Primary Care Coding Alert

Many family practices report that diagnosis coding for hypertension can be problematic because chart notes often dont provide adequate specificity. When assigning codes, professional coders are required to distinguish between malignant, benign and unspecified hypertension. If the proper distinction is not made, third-party payers may reject the accompanying procedure codes describing physical exams or diagnostic tests because certain services are approved only with malignant (401.0) or benign (401.1) essential hypertension, but not for unspecified (401.9) essential hypertension.

The fundamental problem arises when a physician merely notes hypertension on the chart, leaving coders unsure of a precise diagnosis. Even reviewing the patient chart more closely may not provide coders with adequate information because there is confusion about which clinical terms apply to which types of hypertension, says Paula Casto, CPC, billing supervisor for a physician practice in Irving, Texas. When coders are unsure, they often assign the unspecified code, which may not be appropriate.

To solve this problem, coders must understand these diagnostic codes and educate practice physicians about the importance of using the ICD-9 definitions when diagnosing hypertension.

Malignant vs. Benign vs. Unspecified Hypertension

The diagnosis codes most often assigned for hypertension (401.x) are classified as essential hypertension, which means the cause for the condition is unknown. Many additional hypertensive conditions in the ICD-9 manual are not considered essential because they are a secondary symptom of another disease (i.e., 403.x, hypertensive renal disease) and the physician can pinpoint what caused the hypertension.

Malignant hypertension is clinically defined as accelerated hypertension with papilledema (edema of the optic disk) and indicates an urgent situation, according to Colleen King, RN, practice administrator for Worthington Industrial Medical Center in Columbus, Ohio. The patients blood pressure has risen rapidly to very high levels, 230 or 240 over 130, for instance, she says. It demands immediate attention because it indicates a critical condition. If malignant hypertension is not controlled, patients may experience organ damage in the retina, kidneys and brain. Untreated, the illness two-year survival rate is lower than 50 percent.

On the other hand, benign essential hypertension is characterized by a more moderate elevation in blood pressure that may happen gradually. In addition, no symptoms of contributing diseases are present. This form of hypertension comprises 90 to 95 percent of all cases, and is the type most frequently treated by family physicians.

Many healthcare professionals regard unspecified as a coding term, rather than a medical term, and indicate it is used only when there is not enough clinical information to categorize the disease as malignant or benign. Coders should avoid using the unspecified code when chart notes dont identify benign or malignant, but should instead confer with the physician to report the more precise diagnosis.

Some family practice coders also confuse the clinical terms malignant and benign with controlled and uncontrolled hypertension, which might also appear in chart notes. King points out that controlled/uncontrolled terminology simply describes the efficacy of the treatment, and should not be used to determine a diagnosis code.

Note: The ICD-9 2001 manual contains a comprehensive chart outlining the proper codes for various conditions in the Index to Diseases within the Hypertension/hypertensive entry.

Frequency Edits Demand Correct ICD-9 Coding

Assigning the accurate hypertension diagnosis code is particularly important when working with payers who employ frequency edits in their claims-processing software. When a patients benign hypertension is success-fully managed, for instance, some payers may allow only three 99214 services (office or other outpatient visit, established patient) within a three-month period. Like-wise, even if the condition is uncontrolled, some payers may limit the number of office visits for benign or unspecified hypertension, but may be more lenient if the condition has been diagnosed as malignant.

Of course, frequency edits may cause claim denials even if the diagnosis is reported correctly. If practices believe claims are being inappropriately rejected, they should question the payers policies.

Use Alternative Codes During Pregnancy

ICD-9 provides an alternative set of codes to describe hypertension that develops as a result of pregnancy. The 642 series (hypertension complicating pregnancy, childbirth, and the puerperium) is assigned instead. These codes were developed because this type of hypertension is a temporary condition that disappears when the pregnancy ends. However, it can be a precursor to other serious complications (e.g., eclampsia, 642.6x) and so is watched carefully.

Each code in the 642 series requires a fourth digit and one of the following fifth digits, indicating the condition and denoting the current episode of care:

0 unspecified as to episode of care or not applicable;
1 delivered, with or without mention of antepartum condition;
2 delivered, with mention of postpartum complication;
3 antepartum condition or complication; or
4 postpartum condition or complication.