Part B Insider (Multispecialty) Coding Alert

Published on Sun Aug 22, 2004 PDF

 401.9 doesn't always cut it - and improved documentation is the key to more specific codes

Coding for hypertension should never feel like a coin toss. Here's how to get it right every time.

You need to know whether a patient's hypertension is malignant or benign in order to select the most definitive ICD-9 code. Unfortunately, physicians often don't provide adequate documentation on hypertension - and that can make assigning a specific code impossible.

Experts agree that improving physician documentation is the only way to improve your coding specificity. Follow these three easy steps to ensure your hypertension coding makes the grade:

1. Improve documentation

"The real key to correct coding for hypertension lies with physician documentation, and we need to educate our physicians to tell us explicitly" what type of hypertension they're treating, says Charla Prillaman, CPC, CHCO, director of physician compliance for Carolinas Healthcare System in Charlotte, NC. Physicians need to state the details of a patient's hypertension in the medical record, she adds.

Coding for hypertension "really comes down to documentation," agrees Jaime Darling, CPC, a coder with Graybill Medical Group in Escondido, Calif. Often physicians will simply write "hypertension" in the diagnosis portion of their notes, which leads a coder to nothing but 401.9 (Essential hypertension; unspecified), she says. Explain to your physicians that adequate information for medical purposes isn't always adequate for coding purposes.

Action: Ask your physicians to indicate whether a patient's hypertension is malignant or benign, and also to define how any other manifestations are related to the hypertension, Darling recommends. For example, the physician should not just document hypertension and renal disease, but should indicate if the patient's hypertension is causing renal disease or if the renal disease is causing hypertension.

2. Determine malignant or benign

The hypertension table in the ICD-9-CM manual's Index lists three possible categories into which hypertension may fall: 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.

Malignant hypertension is "a form of hypertension that progresses rapidly, accompanied by severe vascular damage," according to Taber's Cyclopedic Medical Dictionary, 19th Edition. Malignant hypertension can be life threatening and may cause a stroke, but is much less common than benign hypertension. 
 
Common assumption: Because benign hypertension is more common than malignant, physicians often assume they are indicating benign hypertension when they simply write "hypertension," Prillaman says. But if the documentation doesn't specifically state "benign" or "malignant," the only accurate choice you have is to report an unspecified code, she adds. 
 
Bright idea: If your physicians aren't keen on always having to write "benign" or "malignant," you might try this: Institute a set policy within your practice stating that, unless the physician specifies otherwise in the chart, he is indicating benign hypertension whenever he simply writes "hypertension," Darling suggests. Such a policy will allow you to rightfully move beyond "unspecified" to report a more specific code.

3. Identify primary or secondary

When documenting, physicians have to learn to link the patient's hypertension to any other manifestations, Darling says. And coders have to learn to discern the manifestations properly to assign the correct code.

Primary hypertension

If the patient's hypertension is primary, meaning that another condition is not causing the hypertension, then you need to list the hypertension code first. Then list any manifestations as secondary diagnoses, Darling says. However, patients sometimes have hypertension with another condition, such as renal disease, and there is one code that includes both conditions, she adds. For instance, the 403 code series indicates hypertensive renal disease, and the 404 series indicates hypertensive heart and renal disease.

Example #1: If your physician documents a patient with benign hypertensive renal disease with renal failure, you would report 403.11. You need only this one code to describe the patient's entire condition.

Example #2: If your physician treats a patient with benign hypertensive heart disease with heart failure, you would report 402.11. This code indicates the patient's entire hypertensive status, but you would also need to report an additional code to specify the type of heart failure, such as 428.0 (Congestive heart failure, unspecified).
 
Note: If the physician documents the patient has heart disease due to hypertension, he should also indicate whether the disease is with or without heart failure, Darling says. "This [distinction] will help the coder select the best code in the 402 or 404 categories," she adds. And if the patient does have heart failure, remember to assign a separate code to indicate the type of heart failure.

Secondary hypertension

A patient has secondary hypertension if the hypertension is "due to" or caused by another condition. ICD-9-CM 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 report the causal condition as the primary diagnosis and the hypertension as secondary. For example, if a patient has primary aldosteronism that is causing benign hypertension, you might report 255.10 (Primary aldosteronism) as the primary diagnosis and 405.19 (Secondary hypertension; benign; other) as the secondary.