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. A Comorbid Diagnosis is coded by setting the Dx_Type to "comorbid".
When to code a Comorbid Diagnosis
- Dx is chronic and was present and known prior to admission, even if it was only discovered during this admission
- Dx is in the past and is resolved and is included in one of the: Category: Past medical history codes
- Dx is chronic and was not known prior to admission
- In this situation, code it as a Comorbid Diagnosis if it is a chronic, non-infectious condition -- e.g. a cancer, collagen-vascular disease (such as Systemic lupus erythematosis (SLE, lupus)), COPD, diabetes
- But do NOT code it as Comorbid Diagnosis if it is a chronic infectious condition -- such as Tuberculosis or AIDS (disease due to HIV) (which if first discovered/identified during the current admission would qualify as an Admit Diagnosis).
- Note that this rule does not impact on coding as a Comorbid Diagnosis an infection which is still present but WAS known pre-admission --- e.g. an osteomyelitis being treated at home with iv antibiotics.
When to use Comorbid Diagnosis vs Admit Diagnosis or neither
When not to code a dx at all
- Dx was present in the past but that problem is resolved AND does not fit into one of the Category: Past medical history codes
- To be clear on this -- do NOT code past problems that are fully resolved unless they are one of the Category: Past medical history codes
- Do not code diagnoses that occur during this admission as a comorbid diagnoses. If they have completely resolved then do not code as a comorbid diagnosis until the next admission if applicable. ie. surgical ward had a COVID pneumonia resolved prior to ICU admission. Do not code Past history of Covid-19 infection until the next hospital admission.
Regular comorbid rules exception: Strokes (of any sort, ischemic or hemorrhagic) -- code even resolved strokes with no current sequelae as comorbid diagnoses. If a patient has a past history of stroke, use the regular stroke codes to identify this, even if the patient does not have any residual deficits we will now capture ANY past history of stroke. This is contrary to the usual rules about Comorbid_Diagnosis#When_not_to_code_a_dx_at_all.
Some diagnoses can/should be coded as BOTH Admit Diagnosis and Comorbid Diagnosis
- Do not code a recurrent condition that is NOT currently present -- if currently active, include as Admit Diagnosis, otherwise don't code it
- Do code conditions that by nature have intermittent rather than continuous symptoms, but where the underlying condition doesn't go away.
Past medical history
Past medical history codes
Past medical history codes should only be captured as Comorbid Diagnoses that represent previous procedures or medical situations. Their names usually follow the pattern "Past history of X" or "X, has one". See Category:Past medical history for a list.
This wiki page talks about which ICD10 codes are allowed to be Comorbid Diagnosis vs. Admit Diagnosis vs. Acquired Diagnosis Dx Type. See Controlling Dx Type for ICD10 codes for a discussion about cross-checks for these.
Legacy - did not use to code Comorbid Diagnoses only discovered during this admission
|see how this used to be coded...|
signs and symptoms should not be code as comorbidities
- Signs, symptoms and findings (e.g. chest pain or dyspnea, or abnormal LFTs) should NOT be coded as comorbidities. Only real specific diagnoses should.
Patient has no comorbidities
If a patient has no comorbidities, enter No Comorbidities (ICD10 code).
You will need to enter priorities for comorbids. For comorbids the priorities will only be used for grouping Combined ICD10 codes, not for prioritizing them in any order of importance.
Transfer of Comorbids on transfer between wards
See Patient copier button for more.
Data Integrity Checks (automatic list)
|Controlling Dx Type for ICD10 codes||CCMDB.accdb||declined|
|Query check ICD10 duplicates||CCMDB.accdb||declined|
|Query check ICD10 date||CCMDB.accdb||implemented|
|Query check ICD10 Comorbids NoComo code but others||CCMDB.accdb||implemented|