An examination of ambulatory care code specificity utilization in ICD-10-CM compared to ICD-9-CM: implications for...

Area of Science:

• Health Informatics
• Medical Coding Systems
• Healthcare Data Analysis

Background:

• The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) was implemented to enhance data specificity compared to its predecessor, ICD-9-CM.
• A key objective was to improve the availability of detailed clinical data for healthcare analysis and reporting.

Purpose of the Study:

• To assess the utilization of increased specificity within the ICD-10-CM system in the ambulatory care setting.
• To inform evidence-based evaluation of ICD-11 content for future implementation in the United States.

Main Methods:

• Analysis of diagnosis codes and descriptions from a 25% random sample of the IQVIA Ambulatory EMR-US database for 2014 (ICD-9-CM) and 2019 (ICD-10-CM).
• Evaluation of code utilization rates, including total and unique codes used, and the proportion of unspecified codes for both systems.

Main Results:

• Only 44.6% of available ICD-10-CM codes were utilized, compared to 91.5% of ICD-9-CM codes.
• The percentage of unspecified codes increased from 14.5% (ICD-9-CM) to 33.3% (ICD-10-CM).

Conclusions:

• A significant increase in the use of unspecified codes (108.5%) was observed with ICD-10-CM, despite its greater detail.
• Current utilization patterns do not fully support the rationale for the substantial increase in ICD-10-CM code volume.
• Advanced technologies and methodologies may be necessary to effectively leverage the detailed information within sophisticated classification systems like ICD-10-CM and for future ICD-11 evaluation.