American College of Chest Physicians
Adherence to these guidelines when assigning ICD-9-CM diagnosis and procedure codes is required under the Health Insurance Portability and Accountability Act. In addition, a reference published by the American College of Chest Physicians serves as a guide for understanding coding as it applies to pulmonary medicine from the perspective of current procedural terminology as well as ICD.2 We will address several questions, solely from the clinician’s perspective, relating to “ICD coding,” a widely used term that links clinical diagnoses to claims for medical services: How precise is the ICD-9-CM coding terminology for respiratory diseases? Are the terms used consistent with commonly used clinical descriptions of disease? Do current ICD-9-CM terms match those used in national and international disease guidelines? Perhaps most importantly, will the soonto-be implemented International Classification of Diseases, 10th ed, (ICD-10) standards have a significant impact on the coding of pulmonary disorders? To address these questions we have chosen to examine the classifications assigned to two highly prevalent respiratory diseases, COPD and asthma, and to identify how the current and future ICD classifications reflect current practice.
History of International Disease Coding The first attempts to classify diseases systematically date to the 18th century. Crude classifications were established in England, for example, to assess early childhood mortality in the population. In the 19th century, William Farr (1807-1883), one of the first medical statisticians, championed the use of improved disease classifications and advocated for greater international uniformity. The importance of a uniform classification of causes of death was finally recognized at the first International Statistical Congress held in Brussels in 1853. The International Statistical Institute, the successor to the International Statistical Congress, at its meeting in Vienna in 1891, authorized for the first time a classification of causes of death for the international community. In 1898, the American Public Health Association adopted this classification. By 1938, the Fifth International Conference for the Revision of the International List of Causes of Death was convened. The conference recognized a growing need for a list of diseases that would meet the statistical requirements of health insurance organizations, hospitals, military medical services, health administrations, and other similar bodies. However, this was not developed until the 1940s. In 1946, the WHO was entrusted with the responsibility of revising future international lists of causes of mortality and morbidity. The most recent revision was the ICD-9. It was pubwww.chestpubs.org
lished in 1977 and had input from various specialty groups who argued that the classification needed to be more relevant to actual medical care. They urged classifying conditions as they relate to the part of the body affected rather than to generalized disease states. In 1975, a joint project of the Council for International Organization of Medical Sciences and the WHO created the International Nomenclature of Diseases to provide a specific, unambiguous name for each morbid entity. The International Nomenclature of Diseases has been given preference for ICD coding. ICD-9-CM diagnosis codes are composed of codes with three, four, or five digits. Codes with three digits are included in ICD-9-CM as the heading of a category of codes that may be further subdivided. The use of fourth and/or fifth digits provides greater detail of the clinical entity. It is widely suggested that our current ICD-9-CM codes, in use for nearly 30 years, are outdated. The 10th revision conference was held by WHO in 1989, and ICD-10 was published in 1992. The United States uses this latest revision for death certificate purposes, but it is one of the few developed countries not using ICD-10 for disease classification. For the ICD-10 code sets, a final US government rule sets a compliance date of Oct. 1, 2013.3 This provides nearly 5 years of preparation time from the date of publication of the new code regulation to the date when the new code sets must be implemented. Despite the anticipated use of ICD-10 terminology, when studied for consistency in representing chart data from inpatient and outpatient records4 and overall validity of data,5 ICD-10 has not been found to perform better than ICD-9-CM. The adoption of ICD coding terminology for computerized medical record keeping has also been challenged and the use of other standard medical terminology systems has been advocated.6
ICD Coding of COPD The conditions that cause airflow obstruction and compose the general term COPD and Allied Conditions (490-496) in the ICD-9-CM coding standards include: chronic bronchitis (code 491), emphysema (code 492), chronic bronchitis with emphysema (491.2), and chronic obstructive asthma (code 493.2). The correct coding for COPD depends on the accurate identification from the medical record of the specific condition responsible for the airflow obstruction (eg, bronchitis, emphysema, or asthma). Another code used is for chronic airway obstruction, “not elsewhere classified” (code 496). It is a nonspecific code that should only be used when documentation in the medical record does not specify the type of COPD being CHEST / 138 / 1 / JULY, 2010
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treated. Hence this code cannot be used if the record specifies that chronic obstructive pulmonary disease is accompanied by the terms chronic bronchitis, emphysema, or asthma. The codes for obstructive chronic bronchitis distinguish between uncomplicated cases (without exacerbation) (code 491.20), those with an acute exacerbation (code 491.21), and those with acute bronchitis (code 491.22). An acute exacerbation is described as a worsening or decompensation of a chronic condition. An acute exacerbation is not equivalent to an infection superimposed on a chronic condition, although it is acknowledged that an exacerbation may often be triggered by an infection. The ICD coding categories for COPD, therefore, use terms that are recognizable (chronic bronchitis and emphysema), but abandoned in our current definitions of the disease. The Global Initiative for Chronic Obstructive Lung Disease guidelines7 mention that previous definitions of COPD have used the terms “emphysema” and “chronic bronchitis,” but these terms are excluded. This is also evident in the most recent American Thoracic Society/European Respiratory Society definition of COPD.8 It is argued that emphysema is a pathologic term that is often used clinically (and most often incorrectly) as the presence and extent of the destruction of gasexchanging units of the lung (alveoli). As this is not usually measured by clinicians (for example, with high-resolution chest CT scanning), the term was dropped from the definition. Chronic bronchitis, on the other hand, clinically defined as the presence of cough and sputum production for at least 3 months in each of two consecutive years, remains a clinically and epidemiologically useful term. However, it was argued by the authors of the Global Initiative for Chronic Obstructive Lung Disease that the term chronic bronchitis does not reflect the major impact of airflow limitation on morbidity and mortality in patients with COPD, and it too was eliminated. The accuracy of a diagnosis of chronic bronchitis, both self reported and physician confirmed, also has been questioned. In one longitudinal population study, patients were surveyed for self-reported chronic bronchitis or physician-diagnosed chronic bronchitis.9 The survey asked about symptoms of chronic cough and sputum production and the timing of these symptoms. Seventeen percent of current smokers, 12.4% of former smokers, and 6% of never smokers met the criteria for chronic bronchitis. The majority of people (88.4%) who reported a self- or physicianconfirmed diagnosis of chronic bronchitis did not have the correct diagnosis when standard criteria (cough and sputum as 3 months of the year for at least 2 years) were applied. Overdiagnosis of chronic bronchitis by patients and physicians, therefore, may be very common. Because the term “bronchitis” is 190
often used as a common descriptor for a nonspecific and self-limited cough, many patients assume erroneously that they have had chronic bronchitis. The terms “emphysema” and “chronic bronchitis” are used for classification of COPD in both ICD-9 and ICD-10 terminology even as they are being abandoned as descriptors by clinicians. Other terms, included as major categories or subcategories of COPD, such as chronic obstructive asthma, the terms fetid, mucopurulent, purulent, catarrhal, fibrinous, membranous, and croupous bronchitis, chronic tracheitis, and chronic tracheobronchitis are not standardized terms and not commonly used clinically. They provide a further major disconnect between healthcare providers and the medical codes. Perhaps what is needed is an alignment of ICD terminology with current international guidelines and to simplify the classification of COPD. A classification that would describe COPD in terms of severity could be useful, but at the very least, just separating stable COPD from COPD with an exacerbation could be helpful. We generally suspect infection as the cause of an exacerbation of COPD, but often just treat empirically with steroids and antibiotics. Also, the inclusion of bronchitis (490) and simple chronic bronchitis (491.0) as a category of chronic bronchitis and defined as a smokers’ cough leads to confusion.
ICD Coding of Asthma ICD coding for asthma has also been fraught with many challenges. First, the listing of asthma under the category of “Chronic Obstructive Pulmonary Disease and Allied Conditions” is incorrect, unless one subscribes to the Dutch Hypothesis, which in itself is the source of much controversy.10 National and International Guidelines for the Diagnosis and Management of Asthma define asthma as a chronic inflammatory disease of the airways and separate it from COPD.11,12 The classification of asthma in ICD-9-CM falls under category 493, and requires at least a fourth digit for subclassification. Accordingly, 493.0 refers to extrinsic asthma, 493.1 refers to intrinsic asthma, 493.2 refers to chronic obstructive asthma, and there is yet another code, 493.8 for “Other forms of asthma.” This is further divided into 493.81 for exercise-induced bronchospasm and 493.82 for cough variant asthma. For codes 493.0-493.2, a fifth digit is required. This may be a 0, representing unspecified, a 1 for “with status asthmaticus,” or a 2 for “with (acute) exacerbation.” Once again, as with the coding for COPD, the terminology used for asthma is both familiar (viz, extrinsic and intrinsic), and confusing (eg, status asthmaticus as compared with an acute exacerbation), and the inclusion of chronic obstructive asthma as a separate entity. Topics in Practice Management
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The classification in ICD-9-CM ignores the concepts of asthma severity and control, in contrast to all published guidelines, and focuses on terms that have largely been abandoned. It has been established that . 60% of asthma is related to allergic factors, a number even higher in children, and that many patients with asthma have not been investigated for these extrinsic factors.13 Also, extrinsic asthma (493.0) is defined in ICD as synonymous with childhood asthma and intrinsic asthma (493.1) defined as late-onset asthma. In addition, status asthmaticus is defined as a severe intractable episode of asthma unresponsive to normal therapeutic measures. It might be more helpful to categorize asthma in terms of severity using the terminology of intermittent vs persistent and control, incorporating the categories of wellcontrolled, not well-controlled, very poorly controlled asthma. The category of “chronic obstructive asthma,” 493.2, is defined as chronic asthmatic bronchitis; is this not just another way of saying persistent asthma?
ICD-10 As already noted, ICD-10 will be mandated for use by 2013. The categories for chronic lower respiratory diseases have already been finalized and are similar to those in ICD-9. However, the number system is completely different and falls under codes J40-J47. The terminology of chronic bronchitis (J41 and J42) and emphysema (J43) persist as in ICD-9, but with slightly different subclasses. There is now an additional category of “Other chronic obstructive pulmonary disease,” J44, which excludes emphysema and chronic bronchitis, but does make an attempt to differentiate exacerbations (J44.1) from what we presume is stable disease. This is analogous to the category of 496, “Chronic airway obstruction, not elsewhere classified,” and is often used as an easy way out, adding nothing to the value of such coding. However, the inclusion of detailed forms of emphysema (viz, panlobular, centrilobular, interstitial, and compensatory) is not likely applicable to clinical practice. Asthma has its own category (J45), but is still subdivided into J45.0 (predominantly allergic), J45.1 (nonallergic), J45.8 (mixed), and J45.9 (unspecified, including late-onset). In addition, there is now a separate code for status asthmaticus, defined as acute severe asthma, J46.
Conclusion There is clearly a need for classification of diseases in order to study trends in mortality as well as to understand the incidence and prevalence of conditions commonly and uncommonly encountered. The claswww.chestpubs.org
sification used should be clinically relevant and should also be uniform in order to allow comparisons within regions and countries throughout the world. When the classification of obstructive lung diseases is studied, there is a disconnect in medical terminology between what is published in ICD and what clinicians commonly use based on national and international guidelines. We have learned a great deal about the pathogenesis and natural history of asthma and COPD in the past 30 years, and yet the documentation of these diagnoses is based on an old classification that does not reflect current clinical practice. Although there are reports showing that ICD-9 coding can be very accurate in some specific instances, such as with the emergency care of COPD exacerbations and with acute respiratory illness,14,15 the sensitivity of detecting disease may be less than 50%15 and ICD coding of hospital admissions for COPD are often inaccurate.16 In one study, discharge summaries were reviewed for errors in coding for COPD admissions and the recoding led to a change in the primary diagnosis in 16% of the patient stays and an additional secondary diagnosis in 18% of hospital stays.16 We would hope that future versions of ICD would simplify classifications and show consistency with clinical practice, rather than mixing pathologic and clinical terms that cannot be accurately applied. In doing so, this should lead to more scientifically accurate and clinically meaningful analysis of data obtained from medical records and claims data. Errors do occur in coding procedures because coders lack sufficient knowledge in a specific area (different steps of the coding process require different levels of knowledge) and because there is internal inconsistency of the ICD.16 This could be improved with a more simplified terminology that is more consistent with clinical usage. In addition, since a major reason for errors of coding is physicians’ errors in primary documentation,16,17 it would be useful if clinicians became more familiar with ICD terminology so that the descriptions used in medical records can more efficiently direct the work of medical coders. Appendix Current International Classification of Diseases, 9th Ed (ICD-9) Classification of Obstructive Lung Diseases Asthma (493) The following fifth-digit subclassification is for use with codes 493.0-493.2 and 493.9: 0 5 unspecified 1 5 with status asthmaticus 2 5 with (acute) exacerbation CHEST / 138 / 1 / JULY, 2010
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493.0 Extrinsic asthma 493.1 Intrinsic asthma 493.2 Chronic obstructive asthma Includes asthma with COPD and chronic asthmatic bronchitis 493.8 Other forms of asthma 493.81 Exercise-induced bronchospasm 493.82 Cough-variant asthma 493.9 Asthma, unspecified COPD (491, 492, 496) 491 Chronic Bronchitis 491.0 Simple chronic bronchitis 491.1 Mucopurulent chronic bronchitis 491.2 Obstructive chronic bronchitis Bronchitis: emphysematous, obstructive Bronchitis with: chronic airway obstruction, emphysema 491.20 Without exacerbation Emphysema with chronic bronchitis 491.21 With (acute) exacerbation Acute exacerbation of COPD Decompensated COPD Decompensated COPD with exacerbation 491.22 With acute bronchitis 492 Emphysema 492.0 Emphysematous bleb 492.8 Other emphysema* Emphysema Centriacinar Centrilobular Obstructive Panacinar Panlobular MacLeod syndrome Swyer-James syndrome *Excludes emphysema with chronic bronchitis, compensatory emphysema 496 Chronic airway obstruction, not elsewhere classified Chronic: nonspecific lung disease, obstructive lung disease, obstructive pulmonary disease Excludes COPD, specified, as with bronchitis, emphysema or both This compilation was taken from the published ICD-9 and modified slightly so as to be less comprehensive.
Acknowledgments Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
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References 1. Brown F. ICD-9 CM Coding Handbook. Chicago, IL: American Hospital Association; 2009. 2. Manaker S, Krier-Morrow D, Pohlig C, eds. Coding for Chest Medicine 2009. Northbrook, IL: American College of Chest Physicians; 2008:1-436. 3. Office of the Secretary, HHS. HIPAA administrative simplification: modification to medical data code set standards to adopt ICD-10-CM and ICD-10-PCS. Proposed rule. Fed Regist. 2008;73(164):49795-49832. 4. Chute CG, Cohn SP, Campbell KE, Oliver DE, Campbell JR. The content coverage of clinical classifications. For The Computer-Based Patient Record Institute’s Work Group on Codes & Structures. J Am Med Inform Assoc. 1996;3(3):224-233. 5. Quan H, Li B, Saunders LD, et al; IMECCHI Investigators. Assessing validity of ICD-9-CM and ICD-10 administrative data in recording clinical conditions in a unique dually coded database. Health Serv Res. 2008;43(4):1424-1441. 6. Cimino JJ. Vocabulary and health care information technology: state of the art. J Am Soc Inf Sci. 1999;46:777-782. 7. Rabe KF, Hurd S, Anzueto A, et al; Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary. Am J Respir Crit Care Med. 2007;176(6):532-555. 8. Celli BR, MacNee W, Agusti A, et al; ATS/ERS Task Force. Standards for the diagnosis and treatment of patients with COPD: a summary of the ATS/ERS position paper. Eur Respir J. 2004;23(6):932-946. 9. Bobadilla A, Guerra S, Sherrill D, Barbee R. How accurate is the self-reported diagnosis of chronic bronchitis? Chest. 2002;122(4):1234-1239. 10. Barnes PJ. Against the Dutch hypothesis: asthma and chronic obstructive pulmonary disease are distinct diseases. Am J Respir Crit Care Med. 2006;174(3):240-243., discussion 243-244. 11 . Guidelines for the Diagnosis and Management of Asthma (EPR-3). http://www.nhlbi.nih.gov/guidelines/asthma. Accessed November 2009. 12. GINA Report, Global Strategy for Asthma Management and Prevention. http://www.ginasthma.com. Accessed November 2009. 13. Milgrom H. Understanding allergic asthma. www.aaaai.org/ patients/allergic_asthma/qanda.stm. Accessed May 24, 2007. 14. Ginde AA, Tsai CL, Blanc PG, Camargo CA Jr. Positive predictive value of ICD-9-CM codes to detect acute exacerbation of COPD in the emergency department. Jt Comm J Qual Patient Saf. 2008;34(11):678-680. 15. Espina JU, Wagner MM. Accuracy of ICD-9-coded chief complaints and diagnoses for the detection of acute respiratory illness. Proc AMIA Symp. 2001:164-8 16. Stavem K, Bjerke G, Kjelsberg FN, Ruud EA, Saxrud SO. Coding of diagnoses in chronic obstructive pulmonary disease—economic consequences [In Norwegian]. Tidsskr Nor Laegeforen. 2002;122(23):2290-2293. 17. Surján G. Questions on validity of International Classification of Diseases-coded diagnoses. Int J Med Inform. 1999;54(2): 77-95.
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