If anyone wondering why it is call 'downcoding', it's because there's WHO ICD coding standard or international classification of diseases now at version 11 or ICD-11 [1]. It's mainly used for classification of disease mortality not morbidity, not until the latest version iteration of ICD-11 in which it now caters for both [2].
Due the usefulness of the diseases classification coding based on ICD, it's also being used in many part of the world especially in US for healthcare insurance claim purposes.
[1] International Classification of Diseases 11th Revision:
The global standard for diagnostic health information:
No, that's completely wrong. Downcoding has nothing to do with ICD versions. This article is talking about changes to the billed HCPCS (including CPT) codes to ones with lower rates. Most US healthcare claims do include at least one ICD-10-CM code to indicate the diagnosis but this is just supporting information. Payers don't change diagnosis codes. ICD-11 isn't used on US claims at all, although it might be adopted in a few years.
Due the usefulness of the diseases classification coding based on ICD, it's also being used in many part of the world especially in US for healthcare insurance claim purposes.
[1] International Classification of Diseases 11th Revision: The global standard for diagnostic health information:
https://icd.who.int/en/
[2] ICD-11 vs. ICD-10 - a review of updates and novelties introduced in the latest version of the WHO International Classification of Diseases:
https://pubmed.ncbi.nlm.nih.gov/32447353/