Podiatry Coding & Billing Alert

Question: My podiatrist is treating a patient who has diabetes and peripheral angiopathy and has developed a stage 4 decubitus ulcer on their right heel, which is also gangrenous. I understand that coding for this condition can be complicated, but could you advise on the sequence in which I should list the codes? Since the diabetes is a major contributing factor, does that come first, since it was the likely cause of the other problems?

AAPC Forum Participant

Answer: The first thing you’ll want to do is clarify what type of diabetes the patient suffers from. There are four types of specified diabetes groups and an unspecified category, each having their own code sets: E08 (Diabetes mellitus due to underlying condition), E09 (Drug or chemical induced diabetes mellitus), E10 (Type 1 diabetes mellitus), E11 (Type 2 diabetes mellitus), and E13 (Other specified diabetes mellitus).

If the provider doesn’t clarify which form of diabetes the patient has in the notes, or you are unable to verify which type even after querying the provider, do not use a code from E13. Instead, follow ICD-10-CM guideline, 1.C.4.a.2, which tells you to use a code from E11 as the default code. (For the purposes of this answer, E11 will also be our default code.)

Sequencing will be another important factor when coding this patient. Should you code diabetes, the pressure ulcer, or the gangrene first? ICD-10-CM guideline IV.G tells you to “list first the ICD-10-CM code for the diagnosis, condition, problem, or other reason for encounter/visit shown in the medical record to be chiefly responsible for the services provided” for all outpatient services. For coding this decubitus ulcer, you should use L89.614 (Pressure ulcer of right heel, stage 4) to identify the location, but you should also list E11.622 (Type 2 diabetes mellitus with other skin ulcer) first because L89.614 only identifies the location, not the connection between diabetes and the ulcer. Based on guideline I.C.4.a for diabetes, you should connect diabetes to all conditions listed under “with” in the index.

Next, you’ll need to determine the order of the remaining conditions: diabetes, peripheral angiopathy, or gangrene. Luckily, there’s a single code that encompasses all these conditions — E11.52 (Type 2 diabetes mellitus with diabetic peripheral angiopathy with gangrene). This code would be the appropriate choice, rather than coding each condition individually.

Although gangrene is the primary diagnosis, it’s a complication that’s likely influenced by both diabetes and peripheral angiopathy. Peripheral angiopathy restricts blood circulation and healing in the area, which heightens the risk of gangrene and exacerbates the decubitus ulcer. Meanwhile, diabetes enhances the probability of gangrene and infection. Therefore, all the conditions contributing to the primary diagnosis should be accounted for.

By including each of these known factors, we can create a complete picture of what is happening with the patient and why. By listing all the conditions responsible for the patient’s visit will help explain the medical necessity for the provider’s plan of care for the patient, which will facilitate payer reimbursement.