POA Exempt use for all comorbidity methods

[dewittpe]

AHRQ Elixhauser ICD-10 methods consider present on admission (POA) exempt ICD codes. For example, ICD-10-CM I69.031 maps to PARALYSIS. It does not matter is the code I69.031 is POA = 1, POA = 0, or POA is NA, the condition PARALYSIS will be flagged. Additionally, there are conditions which are POA exempt.

Other comorbidity methods do not explicitly use the POA exempt list. This can lead to issues. For example, in my own experience with PCCC there has been a desire to have malignancy flagged regardless of the POA status of codes while other conditions should require POA. The manuscripts for PCCC v2 and v3 do not explicitly define any use of POA exemptions.

I propose an option for POA exemptions to be considered for all comorbidity methods. There will be a argument to comorbidities() allowing the end user to opt out of this option.

Things to do:

• Add poaexempt flags to the ICD code database
• Explore the relationships between the Elixhauser comorbidities and the other methods to identify the conditions in the other methods which should be POA exempt, or rather, in that parlance, require POA.
• Build test scripts
• Document and provided examples
  • roxygen
  • examples
  • vignettes