Coding of Hypertension Warrants Second Look

Vol. 12 •Issue 13 • Page 8
CCS Prep!

Coding of Hypertension Warrants Second Look

By now, many have taken the June 15 CCS/CCS-P exams. The next and final CCS/CCS-P exams for 2002 will be held on September 14. The application deadline is July 12, 2002, with a final late entry deadline of August 2, 2002. Now on to the hypertension discussion!

There are different types, causes and co-morbid conditions associated with hypertension contained in ICD-9-CM. By far, the most commonly coded is essential hypertension, which codes to the 401 category, Hypertension, essential. Physicians typically do not document the type of hypertension as benign or malignant, which is needed to code to these types. Symptoms associated with essential hypertension include pulsating headaches, fatigue, confusion, visual disturbances or nausea and/or vomiting. Some of the medical treatments currently used for treating hypertension include diuretics, beta-adrenergic blocking agents, ACE inhibitors and angiotensin II blockers, calcium channel blockers, drugs with central sympatholytic action, alpha-receptor antagonists, arteriolar dilators or peripheral sympathetic inhibitors. Many patients are treated with a combination of these drugs. Unspecified or hypertension, NOS is coded to 401.9. The coder should never assume that hypertension is malignant or benign without physician documentation.

“Benign” must be stated by the physician along with hypertension to code 401.1.

Malignant or accelerated hypertension may result from sustained hypertension and may lead to encephalopathy, nephropathy, retinopathy, heart failure or myocardial ischemia. This may lead to a hypertensive emergency, papilledema and progressive renal failure. In ICD-9-CM, malignant or accelerated hypertension should only be assigned to the fourth-digit subcategory of “.0” in categories 401-404. Review Official Coding Guideline (OCG) 4.1 for instruction in coding essential hypertension. Coders must be cautious as to not code “uncontrolled” hypertension to the malignant hypertension code. Uncontrolled hypertension does not have a separate code in ICD-9-CM and is in fact, a non-essential modifier to the index entry of “Hypertension.”

In classifying hypertensive cardiovascular disease in ICD-9-CM, the physician must state that a relationship exists between the hypertension and the cardiac condition. This is never assumed and is based on the physician’s documentation within the medical record. Cardiac conditions that are combined with hypertension in category 402 include:

  • Hypertensive cardiomegaly
  • Hypertensive cardiopathy
  • Hypertensive cardiovascular disease
  • Hypertensive heart disease or failure
  • Any condition classifiable to 425.8, 428, 429.0-429.3, 429.8, 429.9 due to hypertension

    Should any other cardiac condition be documented within the same record with hypertension, hypertension should be assigned to the appropriate code from category 401, Essential hypertension, and a separate code should be assigned for the cardiac condition. Do not assume the connection unless stated by the physician.

    The subclassification codes in category 402, Hypertensive heart disease, identify whether congestive heart failure (CHF) is also present. CHF should be assigned when it is also under treatment during an admission for a patient with hypertensive heart disease. Code 402.X0 is used for hypertensive cardiovascular disease without CHF, code 402.X1 is used for hypertensive cardiovascular disease with CHF. See OCG 4.2 for discussion of hypertensive cardiovascular disease.

    Hypertensive cerebrovascular disease is a leading cause of stroke, including that due to intracerebral hemorrhage or cerebral infarction. The incidence of hypertensive cerebrovascular disease is decreased by successful treatment of the hypertension.

    Based on the OCG 4.5, hypertensive cerebrovascular disease is assigned two separate ICD-9-CM codes. There are no combination codes to identify these diseases. First, the appropriate code from categories 430-438, Cerebrovascular disease, should be assigned, followed by the appropriate code from categories 401-405, Hypertension.

    Hypertensive renal disease is due to the presence of chronic hypertension leading to nephrosclerosis and renal damage. It is also an exacerbating or accelerating factor in the progression of other renal diseases, such as diabetic nephropathy.

    ICD-9-CM assumes a relationship between hypertension and renal disease that does not need to be stated by the physician. This is, however, not true in the case of acute renal failure. Acute renal failure should be coded separately with the appropriate code from category 584. Hypertensive renal disease (category 403) does include chronic renal failure, which can be identified with fifth-digit subclassification codes. Assign the code 403.X1 if the patient has chronic renal failure documented by the physician. Assign fifth digit “0” if there is no documentation of chronic renal failure.

    Hypertensive renal disease includes the following conditions: arteriolar nephritis; arteriosclerosis of kidney; arteriosclerosis of renal arterioles; chronic arteriosclerotic nephritis; interstitial arteriosclerotic nephritis; hypertensive nephropathy; hypertensive renal failure; chronic hypertensive uremia; nephrosclerosis; renal sclerosis with hypertension; any condition classifiable to 585, 586, or 587 with any condition classifiable to 401.

    When a patient is documented to have both hypertensive heart disease and hypertensive renal disease, OCG 4.4 applies. In other words, the relationship between hypertension and heart disease must be stated, while the relationship between hypertension and renal disease is assumed. The subclassification codes identify whether the patient has CHF and/or chronic renal failure in addition to hypertensive heart and renal disease. See fifth digits 0-3 in the tabular listing.

    A hypertensive crisis or uncontrolled hypertension, unspecified as to whether it is malignant or benign, should be assigned to code 401.9, Unspecified essential hypertension, based on the non-essential modifier of “(crisis)” in the alphabetic index. See OCG 4.10. Many coders incorrectly assume that hypertensive crisis is accelerated hypertension.

    Secondary hypertension accounts for about 5 percent of all patients suffering from hypertension. Causes may be varied and include estrogen use, renal disease, renal vascular hypertension, primary hyperaldosteronism and Cushing’s syndrome, pheochromocytoma, coarctation of the aorta, hypertension during pregnancy, as well as others.

    According to OCG 4.7, secondary hypertension requires the assignment of two codes, one identifying the etiology of the hypertension and one from category 405, Secondary hypertension. Sequencing is dependent upon the circumstances of the admission.

    Transient hypertension or elevated blood pressure should be assigned to code 796.2, Elevated blood pressure without diagnosis of hypertension. The coder should never assume that elevated blood pressure implies hypertension.

    Finally, one important point to remember in assigning codes from categories 401-405: when a code is assigned from categories 402-405, it is inappropriate to also assign a code from category 401 on the same medical record.

    For additional information on the coding of hypertension, refer to the following Coding Clinics:

  • Fourth Quarter, 1997, p. 37
  • Issue #5, 1993, pp. 6-7
  • Fourth Quarter, 1993, p. 37
  • Second Quarter, 1993, p. 9
  • First Quarter, 1993, pp. 17-20
  • Fourth Quarter, 1992, pp. 22-23
  • Second Quarter, 1992, p. 5
  • First Quarter, 1991, p. 16
  • Third Quarter, 1990, pp. 3-4
  • Second Quarter, 1989, p. 12
  • Third Quarter, 1988, pp. 3-5
  • September/October, 1987, pp. 9, 11
  • November/December, 1985, p. 15
  • May/June, 1985, p. 19
  • November/December, 1984, p. 18
  • September/October, 1984, p. 4
  • July/August, 1984, pp. 12-17

    Additionally, refer to the Offi-cial Coding Guidelines, section 4, Hypertension, and in AHA’s ICD-9-CM Coding Handbook, with Answers, 2002 Revised Edition, by Faye Brown.

    Now test your hypertension coding and medications knowledge with the quiz below:

    1. Which medication is commonly used to treat hypertension?

    a) Lanoxin

    b) Accupril

    c) Zocor

    2. In the ICD-9-CM alphabetical index, Hypertension is listed in table format.

    a) True

    b) False

    3..Transient hypertension oc-curring during the postoperative period is coded as:

    a) 401.9

    b) 997.91, 401.9

    c) 997.91, 796.2

    d) 796.2

    4. A patient has a final diagnosis of malignant hypertension and heart disease. This is coded as:

    a) 401.0

    b) 401.0, 429.9

    c) 402.90

    5. How is CHF due to diastolic dysfunction due to hypertension coded?

    a) 402.91

    b) 429.9, 428.0, 401.9

    c) 402.91, 429.9

    6. Which medication is used to treat mild to moderate hypertension or hypertensive crisis and is also a treatment for congestive heart failure?

    a) Persantine

    b) Furosemide

    c) Norpace

    7. Nephrosclerosis is coded as:

    a) 586

    b) 403.91

    c) 403.90

    8. Hypertensive cardiovascular disease with acute renal failure and CHF is coded:

    a) 404.93

    b) 402.91, 584.9

    c) 401.9, 428.0, 584.9

    Now check your answers to see how you did.

    1. b) Accupril ;

    2. a) True;

    3. d) 796.2 (Transient hypertension) The MD has not documented that the transient hypertension is postoperative so the complication code cannot be used. Transient hypertension is considered elevated blood pressure;

    4. b) 401.0, 429.9 (Code separately as a causal relationship has not been documented by the MD. OCG 4.5);

    5. a) 402.91 (Hypertensive cardiovascular disease with CHF);

    6. b) Furosemide (otherwise known as Lasix);

    7. c) 403.90 (There is no mention of renal failure);

    8. b) 402.91, 584.9

    Should you have any questions, send an e-mail to ADVANCE at [email protected].

    Patricia Maccariella-Hafey is director of education for Health Information Associates Inc., a company specializing in providing coding compliance review services, coding education and contract coding for health care facilities. The corporate office is headquartered in Pawley’s Island, SC.

    Coding Clinic is published quarterly by the American Hospital Association.

    “CPT only© 2001 American Medical Association. All Rights Reserved.”