Clinical Classifications Software for ICD-10 Data:
Since 1999, mortality data in the United States have been coded using the International Statistical Classification of Disease and Related Health Problems, 10th Revision. Clinical Classifications Software for ICD-10 provides a way to classify diagnoses into a limited number of categories. CCS aggregates individual ICD-10 codes into broad diagnosis groups to facilitate statistical analysis and reporting with mortality data.
This document describes the ICD-10 CCS categorization scheme. Select to Download Files containing the translation of ICD-10 diagnosis codes into CCS categories.
Developed at the Agency for Healthcare Research and Quality (AHRQ), Clinical Classifications Software (CCS) is continually updated. The current version is based on ICD-10 codes that are valid through September 2003. CCS was formerly called CCHPR, Clinical Classifications for Health Policy Research.
CCS categories can be employed in many types of projects analyzing data on diagnoses. For example, they can be used to:
- Identify cases for disease-specific studies.
- Gain a better understanding of the distribution of certain conditions across disease groupings.
- Examine trends in mortality by broad diagnosis groupings.
The diagnosis section of the CCS has now been translated into ICD-10 to facilitate its use.
CCHPR Version 1 was the initial endeavor to construct clinically meaningful categories of diagnoses and procedures. The determining factor in creating these categories was the extent to which conditions and procedures could be grouped into relatively homogeneous clusters of interest to public policy researchers. CCHPR Version 1 consisted of 185 summary diagnosis categories and 172 summary procedure categories (Elixhauser, Andrews, and Fox, 1993).
CCHPR Version 2 was derived from the Version 1 summary diagnosis and procedure categories. Version 1 categories were modified on the basis of clinical homogeneity, frequency of occurrence in inpatient discharge data, and ICD-9-CM coding changes. The number of discharges in all categories was computed using 1991 California hospital inpatient data on all listed diagnoses and all listed procedures from the Healthcare Cost and Utilization Project (HCUP) and State Inpatient Databases (SID).
The modified CCHPR schemes went through reviews during which the categories and ICD-9-CM code assignments were evaluated for accuracy and clinical significance. The reviews were conducted by trained medical records personnel and a physician with experience in medical classification. During this review process, additional categories were created, other categories were collapsed, and codes were reassigned when appropriate.
Version 2 contained more categories than Version 1. Some conglomerate categories (e.g., "Other gastrointestinal procedures") and high frequency categories (e.g., "Pregnancy related conditions") were divided into smaller, more clinically homogeneous groups.
With the 1999 update, an additional classification scheme was introduced, E codes (external causes of injury) receive special treatment, and the name was changed to Clinical Classification Software (CCS), reflecting the broader use of the classifications beyond health policy research. The single-level CCS is identical to CCHPR Version 2, updated for FY1999 ICD-9-CM coding changes. However, while E codes were previously aggregated into a single category, now users are given the option of classifying E codes into categories based on a scheme developed by the Centers for Disease Control and Prevention. The multi-level CCS is a hierarchical system that groups single-level CCS categories into broader categories and splits single-level CCS into finer categories to provide more detail.
Beginning in 1999, ICD-10 has been used to code causes of death in U.S. mortality data. The single-level diagnosis section of the CCS has been translated into ICD-10 to facilitate its use with these data.
Description of ICD-10 CCS
The single-level diagnosis ICD-10 CCS aggregates illnesses and conditions into 259 mutually exclusive categories, most of which are clinically homogeneous. Some heterogeneous categories were necessary; these combine several less common individual conditions within a body system. The category names for the single-level diagnosis ICD-10 CCS are presented in Appendix A (select to download file).
Period Covered by ICD-10 CCS
The 2001 version of the CCS is valid through September 2003. The codes will be updated annually, as ICD-10 codes are modified.
Using Translation Files
For the ICD-10 CCS, the translation files translate specific ICD-10 codes into CCS categories. How you use these files 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 using SPSS, you can adapt these translations into VALUE LABELS or into a series of recodes.
Representation of ICD-10 Diagnosis Codes
In practice, ICD-10 diagnoses are represented by 3- to 5-character codes with explicit decimals. Each code begins with an alphabetic character that generally corresponds to the ICD-10 chapter:
|A-B||Infectious and parasitic diseases|
|D00-D09||In situ neoplasms|
|D50-D89||Diseases of blood, blood-forming organs, immune mechanism|
|E||Endocrine, nutritional, and metabolic disease|
|F||Mental and behavioral disorders|
|G||Diseases of the nervous system|
|H00-H59||Diseases of the eye and adnexa|
|H60-H95||Diseases of the ear and mastoid process|
|I||Diseases of the circulatory system|
|J||Diseases of the respiratory system|
|K||Diseases of the digestive system|
|L||Diseases of skin and subcutaneous tissue|
|M||Diseases of the musculoskeletal system and connective tissue|
|N||Diseases of the genitourinary system|
|O||Pregnancy, childbirth, and the puerperium|
|P||Certain conditions originating in the perinatal period|
|Q||Congenital malformations, deformations, and chromosomal abnormalities|
|R||Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified|
|S-T||Injury, poisoning, and certain other consequences of external causes|
|V-Y||External causes of morbidity and mortality|
|Z||Factors influencing health status and contact with health services|
In the files you downloaded and in the vast majority of data files, ICD-10 codes are represented as 5 character alphanumeric codes with implicit decimals (i.e., the decimal point may not be present in your data). Alphanumeric codes are always enclosed in quotation marks. Examples are given below.
|Bacterial pneumonia||J15||'J15 '|
|Pneumonia due to Klebsiella pneumoniae||J15.0||'J150 '|
For proper handling of diagnosis codes:
- Alphanumeric diagnosis codes must be left justified so that there are 2 spaces following a 3-character diagnosis code and 1 space following a 4-character diagnosis code.
- Trailing blanks should never be zero padded (filled with zeroes so that all 5 characters are filled for codes that should be 3 or 4 characters long).
Agency for Health Care Policy and Research. Statistics from the HCUP 3 Nationwide Inpatient Sample for 1992: Principal diagnoses. Healthcare Cost and Utilization Project (HCUP 3) Pocket Guide. Rockville, MD: Agency for Health Care Policy and Research; 1996. AHCPR Publication No. 96-0029.
Centers for Disease Control and Prevention. Recommended framework for presenting injury mortality data. Morbidity and Mortality Weekly Report 1997 Aug 29;46(no. RR14):1-30.
Cowen ME, Dusseau DJ, Toth BG, et al. Casemix adjustment of managed care claims data using the clinical classifications for health policy research method. Medical Care 1998, 36:1108-1113.
DRGs: Diagnosis related groups definitions manual, version 12.0. Wallingford, CT: 3M Health Information Systems; 1994.
Duffy SQ, Elixhauser A, Sommers JP. Diagnosis and procedure combinations in hospital inpatient data. Healthcare Cost and Utilization Project (HCUP 3) Research Note 5. Rockville, MD: Agency for Health Care Policy and Research; 1996. AHCPR Publication No. 96-0047.
Elixhauser A, Andrews RM, Fox, S. Clinical classifications for health policy research: Discharge statistics by principal diagnosis and procedure. Provider Studies Research Note 17. Rockville, MD: Agency for Health Care Policy and Research; 1993. AHCPR Publication No. 93-0043.
Elixhauser A, McCarthy EM. Clinical classifications for health policy research, version 2: Hospital inpatient statistics. Healthcare Cost and Utilization Project (HCUP 3) Research Note 1. Rockville, MD: Agency for Health Care Policy and Research; 1996. AHCPR Publication No. 96-0017.
Elixhauser A, Steiner CA, Whittington C, et al. Clinical classifications for health policy research: Hospital inpatient statistics, 1995. Healthcare Cost and Utilization Project, HCUP 3 Research Note. Rockville, MD: Agency for Health Care Policy and Research; 1998. AHCPR Publication No. 98-0049.
Elixhauser A, Steiner CA. Hospital inpatient statistics, 1996. Healthcare Cost and Utilization Project (HCUP) Research Note. Rockville, MD: Agency for Health Care Policy and Research; in press, 1999. AHCPR Publication No. 99-0034.
Public Health Service and Health Care Financing Administration. International classification of diseases, 9th revision, clinical modification. Vols. 1, 2, and 3; fifth edition. Washington, DC: Public Health Service; 1994. DHHS Publication No. (PHS) 94 1260.
Your browser may support downloading the files from this Web page. To download the executable files, right click on the links and then select "Save Target As" (Internet Explorer) or "Save Link As" (Netscape):
- ICD-10 CCS.TXT (1.2 MB) translates ICD-10 codes into single-level CCS diagnosis categories.
- Appendixes (Zipped File, 550 KB). Appendix A contains the full descriptive single-level CCS diagnosis category names to use when reporting the diagnosis categories.
- CCS software and for the User's Guide.