The Clinical Classifications Software (CCS) for ICD-10 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:

• Overview of CCS for ICD-10
• Description of CCS for ICD-10
• Time Period Covered by CCS for ICD-10
• Representation of ICD-10 Diagnosis Codes
• Using the Translation Files
• References
• For More Information About CCS for ICD-10
• Downloading Information for CCS for ICD-10 Software
• Questions?

The Clinical Classifications Software (CCS) for ICD-10 is a diagnosis categorization scheme that can be employed in many types of projects analyzing data on diagnoses. This tool is based on the International Classification of Diseases, 10th Revision (ICD-10), a uniform and standardized coding system, which has been used in the U.S. for mortality reporting since 1999. The ICD-10’s multitude of codes – more than 32,000 diagnosis codes in all – are collapsed into a smaller number of clinically meaningful categories that are sometimes more useful for presenting descriptive statistics than are individual ICD-10-CM codes.

CCS for ICD-10 categories can be employed in many types of projects analyzing data on diagnoses. For example, they can be used to:

• Identify populations 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.

For the history of CCS development, see the original CCS Software and User’s Guide.

The CCS for ICD-10 aggregates illnesses and conditions into 260 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 CCS for ICD-10 are in the label file dxlabel_2006.csv.

The Fiscal Year 2006 version of the CCS for ICD-10 is valid through September 2009. No ICD-10 coding changes were implemented by the World Health Organization in 2007, 2008, or 2009, thus no changes were necessary in this tool for those years.

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:

In the tool file available here 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.

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).

Certain WHO ICD-10 codes found in the CCS tool contain special ASCII symbols in the final position of the code. These symbols, "+" and "*", are used by clinical coders when making initial coding assignments. They should be removed from the tool prior to merging with user data in cases where said data do not contain these characters. One could use the Replace feature in Excel to remove them, or alternatively, one could employ SAS code similar to the following example in a SAS Data Step: icd10 code = compress (icd10code, "*+"); .

The CCS for ICD-10 consists of one translation table in Comma Separated Values (CSV) file format that creates CCS for ICD-10 categories for data sets that contain ICD-10 diagnosis information. How the translation file is used will depend on the software system being used. For example, if SAS is employed, the translation table could be adapted to create a SAS PROC FORMAT. If SPSS is used, the translation file could be adapted into VALUE LABELS or into a series of recodes. In Stata, the translation table could be modified through a series of GENERATE and REPLACE commands.

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 (CDC). 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.

Send Questions & Comments to: hcup@ahrq.gov.

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CCS for ICD-10 Documentation

• CCS Labels (ASCII text file, 11 KB).
  Note: The CCS Label file provides full labels for all CCS diagnosis categories.
• CCS Software and User's Guide (ICD-9-CM).

CCS Program File (Used to map ICD-10 codes into CCS categories)

• CCS for ICD-10 Program File (in ZIP format).

Current as of January 2009

Questions regarding the CCS for ICD-10 may be directed to HCUP User Support through the following channels:

• e-mail: hcup@ahrq.gov.

Phone (toll free): 1-866-290-HCUP.