The Chronic Condition Indicator for the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) 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 (AHRQ). HCUP databases, tools, and software inform decision making at the national, State, and community levels.

Contents:

• Overview of the Chronic Condition Indicator for ICD-10-CM Tool
• Description of the Chronic Condition Indicator for the ICD-10-CM Tool
• Technical Guidance of the Chronic Condition Indicator for the ICD-10-CM Tool
• Downloading Information for the Chronic Condition Indicator for the ICD-10-CM Tool
• Publications Using the Chronic Condition Indicator for the ICD-10-CM Tool
• For More Information, Comments, or Questions About the Chronic Condition Indicator for the ICD-10-CM Tool
• References

The Chronic Condition Indicator is created to facilitate health services research on diagnoses using administrative data. This classification system allows researchers to readily determine whether 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.

The Chronic Condition Indicator provides an easy way for users to categorize ICD-10-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. Not chronic conditions include conditions such as infections, pregnancy, many neonatal conditions, nonspecific symptoms, and injuries. To obtain the entire listing of all conditions, view the downloadable file that contains a listing of all ICD-10-CM codes and their assignment to chronic or not chronic.

Diagnosis codes for this tool are based on the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM), a uniform and standardized coding system. The ICD-10-CM has a multitude of codes—over 69,800 diagnosis codes.

This documentation provides an overview of the following:

• The categorization scheme used by the Chronic Condition Indicator
• A description of downloadable, electronic files that contain the translation of ICD-10-CM diagnosis codes into the Chronic Condition Indicator

The Chronic Condition Indicator is updated each year. The current version is based on 2017 ICD-10-CM diagnosis codes. ICD-10-CM is currently valid as of October 1, 2015.

The Chronic Condition Indicator categorizes all ICD-10-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:

(1) it places limitations on self-care, independent living, and social interactions; and

(2) it results in the need for ongoing intervention with medical products, services, and special equipment.¹

The identification of chronic conditions is based on all 7-digit ICD-10-CM codes. External cause of injury codes are not classified because all injuries are assumed to be not chronic.

Background

The algorithm originated with work reported by Hwang et al.² in which selected 3-digit ICD-9-CM codes were classified as chronic conditions. That study used 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 the Hwang et al. study, a physician panel reviewed each diagnosis code that appeared in MEPS data and determined whether the code represented a chronic condition.

The Hwang et al. 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. 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 the Hwang et al. classification as well as other sources that provided information on the chronicity of specific conditions.^3,4,5,6,7

Disagreements with the original classification of Hwang et al. were resolved in consultation with one of the original physician panel members. As a final step, an expert medical coder reviewed the assignment of all ICD-9-CM codes, resulting in the reassignment of some codes.

Logic Employed for ICD-10-CM Chronic Condition Indicator Mapping

In preparation for the October 2015 implementation of ICD-10-CM, the diagnosis and procedure tools from HCUP were converted to the new coding system.

The mapping was completed by linking ICD-10-CM diagnosis codes to the current Chronic Condition Indicator assignments via the General Equivalence Mappings (GEMs) available from the Centers for Medicare & Medicaid Services (CMS) Web site (see http://www.cms.gov/Medicare/Coding/ICD10/2014-ICD-10-CM-and-GEMs.html for more information on GEMS). Two GEMs are available for the CM code set; ICD9 to ICD10 and ICD10 to ICD9. In order to ensure complete inclusion of both ICD-9-CM and ICD-10-CM codes, both code maps were combined and de-duplicated to form a complete many-to-many map that included all ICD-9-CM and ICD-10-CM codes. This approach was used to ensure that all applicable codes would be used in the mapping process that centered on the Chronic Condition Indicator assignments.

Continuing to use the Hwang et al. designation of chronic (1) versus not chronic (0) with other references mentioned above, ICD-10-CM codes assignments were made. In addition there were a number of exceptions to the Hwang et al. designation of chronic (1) versus not chronic (0) for ICD-9-CM. These exceptions were used and updated for ICD-10-CM and are as follows:

1. When a 4-, 5-, 6-, or 7-character code within a 3-character series whose ICD-9-CM equivalent reviewed by Hwang et al. is explicitly chronic, the code is designated as chronic (e.g., see chronic viral hepatitis codes B18.0-B18.2).



2. When an ICD-9-CM code was not reviewed by Hwang, one of the other sources was used to decide whether it is chronic or not chronic.



3. When an ICD-9-CM code was not reviewed by Hwang et al. but is similar to other codes that were reviewed, we followed the Hwang et al. designation (e.g., see the tuberculosis codes).



4. A potentially disabling code3 is not considered a determining factor, unless it is clear that it will result in a chronic condition.



5. When an ICD code is listed as "not otherwise specified" or "not elsewhere classified," it is not designated as a chronic condition, unless it is clearly and explicitly a chronic condition (e.g., E07.89 other specified disorders of the thyroid and E07.9 disorder of the thyroid, unspecified).



6. When a code is listed as "history of...," it is not designated as a chronic condition because it is assumed that the condition is no longer active.



7. All congenital anomalies are designated as chronic conditions.



8. All cancers are considered chronic with the following exceptions:
   
   
   • Most basal cell carcinomas (C44.00-C44.99); however, basal cell carcinomas of the female genital and male genital are considered chronic.
   
   
   
   • All benign neoplasms are considered nonchronic except benign neoplasms of the brain, cranial nerves, and cerebral meninges (D32.0, D32.9, D33.0-D33.3).
   
   
   
   • Carcinomas in situ are considered chronic except for skin (D04.-) and cervix (D06.-).
   
   
   
   • Neoplasms of uncertain behavior are considered nonchronic except neurofibromatosis and neoplasms of uncertain behavior of the brain.

Because of the change in the code structure for some diseases (i.e., combination codes) and the few one-to-one matches between the code sets, it was necessary to add rules to the above list.

1. ICD-10-CM diabetes codes are combination codes that include the type of diabetes, the complication, and any associated manifestation into a single code. Where it took two or more codes to complete the coding process in ICD-9-CM, it only takes one code in ICD-10-CM. All diabetes codes (E08.- through E13.-) are considered chronic conditions.



2. The alcohol and drug use, abuse, and dependency codes have been expanded in ICD-10-CM. Some use, abuse, and dependency codes are combination codes that include the addiction code and an associated manifestation condition (i.e., hallucinations) in a single code. All "use" codes are indicated as not chronic. All "abuse" codes are indicated as chronic. All "dependency" codes are indicated as chronic.



3. Several ICD-9-CM "open wound codes" changed to partial or complete traumatic amputation codes in ICD-10-CM. The mapping structure considers all traumatic amputations chronic. Therefore, ICD-10-CM amputation codes, such as, S08.811x Complete traumatic amputation of the nose, are classified as chronic conditions.



4. The mapping between ICD-9-CM and ICD-10-CM is often not a one-to-one match. There can be one-to-many matches and many-to-one matches between the code sets. In the instances in which one ICD-10-CM code mapped to many ICD-9-CM codes, the following guidelines were used.
   
   
   • If all of the ICD-9-CM codes were not chronic, then the ICD-10-CM code was indicated as not chronic.
   
   
   
   • If all of the ICD-9-CM codes were chronic, then the ICD-10-CM code was indicated as chronic.
   
   
   
   • If some of the ICD-9-CM codes were not chronic and some were chronic, then the ICD-10-CM code was indicated as chronic unless the description of the ICD-10-CM code was clearly and explicitly an acute or transient condition (e.g., F23, Brief psychotic disorder).

Body System Indicator

In an effort to keep data consist across the ICD-9-CM to ICD-10-CM conversion, the body system indicator is based on the chapters of the ICD-9-CM codebook. This indicator may be useful as a means of counting the number of body systems affected by chronic conditions. Alternatively, the Clinical Classifications Software (CCS) may be used in conjunction with the Chronic Condition Indicator to obtain a count of the number of relatively discrete chronic conditions.

System Requirements

In order to use the Chronic Condition Indicator file for ICD-10-CM, you will need a program (such as WinZip®) that will allow you to decompress or "unzip" files. You will also need approximately five megabytes of disk space available on your hard drive to accommodate the Chronic Condition Indicator file.

Required Data Elements

The Chronic Condition Indicator file for ICD-10-CM requires diagnosis codes (ICD-10-CM) with no embedded periods.

File Layout

The Chronic Condition Indicator file for ICD-10-CM is composed of four fields separated by commas. The file is organized as follows:

• Field 1: Diagnosis Code
• Field 2: Code Description
• Field 3: Chronic Condition Indicator
• Field 4: Body System Indicator

"Unzipping" the File

There is one downloadable self-extracting zipped file called cci_icd10cm_2017.zip. Users are advised to:

1. Create a subdirectory (or folder) called CCI on your hard drive (e.g., C:\CCI)
2. Download and save cci_icd10cm_2017.zip to this subdirectory
3. Using WinZip (or comparable program), double click on the zip file to expand the file

The zipped file will unzip (expand for normal use) the following file: cci_icd10cm_2017.csv. Note that the original file (cci_icd10cm_2017.csv.zip) will remain intact.

Using the Translation File

The translation file translates specific ICD-10-CM codes into Chronic Condition Indicator and Body System categories. Your use of the file will depend on the software system being used. For example, if you are using SAS, you can adapt these translations to create a SAS PROC FORMAT. If you are working with SPSS, you can adapt these translations into VALUE LABELS or into a series of recodes.

The chronic indicator is defined as either 0-not 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

Representation of ICD-10-CM Diagnosis Codes

In practice, ICD-10-CM diagnoses are represented by 3- to 7-character codes with explicit decimals. In the files that you downloaded and in the vast majority of data files, ICD-10-CM diagnoses are represented with implicit decimals (no decimals present). (Alphanumeric codes are always enclosed in quotation marks.) Examples are given below.

For proper handling of diagnosis codes, perform the following steps:

• Alphanumeric diagnosis codes must be left-justified so that there are two spaces following a 5-character diagnosis code and one space following a 6-character diagnosis code. For example, 'J206 '.



• Trailing blanks should never be zero-padded (filled with zeroes so that all 7 characters are filled for codes that should be 3 or 4 characters long). For example, 'A191' should not be changed to 'A191000'.

Calculating the number of chronic conditions (NCHRONIC): Users who wish to determine the number of chronic conditions on a discharge record will need to do the following:

1. The first step is to assign chronic condition indicators to a dataset using the tool. This entails creating an array of chronic condition indicators on each record that is equal in size to the number of diagnoses on the record. If each record has 15 diagnosis fields (DX1-DX15), then 15 chronic condition indicators should be created (CHRON1-CHRON15). Each chronic condition indicator would be created using the corresponding diagnosis array element (CHRON5 would be created by examining the fifth diagnosis-DX5). Users should also assign the CCS diagnosis categories to their data if they are not already present (link to CCS). This is required for the next step.



2. Once an array of chronic conditions data elements is made for each record, users should loop through said array to find any instances of a chronic condition (CHRONn=1). To avoid double counting of chronic conditions for the same basic condition (as defined using CCS categories), users should check the CCS array element that corresponds to a chronic condition against previous CCS array elements to ensure that the CCS value is not repeated. If the same CCS category is not repeated, then the count of chronic conditions should be incremented by one. For example, if the CHRON6 shows a chronic condition, the corresponding CCS (CCS6) should be checked against the previous CCS array elements (CCS1-CCS5) to determine whether the corresponding chronic condition has already been counted.

Note: New diagnoses codes were added for Fiscal Year 2017.

Shift-click from this Web page: Your browser may support loading the file for the ICD-10-CM Chronic Condition Indicator from this Web page. To download the file from this Web page, click on the following link with the right mouse button and select Save Link As (Firefox) or Save Target As (Internet Explorer). After saving the file, find the file by using Windows® Explorer (Windows 98/95/NT/Vista/7/8/10) or File Manager (Windows 3.x), and then open it by double clicking on it.

ASCII Chronic Condition Indicator for ICD-10-CM file for Use with user analytic software (i.e., SAS, STATA, or SPSS) cci_icd10cm_2017.zip (ZIP file, 494 KB).

There are currently no publications using Chronic Condition Indicator for ICD-10-CM Tool. Selected publications that use the ICD-9-CM version of the CCI include:

Fox J P, Philip E J, Gross C P, Desai RA, Killelea B, Desai MM. 2013. "Associations between mental health and surgical outcomes among women undergoing mastectomy for cancer." Breast Journal.

Hansen M, Fleischman R, Meckler G, Newgard CD. 2013. "The association between hospital type and mortality among critically ill children in US EDs." Resuscitation.

Miller CM, Shi J, Wheeler KK, Yin H, Smith GA, Groner J I, Xiang H. 2013. "Chronic conditions and outcomes of pediatric trauma patients." Journal of Trauma Acute Care Surgery.

Sammon J, Trinh VQ, Ravi P, Sukumar S, Gervais M K, Shariat SF, Larouche A, Tian Z, Kim SP, Kowalczyk KJ, Hu JC, Menon M, Karakiewicz PI, Trinh QD, Sun M. 2013. "Health care-associated infections after major cancer surgery: Temporal trends, patterns of care, and effect on mortality." Cancer.

Sharp AL, Choi H, Hayward RA. 2013. "Don't get sick on the weekend: an evaluation of the weekend effect on mortality for patients visiting US EDs." American Journal of Emergency Medicine.

Steiner CA, Friedman B. 2013. "Hospital utilization, costs, and mortality for adults with multiple chronic conditions, nationwide inpatient sample, 2009." Prev Chronic Dis.

Sun GH, Auger KA, Aliu O, Patrick SW, DeMonner S, Davis MM. 2013. "Variation in inpatient tonsillectomy costs within and between US hospitals attributable to postoperative complications." Med Care.

Ahuja N, Zhao W, Xiang H. 2013. "Medical errors in US pediatric inpatients with chronic conditions." Pediatrics.

Friedman B, Jiang HJ, Steiner CA, Bott J. 2012. "Likelihood of hospital readmission after first discharge: Medicare Advantage vs. fee-for-service patients." Inquiry.

Chi MJ, Lee CY, Wu SC. 2011. "The prevalence of chronic conditions and medical expenditures of the elderly by chronic condition indicator (CCI)." Archives of gerontology and geriatrics.

Friedman B, Jiang HJ. 2010. "Do Medicare Advantage enrollees tend to be admitted to hospitals with better or worse outcomes compared with fee-for-service enrollees?" Int J Health Care Finance Econ.

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.

Questions regarding the Chronic Condition Indicator may be directed to HCUP User Support through the following channels:

• email: hcup@ahrq.gov
• Phone (toll free): 1-866-290-HCUP

1. Perrin EC, Newacheck P, Pless IB, et al. Issues involved in the definition and classification of chronic health conditions. Pediatrics. 1993;91:787-93.
2. Hwang W, Weller W, Irey, H, et al. Out-of-pocket medical spending for care of chronic conditions. Health Aff. 2001;20(6):267-8.
3. Burwell B, Crown W, Drabek J. Children With Severe Chronic Conditions on Medicaid Washington, DC: U.S. Department of Health and Human Services; November 1997. Report available at http://aspe.hhs.gov/daltcp/reports/children.htm. Accessed September 8, 2014.
4. Elixhauser A, Steiner C, Harris R, Coffey RM. Comorbidity measures for use with administrative data. Med Care. 1998;36:8-27.
5. Ozminkowski RJ, Smith MW, Coffey RM, et al. Private Payers Serving Individuals With Disabilities and Chronic Conditions." Washington, DC: U.S. Department of Health and Human Services; January 2000. Report available at http://aspe.hhs.gov/daltcp/reports/2000/privpay.htm. Accessed September 8, 2014.
6. University of Manitoba. Concept Dictionary and Glossary for Health Services Research; updated August 16, 2012. http://umanitoba.ca/faculties/medicine/units/community_health_sciences/departmental_units/mchp/resources/concept_dictionary.html. Accessed September 8, 2014.