Home Health ICD-9/ICD-10 Alert

Tip: Physician documentation determines how specific your hypertension coding can be.

The Centers for Medicare & Medicaid Services may have decided to keep awarding case mix points for certain hypertension diagnoses, but that doesn't mean your claims are in the clear. Make certain you don't wind up on the wrong side of a hypertension edit by boning up on these coding basics.

When you don't know whether your patient's hypertension is malignant or benign, you can't assume the physician means benign, says Trish Twombly, RN, BSN, HCS-D,CHCE, director of coding with Foundation Management Services in Denton, Texas. Only a physician can indicate whether hypertension is malignant or benign.

Bottom line: If the physician doesn't specify whether your patient's hypertension is benign or malignant, you must code for it with 401.9 (Essential hypertension, unspecified). "Do not use either .0 malignant or .1 benign unless medical record documentation supports such a designation," advises the 2011 ICD-9-CM Official Guidelines for Coding and Reporting.

When you look up "hypertension" in your ICD- 9 manual's alphabetic index, you'll notice that the hypertension table lists three possible categories: malignant, benign, and unspecified. The fourth digit of the hypertension code you report will differ depending on which category you choose. For instance, you'll report 401.0 for malignant essential hypertension, 401.1 for benign essential hypertension, and 401.9 for unspecified.

Physicians often assume they are indicating benign hypertension when they simply write "hypertension" because benign hypertension is more common. But if the documentation doesn't specifically state "benign" or "malignant," the only accurate choice you can report is 401.9. If you suspect that a physician is making this assumption, you may want to educate him on this point.

Another hypertension assumption you must avoid is listing 401.0 for a patient who had malignant hypertension during a recent hospital stay. The patient may have had malignant hypertension while in the hospital, but it may no longer be malignant once he returns home.

"Malignant hypertension is rare to code in home health," says Lisa Selman-Holman, JD, BSN, RN, HCSD, COS-C, consultant and principal of Selman-Holman & Associates and CoDR -- Coding Done Right in Denton, Texas. Patients with malignant hypertension have a sustained diastolic blood pressure of 120 or greater despite treatment, she says. Malignant hypertension is more common in black Americans and can be a home care diagnosis. In this type of patient, the condition is not usually resolved by the time they return home, she says.

Your work doesn't end once you've identified whether the hypertension is benign or malignant these categories only refer to idiopathic hypertension -- the kind of hypertension that occurs without apparent organic cause, Twombly says.

You'll also need to show whether the hypertension is primary or secondary to your patient's condition. Most hypertension is considered primary or essential hypertension, and coded with a 401.x category code. Primary hypertension can also be categorized according to end organ involvement: hypertensive heart disease with or without heart failure (402.xx), hypertensive chronic kidney disease (403.x), or hypertensive heart and chronic kidney disease (404.x).

Secondary hypertension (405) will be documented by the physician as such and should not be coded otherwise.

Keep in mind: Patients sometimes have hypertension and chronic kidney disease, and ICD-9-CM assumes a causeand- effect relationship. In this case, 403.xx (Hypertensive chronic kidney disease) indicates hypertensive chronic kidney disease and includes any conditions coded to 401.x, 585.x (Chronic kidney disease [CKD]), and 587 (Renal sclerosis, unspecified)

Note: Ordinarily when a condition is included in a code you would not also include a code to report that condition individually. However, even though CKD is included in 403.xx (Hypertensive chronic kidney disease), your coding manual includes an instruction to use additional code from the 585.x series to indicate the stage of the chronic kidney disease.

Renal sclerosis (587) was added to the 403.x inclusion note Oct. 1, but there is no instruction to also list the code for renal sclerosis, Selman-Holman says. There are also no instructions in the tabular list nor in the guidelines that indicate which fifth digit you should choose for hypertension with renal sclerosis. This issue is "up in the air" until further guidance is issued, she adds.

Tip: With hypertensive chronic kidney disease, the hypertension is considered to have caused the CKD. Sequence the 585.x code to indicate the stage of the patient's CKD immediately following the 403.x code.

Code category 404.xx (Hypertensive heart and chronic kidney disease) indicates hypertensive heart and chronic kidney disease and cannot be coded unless there is documentation of hypertensive heart disease.

Red flag: Kidney conditions reported with codes other than 585 and 587 are not considered hypertensive chronic kidney disease and are not coded with a 403 category code.

If the physician documents that the patient has heart disease due to hypertension, he should also indicate whether the disease is with or without heart failure. This distinction will help you select the best code in the 402.x or 404.x categories. And if the patient has heart failure, remember to assign a separate code to indicate the type of heart failure.

A patient has secondary hypertension if the hypertension is "due to" or caused by another condition. ICD-9 defines secondary hypertension as "high arterial blood pressure due to or with a variety of primary diseases, such as renal disorders, CNS disorders, endocrine, and vascular diseases."

For secondary hypertension, you should sequence the causal condition first and the hypertension second. For example, if a patient has primary aldosteronism that is causing benign hypertension, you might report 255.10 (Primary aldosteronism) followed by 405.19 (Secondary hypertension; benign; other).