Supplemental Analyses for ICD-10-GM Crosswalks

This document provides further statistical analysis related to the cross-version evaluations of ICD-10.

Table of Contents

1. Genral

2. Non-automatic transition

   • Forward
   • Backward

3. Comparison of ICD-10 codes with version 2024

1. General

The German Federal Institute for Drugs and Medical Devices (BfArM) publishes so-called crosswalk tables. The crosswalk tables, in the form of text files, contain information on how a code in two subsequent versions behaves, for example:

K20 ; K20.0 ; X ; A

K20 ; K20.1 ; X ; X

T66 ; K20.1 ; X ; X

The first two columns show codes from the older version (blue) and the newer version (green). The remaining columns display transition information: from older to newer version (forward, orange) and from newer to older version (backward, red). An automatic transition is expressed by A in the tables. Non-automatic transition is represented by an empty entry in the tables, which, in this work, will be represented by X to improve readability. In total, 21 ICD-10-GM versions are considered between the years 2004 and 2024. Based on the provided Neo4J database and ConceptMaps R4 and R5 the analysis were carried out.

2. Non-automatic transition

Here it was analyzed how many codes cannot be automatically transitioned between two successive versions. In addition, five reasons were identified for the non-automatic transitions. These as well as examples and frequencies are also shown.

2.1. Forward

On average across the ICD-10-GM versions of 2004 and 2024, 0.89 % or 122 codes per crosswalk table cannot be transited automatically.

The following five causes for a non-automatic transition were identified:

Cause	Example	Frequency
■ Refinement/Coarsening	K20 → K20.1	30.30 %
■ New Codes	UNDEF → U69.75	20.48 %
■ Deleted Codes	U11.0 → UNDEF	1.85 %
■ Reorganization	T86.88 → T86.84	41.56 %
■ Reorganization with chapter change	T66 → K20.1	3.82 %

The causes and their frequencies per crosswalk table are as follows:

Two further examples of reorganization special (with chapter change):

Version	Code old	Name old	Code new	Name new
2022-2023	K20	Esophagitis	K20.1	Radiogenic esophagitis
			T66	Radiation sickness, unspecified
2016-2017	R60.9	Oedema, unspecified	E88.20	Lipoedema, stage I
			E88.21	Lipoedema, stage II
			E88.22	Lipoedema, stage III
			E88.28	Other and unspecified lipoedema

2.2. Backward

On average across the ICD-10-GM versions of 2004 and 2024, 0.48 % or 66 codes per crosswalk table cannot be transited automatically.

The following five causes for a non-automatic transition were identified:

Cause	Example	Frequency
■ Refinement/Coarsening	K20.1 → K20	3.96 %
■ New Codes	UNDEF → U11.0	3.13 %
■ Deleted Codes	U69.75 → UNDEF	37.80 %
■ Reorganization	T86.84 → T86.88	49.09 %
■ Reorganization with chapter change	K20.1 → T66	6.02 %

The causes and their frequencies per crosswalk table are as follows:

Two further examples of reorganization special (with chapter change):

Version	Code new	Name new	Code old	Name old
2023-2022	K20.1	Radiogenic esophagitis	K20	Esophagitis
			T66	Radiogenic esophagitis
2019-2018	G90.70	Complex regional pain syndrome of upper limb, other and unspecified type	M79.60	Pain in limb Multiple sites
			M79.61	Pain in limb Shoulder region
			M79.62	Pain in limb Upper arm
			M79.63	Pain in limb Forearm
			M79.64	Pain in limb Hand

3. Comparison of ICD-10 codes with version 2024

In the following section, the ICD-10 codes of the previous versions will be compared with those of the version 2024. This involves checking whether the codes of individual annual versions are still terminating in the version of 2024 or whether they still exist. In summary, the analysis yielded the following average results for the versions considered from 2004 to 2023:

• Still terminating in version 2024: 98.48 % (13,279 codes)
• No longer terminating in version 2024: 0.89 % (119 codes)
• No longer existing codes in version 2024: 0.63 % (84 codes).

The results for the individual annual versions are as follows:

Two examples of codes of version 2023 that can no longer terminating in version 2024:

Code (2023)	Name (2023)	Code (2024)	Name (2024)	Explanation
B18.8	Other chronic viral hepatitis	B18.80	Chronic viral hepatitis E	The code in the 2024 version has been refined by adding a 5th digit.
		B18.88	Other chronic viral hepatitis
S02.4	Fracture of malar and maxillary bones	S02.40	Fracture of malar, maxillary and zygoma bones, unspecified	The code in the 2024 version has been refined by adding a 5th digit.
		S02.42	Fracture of alveolus of maxilla
		S02.43	Unspecified severe protein-energy malnutrition
		S02.48	Malignant neoplasm: peritoneum, unspecified
		S02.49	Fracture of the zygomatic bone and maxilla: multiple parts