This web page summarizes key issues for researchers using HCUP and other administrative databases that include International Classification of Diseases, 10th Revision, Clinical Modification/Procedure Coding System (ICD-10-CM/PCS) coding. The page documents key differences in the structure of HCUP databases, provides general guidance to users analyzing outcomes that may be affected by the transition to the ICD-10-CM/PCS coding system, and lists other related resources.

In October 2015, the United States transitioned to the ICD-10-CM diagnosis coding system for most inpatient and outpatient medical encounters and the ICD-10-PCS procedure coding system for inpatient hospital procedures. This transition had a direct impact on the reporting of medical services and health services research.

Contents:

• General Information about ICD-10-CM/PCS
• HCUP Databases and ICD-10-CM/PCS-Related Data Elements: The Transition Year
• Doing Analysis with ICD-10-CM/PCS Data
• AHRQ-Sponsored Software Tools Using ICD-10-CM/PCS
• Other Federal or State Web Resources with Information on ICD-10-CM/PCS

• Brief Introduction to ICD-10-CM/PCS Codes (PDF file, 488 KB)
• Method Series Report #2016-02: Impact of ICD-10-CM/PCS on Research Using Administrative Databases (PDF file, 1.2 MB)

• 2015 HCUP State Databases—revised structure and new data elements (PDF file, 379 KB)
• 2015 HCUP Nationwide Databases—change in structure and data elements
  • 2015 HCUP National Inpatient Sample (NIS) (PDF file 304 KB)
  • 2015 HCUP Nationwide Readmissions Database (NRD) (PDF file,553 KB)
  • 2015 HCUP Nationwide Emergency Department Sample (NEDS) (PDF file, 560 KB)

• HCUP Recommendations for Reporting Trends Using ICD-9-CM and ICD-10-CM/PCS Data (PDF file, 165 KB)
• Number of Diagnosis and Procedures Codes (PDF file, 136 KB)
• ICD-10-CM/PCS Coding in HCUP Data: Comparisons with ICD-9-CM and Precautions for Trend Analyses
  • ICD-10-PCS Procedure Coding Trends (PDF file, 1.2 MB)
  • ICD-10-CM Diagnosis Coding Trends (PDF file, 1.6 MB)
• Opioid-Related Diagnosis Codes: Case Studies
  • Trends in Opioid-related Inpatient Stays Shifted After the US Transitioned to ICD-10-CM Diagnosis Coding in 2015 Med Care. 2017; 55(11):918-923. (PDF file, 295 KB)
  • Preliminary Case Study: Exploring How Opioid-Related Diagnosis Codes Translate from ICD-9-CM to ICD-10-CM (PDF file, 656 KB)
• Readmission Analyses
  • Impact of the ICD-10-CM/PCS Transition on Readmission Rates, 2015-2017 (PDF file, 359 KB)
    • Supplemental Tables (Excel file, 285 KB)
• Other Case Studies
  • Case Study: National Healthcare Quality and Disparities Report (QDR) Sensitivity Analysis on Developing AHRQ Quality Indicator Estimates for 2015 Using Only ICD-9-CM Data (PDF file, 286 KB)

• AHRQualityIndicators™: The AHRQ Quality Indicators (QI) are are standardized, evidence-based measures of healthcare quality that can be used with readily available hospital inpatient administrative data to measure and track clinical performance and outcomes.
• HCUP Tools for ICD-10-CM/PCS: The HCUP tools have been translated to the ICD-10-CM/PCS coding system.
  
  
  • The Clinical Classifications Software Refined (CCSR) for ICD-10-CM aggregates over 70,000 ICD-10-CM diagnosis codes into a manageable number of clinically meaningful categories. The categories are organized across 21 body systems, which generally follow the structure of the ICD-10-CM diagnosis chapters. This initial release of the CCSR replaces the beta version of the CCS for ICD-10-CM diagnoses and applies to all ICD-10-CM diagnosis codes valid through fiscal year 2019. It provides a means by which to identify specific clinical conditions using ICD-10-CM diagnosis codes. The CCSR for ICD-10-CM capitalizes on the specificity of the ICD-10-CM coding scheme by creating new clinical categories that did not exist in previous versions of the CCS tool and allowing ICD-10-CM codes to be classified in more than one category. The CCSR is intended to be used analytically to examine patterns of healthcare in terms of cost, utilization and outcomes, rank utilization by diagnoses, and risk adjust by clinical condition.
  • Clinical Classifications Software (CCS) for ICD-10-PCS (beta version) provides a method for classifying ICD-10-PCS procedures into clinically meaningful categories, which can be used for aggregate statistical reporting of a variety of types. (Updated for codes valid through FY 2019.) A fully refined version of the CCS for ICD-10-PCS is expected to be released in 2020.
  • Chronic Condition Indicator for ICD-10-CM (beta version) provides a method for categorizing ICD-10-CM diagnosis codes into one of two categories: chronic or not chronic. The tool can also assign ICD-10-CM diagnosis codes into 1 of 18 body system categories. (Updated for codes valid through FY 2019.) A fully refined version of the Chronic Condition Indicator for ICD-10-CM is expected to be released in 2019.
  • Elixhauser Comorbidity Software for ICD-10-CM (beta version) assigns variables that identify coexisting conditions on hospital discharge records. (Updated for codes valid through FY 2019.) A fully refined version of the Comorbidity Software for ICD-10-CM is expected to be released in 2019.
  • Procedure Classes for ICD-10-PCS (beta version) provides a method for identifying whether an ICD-10-PCS procedure is (a) diagnostic or therapeutic, and (b) minor or major in terms of invasiveness and/or resource use. (Updated for codes valid through FY 2019.) A fully refined version of the Procedure Classes for ICD-10-PCS is expected to be released in 2020.
  • Utilization Flags for ICD-10-PCS (beta version) combines information from UB-04 revenue codes and ICD-10-PCS procedure codes to create flags, or indicators, of utilization. Use of procedures and services such as ICU, CCU, NICU, and specific diagnostic tests and therapies can be assessed with these Utilization Flags. (Updated for codes valid through FY 2019.) A fully refined version of the Utilization Flags for ICD-10-PCS is expected to be released in 2021.


• ICD-10-CM/PCS Formats Program (txt file, 705 KB): A program to create SAS® formats that label the ICD-10-CM/PCS codes.

• The MapIT tool is an automated mapping tool developed by AHRQ and the Centers for Disease Control and Prevention (CDC) that uses General Equivalence Mappings (GEMs) to provide forward and backward (or reverse) mapping between ICD-9-CM and ICD-10-CM codes.
• The Centers for Medicare & Medicaid Services (CMS): The ICD-10-CM/PCS Resources on the CMS website include statute and regulations, frequently asked questions, and the GEMs mapping for diagnosis and procedure codes by fiscal year release of ICD-10-CM/PCS.
• National Association of Health Data Organizations (NAHDO) ICD-9/ICD-10 Transition Tools.
• ICD-10 Implementation: Opportunities and Challenges for Health Data Organizations by Patrick S. Romano, MD MPH (PDF file, 924 KB)
  • This presentation was given at the NAHDO Annual Meeting, 2016. The work presented in the slides was funded in part by the CDC and AHRQ.
• Challenges and Opportunities with ICD-10-CM/PCS: Implications for Surgical Research Involving Administrative Data. J Am Coll Surg. 2013; 217(3):516-526. (PDF file 353 KB)
• The CDC National Center for Health Statistics (NCHS) Classification of Diseases, Functioning, and Disability ICD-10-CM home page

AHRQ welcomes suggestions for additional Federal and State ICD-10-CM/PCS Web Resources. Please e-mail us at hcup@ahrq.gov.