Properly coding hypertension diagnoses is essential for accurate medical billing. This guide explains CD-10 codes for hypertension in a comprehensive and easy-to-understand way.

Understanding ICD-10 Codes for Hypertension: A Comprehensive Guide

ICD-10 codes for hypertension

Table of Contents

A person is considered to have hypertension if they have a systolic blood pressure (SBP) that is at least 140 mmHg or a diastolic blood pressure (DBP) that is at least 90 mmHg. Both primary and secondary forms of hypertension exist. Essential hypertension is the more common form.
Hypertension can be classified by severity as mild (SBP of 140-159 mmHg or DBP of 90-99 mmHg), moderate (SBP of 160-179 mmHg or DBP of 100-109 mmHg), or severe (SBP of 180 mmHg or higher or DBP of 110 mmHg or higher).

ICD-10 codes for hypertension

Codes Code Description
I10 Essential (primary) hypertension, benign
I11 Hypertensive heart disease
I12 Hypertensive chronic kidney disease
I13 Hypertensive heart disease and chronic kidney disease
I15 Secondary hypertension
I15.0 Renovascular hypertension
I15.1 Hypertension secondary to other renal diseases
I15.2 Hypertension secondary to endocrine disorders
I15.3 Hypertension secondary to drugs
I15.4 Hypertension secondary to other diseases
I15.8 Other secondary hypertension
I15.9 Secondary hypertension, unspecified
I16 Hypertensive crisis
I16.0 Hypertensive emergency
I16.1 Hypertensive urgency
I16.9 Hypertensive crisis, unspecified

When coding for hypertension, it is important to note the following:

Hypertension Headaches

High blood pressure, or hypertension, occurs when the force of blood against the artery walls is consistently higher than normal. This can induce blood vessel and organ injury over time. When hypertension affects the brain’s blood vessels, migraines may result. The migraines could be caused by an increase in blood vessel pressure or by a constriction of the blood vessels, which reduces blood supply to the brain. Headaches caused by hypertension are typically described as pulsating pain on both sides of the head, which may be accompanied by vertigo or nausea.

The ICD-10 code for hypertension headache is G44.2.

Hypertensive heart disease

Hypertensive heart disease is a condition that occurs when high blood pressure damages the heart. This damage can lead to a number of problems, including:

ICD-10-CM presumes a causal relationship between hypertension and heart involvement and classifies hypertension and heart conditions to category I11 (hypertensive heart disease) because the two conditions are linked by the term “with” in the Alphabetic Index of ICD-10-CM. These conditions should be coded as related even in the absence of provider documentation linking them. Code first I11.0 (hypertensive heart disease with heart failure) as instructed by the note at category I50 (heart failure). If the provider specifically documents different causes for the hypertension and the heart condition, the heart condition (I50.-, I51.4 to I51.9) and hypertension are coded separately.

Hypertension and Heart Failure

Category I11 is subdivided to indicate whether heart failure is present. However, an additional code from category I50 is required to specify the type of heart failure, if known.
Documentation may vary, but coding instructions remain the same. For example:

Hypertension and CKD

When the diagnostic statement includes both hypertension and CKD, ICD-10-CM assumes there is a cause-and-effect relationship. A code from category I12 (hypertensive CKD) is assigned because the two conditions are linked by the term “with” in the Alphabetic Index of ICD-10-CM. These conditions should be coded as related even in the absence of provider documentation linking them, unless the documentation clearly states the conditions are unrelated.1

A fourth character is used with category I12 to indicate the stage of the CKD. The appropriate code from category N18 should be used as a secondary code to identify the stage of CKD.

Hypertensive cerebrovascular disease

For hypertensive cerebrovascular disease, first the appropriate code from categories I60 to I69 is assigned followed by the hypertension code.
Hypertensive retinopathySubcategory H35.0 (background retinopathy and retinal vascular changes) should be used with a code from category I10 to I15 (hypertensive disease to include the systemic hypertension).
Hypertension, secondary

Two codes are required — one to identify the underlying etiology and one from category I15 to identify the hypertension. For example:

  • Hypertension due to systemic lupus erythematosus: M32.10 + I15.8
  • Acromegaly with secondary hypertension seen for hypertension management: I15.2 + E22.0

Hypertension, transient

Code R03.0 (elevated blood pressure reading without diagnosis of hypertension) is assigned unless the patient has an established diagnosis of hypertension. For transient hypertension of pregnancy, code O13.- (gestational [pregnancy-induced] hypertension without significant proteinuria) or O14.- (pre-eclampsia).

Hypertensive crisis

A code from category I16 (hypertensive crisis) is assigned for any documented hypertensive urgency, hypertensive emergency or unspecified hypertensive crisis. Report two codes, at a minimum, for hypertensive crisis. The crisis code is reported in addition to the underlying hypertension code (I10 to I15).

  • Hypertensive urgency: I16.0
  • Hypertensive emergency: I16.1
  • Hypertensive crisis, unspecified: I16.9

More coding tips

Blood pressure and medication management should be assessed at every encounter involving a hypertensive patient. Clarity is important in documenting hypertension. Ensure that the diagnosis is captured by noting it in the medical record documentation:

  • Specify a pregnant patient with hypertension as having a pre-existing, gestational, pre-eclampsic or eclampsic hypertension.
  • Document and code the smoking status of a patient with hypertension:
    • For current smokers: use category 17 codes
    • Personal history of tobacco dependence: Z87.891
    • Tobacco use: Z72.0
    • Exposure to environmental tobacco smoke: Z57.31
  • Document any causal relationship between hypertension and background retinopathy or other conditions in which the hypertension caused vascular changes and organ damage.

Strategies for success

  • Improve the accuracy of BP measurements performed by your clinical staff by:
    • Providing training materials from the American Heart Association.
    • Conducting BP competency tests to validate the education of each clinical staff member.
    • Making a variety of cuff sizes available.
  • Instruct your office staff to recheck BPs for all patients with initial recorded readings greater than systolic 140 mm Hg and diastolic of 90 mm Hg during outpatient office visits; have your staff record the recheck in the patient’s medical records.
  • Educate your patients (and their spouses, caregivers or guardians) about the elements of a healthy lifestyle, such as:
    • Heart-healthy eating and low-salt diet.
    • Smoking cessation and avoiding secondhand smoke.
    • Adding regular exercise to daily activities.
    • Home BP monitoring.
    • Ideal body mass index.
    • The importance of taking all prescribed medications as directed.
  • Remember to include the applicable Category II reporting codes on the claim form to help reduce the burden of HEDIS medical record review.
Imtiaz Ahmad, MD, MPH, FCCP

Dr. Imtiaz Ahmad is a highly qualified physician, Board Certified in Pulmonary and Sleep Medicine. He has been actively serving the community of Lee County, Florida since 2004, with a strong focus on a proactive healthcare approach. Dr. Ahmad has received advanced training from some of the most prestigious institutions, including Harvard University, Cornell University, State University of New York at Brooklyn, and the University of Mississippi. SOMNAS is a medical facility that is committed to improving and maintaining the health of patients with sleep disorders. The expert team at SOMNAS is known for their compassionate and high-quality care. They offer unparalleled treatment and care to patients on the Gulf Coast of Florida, ensuring a better and healthier life for them.

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