Conversion of the Agency for Healthcare Research and Quality's Quality Indicators from ICD-9-CM to ICD-10-CM/PCS: The Process, Results, and Implications for Users

Abstract

Objective: To convert the Agency for Healthcare Research and Quality's (AHRQ) Quality Indicators (QIs) from International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) specifications to ICD, 10th Revision, Clinical Modification and Procedure Classification System (ICD-10-CM/PCS) specifications.

Data sources: ICD-9-CM and ICD-10-CM/PCS classifications, General Equivalence Maps (GEMs).

Study design: We convened 77 clinicians and coders to evaluate ICD-10-CM/PCS codes mapped from ICD-9-CM using automated GEMs. We reviewed codes to develop "legacy" specifications resembling those in ICD-9-CM and "enhanced" specifications addressing enhanced capabilities of ICD-10-CM/PCS.

Data collection/extraction methods: We tabulated the numbers of mapped codes, added nonmapped codes, and deleted mapped codes to achieve the specifications.

Principal findings: Of 212 clinical concepts (sets of codes) that comprise the QI specifications, we either added nonmapped codes to or deleted mapped codes from 115 (54 percent). The legacy and enhanced specifications differed for 46 sets (22 percent), affecting 67 of the 101 QIs (66 percent). Occasionally, concepts that defied conversion required reformulation of indicators.

Conclusions: Converting the AHRQ QIs to ICD-10-CM/PCS required a detailed, thorough process beyond automated mapping of codes. Differences between the legacy and enhanced versions of the QIs are frequently minor but sometimes substantive.

Keywords: GEMs; ICD-10-CM/PCS; ICD-9-CM; Quality indicators; administrative data.

Figure 1

Association between the Number of ICD‐9‐CM Codes in Version 4.5 of the QI Specifications and the Number of ICD‐10‐CM/PCS Codes Resulting from Automated Use of GEMs, Depicted Separately for Each Clinical Concept (“Set of Codes”) Embedded in the QI Specifications (N = 212 Sets)Note. Data points are offset by a small random distance (“jittered”) to facilitate presentation.

Figure 2

Changes in the Numbers of ICD‐9‐CM or ICD‐10‐CM Diagnosis Codes for Each Clinical Concept (“Set of Codes”) in the QI Specifications as a Result of Converting Mapped Codes to the “Enhanced” QI Specifications Note. Arrows indicate the changes for each set. (Only 75 sets with a change in the number of codes in ICD‐9‐CM or ICD‐10‐CM are depicted in this figure. Due to the logarithmic scale, three sets that we could not convert to a single code in ICD‐10‐CM are depicted only as a mapped set.)

Figure 3

Changes in the Numbers of ICD‐9‐CM or ICD‐10‐PCS Procedure Codes for Each Clinical Concept (“Set of Codes”) in the QI Specifications as a Result of Converting Mapped Codes to the “Enhanced” QI Specifications Note. Arrows indicate the changes for each set. (Only 38 sets with a change in the number of codes in ICD‐9‐CM or ICD‐10‐PCS are depicted in this figure. Due to the logarithmic scale, two sets that we could not convert to a single code in ICD‐10‐PCS are depicted only as a mapped set.)