HCC Diagnosis Coding: Can you Add a Code from the Past Medical History?

This post describes rules for office/outpatient coding, not facility/DRG rules.

Recently a fellow coder wrote to me about risk adjusted diagnosis coding. She was responding to an article that I wrote in which I stated the conditions listed in the past medical history should not be included on the claim form by the coder. I stated that in order to include the condition on the claim form, there should be documentation in the history of the present illness or the assessment and the plan that the condition was assessed and managed  at the encounter.

She and I were in agreement that we should follow the ICD-10 guideline that states:

“Code all documented conditions that coexist at the time of the encounter and require or affect patient care or treatment.”

Here is her comment:

“However, I am a believer that although the patient is not being seen or treated for the chronic condition or history of condition, they all play a pertinent part in the patient care and overall acuity of the patient.

An example is patient had CVA listed in the PMH and current encounter is for thigh pain without known injury.   There could be a correlation to a thrombosis or blood clot that the physician must consider.   The physician does not document this correlation, however the old CVA could affect treatment or care.  Coding history of CVA code as a secondary would give a clear picture.”

While I applaud her clinical knowledge, when selecting ICD-10 codes for office visits, follow ICD-10-rules and CMS risk adjustment guides.

Problem lists, and past medical history in electronic health records

But, while it may be relevant to this encounter, without documentation that the clinician was thinking about this past stroke,  I would not add it to the claim form. I wouldn’t assume that the physician/NP/PA was thinking about that in terms of the thigh pain after the injury, even though it is on the problem list. In order for me to use the past history of the stroke on the claim form, I would have had to see that the clinician mentioned it in the history of present illness.

For example, the HPI might say,

“He does have a history of stroke, and with his recent injury is at risk of a clot.” 

Or, the assessment and plan might say,

“I have reassured him that his symptoms are not consistent with a blood clot, and there is no reason to order an ultrasound.” Or, “I think in light of his history of a stroke, we should do further testing to rule out a thrombolytic event.” 

And while I agree with her that the history provides a clearer picture, it is the physician’s job to document a picture.

CodingIntel has a more in-depth article about the ICD-10 and CMS risk adjustment rules in code selection.

Risk Coding for Medical Practices and Outpatient Services

Conditions that affect patient care

The example I use most frequently is the patient who presents to urgent care with a bad case of poison ivy.  If the urgent care provider says in the assessment, “I’d like to give her prednisone, but I’m not going to because of her diabetes,” then I add diabetes to the claim form.  The diabetes affected patient care and the clinician documented that it affected patient care.  If the diabetes is listed in the problem list but not mentioned in the encounter for this date of service, I do not add it to the claim form.

Risk adjustment for history of conditions

But would history of a stroke increase the risk score? That is, if the group has risk based contracts, does adding history of stroke increase the risk score for that patient? The answer is no. The diagnosis codes for current stroke and sequelae of a past stroke  (I63, I69) do have HCC weighted scores assigned to him. But past history of the stroke does not. This brings me to a compliance issue in HCC coding.

HCC compliance issues

Medical groups that are part of Accountable Care Organizations (ACOs) or that have commercial risk based contracts need to assign diagnosis codes carefully.

Additional resources

The CodingIntel Guide to Hierarchical Condition Categories provides a comprehensive list of HCC and Risk Adjusted Diagnosis Coding resources available on CodingIntel.