Chronic Condition Indicator ICD-9-CM codes were frozen in preparation for ICD-10 implementation and regular maintenance of the codes has been suspended. The HCUP Tools for ICD-9-CM should only be used with data for discharges before 10/1/2015.
The Chronic Condition Indicator is one in a family of databases and software tools developed as part of the Healthcare Cost and Utilization Project (HCUP), a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality. HCUP databases, tools, and software inform decision making at the national, State, and community levels. Contents:
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The Chronic Condition Indicator provides an easy way for users to categorize ICD-9-CM diagnosis codes into one of two categories: chronic or not chronic. Examples of chronic conditions include conditions such as malignancies, diabetes, most forms of mental illness, hypertension, many forms of heart disease, and congenital anomalies. Non-chronic conditions include conditions such as infections, pregnancy, many neonatal conditions, non-specific symptoms, and injuries. To obtain the entire listing of all conditions view the downloadable file which contains a listing of all ICD-9-CM codes and their assignment to chronic or nonchronic.
Diagnosis codes for this tool are based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM), Fifth Edition. The ICD-9-CM consists of approximately 14,000 diagnosis codes. This documentation provides an overview of the following:
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The Chronic Condition Indicator is created to facilitate health services research on diagnoses using administrative data. This classification system allows researchers to readily determine if a diagnosis is a chronic condition. In addition, the tool groups all diagnoses into body systems so that users can create indicators listing which specific body systems are affected by a chronic condition listed on the record.
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The Chronic Condition Indicator categorizes all ICD-9-CM diagnosis codes as chronic or not chronic. A chronic condition is defined as a condition that lasts 12 months or longer and meets one or both of the following tests: (a) it places limitations on self-care, independent living, and social interactions; (b) it results in the need for ongoing intervention with medical products, services, and special equipment (see Perrin et al., 1993). The identification of chronic conditions is based on all 5-digit ICD-9-CM codes. E Codes, or external cause of injury codes, are not classified, because all injuries are assumed to be acute.
The algorithm originated with work reported by Hwang et al (2001) in which selected 3-digit ICD-9-CM codes were classified as chronic conditions. That study employed diagnosis information from the Medical Expenditure Panel Survey (MEPS), which is based on patient self-report and thus lacks the specificity of physician-assigned diagnoses. For Hwang’s study, a physician panel reviewed each diagnosis code that appeared in MEPS data and determined whether the code represented an acute or chronic condition. Hwang’s method was enhanced for the inpatient data in this study because a large number of conditions had not been coded in MEPS data and thus were not classified as acute or chronic. In addition, a number of ICD-9-CM codes at the 3-digit level had been designated as acute even though they may subsume more specific constituent 5-digit codes of chronic conditions. Thus, each 5-digit code was reviewed by a health services researcher with a clinical background using Hwang’s classification as well as other sources that provided information on the chronicity of specific conditions (Burwell et al, 1997; Elixhauser et al, 1998; Ozminkowski et al, 2000; University of Manitoba, 2000; Wisconsin, 2004). Disagreements with Hwang’s original classification were resolved in consultation with one of the original physician panel members. As a final step, the assignment of all ICD-9-CM codes was reviewed by an expert medical coder, resulting in the reassignment of some codes. In general, Hwang's designation of chronic (1) versus not chronic (0) superceded other references. However, there were a number of exceptions:
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One file is necessary to assign the Chronic Condition Indicator and to assign ICD-9-CM codes into body systems. This file is provided as an ASCII (DOS text) file. The file can be applied to designate ICD-9-CM diagnosis codes as chronic or non-chronic, or to assign a body system. The tool includes four elements: ICD-9-CM diagnosis codes, ICD-9-CM code labels, Chronic/non-Chronic assignments, and Body System assignments.
The contents of the file are described below:
The chronic indicator is defined as either 0 - non-chronic condition or 1 - chronic condition. The body system indicator is divided into the following categories: 1 = Infectious and parasitic disease 2 = Neoplasms 3 = Endocrine, nutritional, and metabolic diseases and immunity disorders 4 = Diseases of blood and blood-forming organs 5 = Mental disorders 6 = Diseases of the nervous system and sense organs 7 = Diseases of the circulatory system 8 = Diseases of the respiratory system 9 = Diseases of the digestive system 10 = Diseases of the genitourinary system 11 = Complications of pregnancy, childbirth, and the puerperium 12 = Diseases of the skin and subcutaneous tissue 13 = Diseases of the musculoskeletal system 14 = Congenital anomalies 15 = Certain conditions originating in the perinatal period 16 = Symptoms, signs, and ill-defined conditions 17 = Injury and poisoning 18 = Factors influencing health status and contact with health services | ||||||||||||
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The ICD-9-CM codes are revised every October. New codes are added, existing codes are deleted, and definitions of current codes are changed. The four categories are revised annually, in response to ICD-9-CM changes. There were no new diagnosis codes for 2015. Using the current Chronic Condition Indicator files with data outside this time period may result in misclassification of ICD-9-CM codes.
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In practice, ICD-9-CM diagnosis codes are represented by 3-, 4-, or 5-character codes with explicit decimals. In the downloadable translation files, ICD-9-CM diagnoses are represented as 5-character alphanumeric codes with implicit decimals. These alphanumeric codes are enclosed in quotation marks in the translation files. Examples are presented below:
To assure that diagnosis codes are properly processed in the Chronic Condition Indicator, the following actions must be taken:
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The Chronic Condition Indicator translation file lists the ICD-9-CM diagnosis codes and their corresponding chronic/non-chronic designation. The file also lists the body type associated with each diagnosis, chronic and not chronic. This CSV file can be viewed in a text editor or by using Microsoft Excel. The manner in which this file may be applied varies by the type of software package. For example, in SAS, the files can be used to create a format through the command PROC FORMAT, which translates ICD-9-CM diagnosis codes into the Chronic Condition Indicator/body type. In SPSS, the translations can be adapted through the use of COMPUTE and VALUE LABELS statements or a series of RECODES. Sample Stata programs are provided below.
Calculating NCHRONIC: Users who wish to determine the number of chronic conditions on a discharge will need to do the following:
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The translation file for use with SAS or SPSS is an ASCII (DOS text) file and is available for download as CCI2015.CSV.
Stata Chronic Condition Indicator Program (ZIP file, 10 KB) | ||||||||||||
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Chi MJ, Lee CY, Wu SC. The prevalence of chronic conditions and medical expenditures of the elderly by chronic condition indicator (CCI). Archives of gerontology and geriatrics, Epub ahead of print, May 10, 2010. http://www.ncbi.nlm.nih.gov/pubmed/20452688.
Friedman B, Jiang HJ, Elixhauser A, Segal A. 2006. "Hospital costs for adults with multiple chronic conditions." Medical Care Research and Review 63(3): 327-346. | ||||||||||||
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Magnan, Elizabeth. Algorithm for Identifying Patients with Multiple Chronic Conditions (Multimorbidity).http://www.hipxchange.org/comorbidities
![]() Burwell B, Crown W, Drabek J. (1997). "Children with Severe Chronic Conditions on Medicaid," Report prepared under contract, U.S. Department of Health and Human Services, Office of the Assistant Secretary for Planning and Evaluation (ASPE), Office of Disability, Aging, and Long-Term Care Policy. Report available at Web site http://aspe.hhs.gov/daltcp/reports/children.htm (accessed November 14, 2005). Elixhauser A., Steiner C., Harris R., Coffey R.M. 1998. "Comorbidity Measures for Use with Administrative Data," Medical Care 36:8-27. Hwang, W., Heller, W., Ireys, H., Anderson, G. 2001. "Out-Of-Pocket Medical Spending for Care of Chronic Conditions," Health Affairs 20, no. 6:267-278. Perrin EC, Newacheck P, Pless IB, Drotar D, Gortmaker SL, Leventhal J, Perrin JM, Stein RE, Walker DK, Weitzman M. 1993. "Issues Involved in the Definition and Classification of Chronic Health Conditions," Pediatrics 91, no. 4:787-793. Ozminkowski RJ, Smith MW, Coffey RM, Mark TL, Neslusan CA, Drabek J. (2000). "Private Payers Serving Individuals with Disabilities and Chronic Conditions" Report prepared under contract #HHS-100-95-0044, U.S. Department of Health and Human Services, Office of Disability, Aging and Long-Term Care Policy. http://aspe.hhs.gov/daltcp/reports/privpay.htm (accessed November 14, 2005). University of Manitoba. 2000. Chronic Disease Hospitalizations. An on-line concept dictionary to assist health services researchers with some groups of chronic conditions, http://www.umanitoba.ca/ centres/mchp/concept/dict/chronic_disease.htm. (accessed November 14, 2005). Wisconsin Department of Health and Family Services provides ICD-9-CM codes for chronic conditions http://www.dhfs.state.wi.us/localdata/chronicconditions/ CHRONICD.HTM (accessed October 18, 2004, no longer active). | ||||||||||||
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Questions regarding the Chronic Condition Indicator may be directed to HCUP User Support through the following channels:
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Internet Citation: HCUP Chronic Condition Indicator. Healthcare Cost and Utilization Project (HCUP). May 2016. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/toolssoftware/chronic/chronic.jsp. |
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