Comorbid Diagnosis

For other diagnoses we collect see Admit Diagnosis or Acquired Diagnosis / Complication.

Comorbid Diagnoses are for diseases the patient has had for some time. Comorbidities can be a factor in increasing the patient risk of dying; see Charlson Comorbidity Index.

Collection Instructions

Code diagnoses that were obviously present prior to admission.

Code these even if the diagnosis of the condition was only made during the current hospital admission.

If a diagnosis is an acute event following long term comorbidity, code it as Admit Diagnosis instead.

• Example 1: if a patient is admitted with the DX of pneumonia and on further workup is found to have CA of the lung, then this is coded in comorbid as it is obvious that is process has been there for a while prior to admission.
• Example 2: patient comes in with abdominal pain. DX as gastroenteritis but incidentally pt is found to be HIV +ve. You would code HIV +ve as a comorbid. Again, this is obvious that the pt had this problem for a while prior to admission to the hospital. If you don't code it as a comorbid until the patients show up again the next time to the hospital you have missed information. It is better to over report than under report.
• Example 3:If a pt is having CABG surgery and in the same admission, prior to the surgery, had an acute MI, the MI should also be listed as part of the diagnosis after the CABG. If the pt had an MI in a previous admission, this would be a comorbid.

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ICD 10

Template:ICD10 This is how this will be done in ICD10. For example, we only used to allow a subset of all diagnosis codes as comorbids. We will now allow all, right? What will that mean for differences in data and reporting?

Coding for comorbid dxs will follow the general ICD10 collection instructions.