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ICD-10-CM codes captured and not captured in charlson.sql #2017
Description
ICD-10-CM have three categories which are not part of the WHO ICD-10 and as such are not defined in Quan et.al (2005)
- C4A: Merkel cell carcinoma
- C7A: Malignant neuroendocrine tumors
- C7B: Secondary neuroendocrine tumors
One of the lines in the SQL for mapping ICD-10 to malignant cancer has a possible positive unexpected side effect
This will map C4A codes to malignant cancer. That seems conceptually okay but it opens the door for what to do with C7A and C7B codes.
If C4A is included in malignant cancer then shouldn't C7A codes?
Should C4A be excluded to be consistent with Quan et.al (2005)?
I think Merkel cells are part of the skin and since Quan et.al (2005) defines "any malignancy, including lymphoma and leukemia, except malignant neoplasm of skin" that C4A should be excluded?
Cancer is not my area of expertise, I honest have no idea. This is more of question of being consistent with the publication.
Activity
chessing234 commentedon Jul 19, 2026
c4a gets swept up by the
c45–c58string range; c7a/c7b sit in the gap betweenc76andc81. quan excludes skin malignancy, so excluding c4a (merkel) would match that. c7a probably belongs in malignant_cancer; c7b is secondary so maybe metastatic. say which convention you want and i can pr it.dewittpe commentedon Jul 20, 2026
I would exclude C4A, C7A, and C7B. All of these are ICD-10-CM specific. Quan (2005) was based on ICD-10 and the WHO standard.
fix: exclude ICD-10-CM C4A from Charlson malignancy
chessing234 commentedon Jul 23, 2026
excluded C4A from the C45–C58 malignancy range in #2124; C7A/C7B were already outside the WHO ranges.
docs(mimic-iv): add Charlson comorbidity concept README