Hypertension is high blood pressure and a major health problem found in Americans, especially the elderly. This is a serious condition since hypertension is a risk factor for heart disease and other medical problems. If proper treatment is not given, this condition can lead to health concerns such as arteriosclerosis, heart attack, stroke, enlarged heart and kidney damage. It is very important for physicians to report this condition correctly with appropriate diagnosis codes. As ICD-10 implementation is near, it is time to focus on the new codes used for hypertension.
Unlike ICD-9, there is limited number of hypertension codes in ICD-10. The ICD-10 medical coding for hypertension is relatively simpler compared to other complexities.
Primary Hypertension
In ICD-9, primary or essential hypertension is coded according to the severity of hypertension, malignant (401.0), benign (401.1) or unspecified (401.9). In ICD-10, there is only a single code for primary hypertension without co-morbid heart or kidney disease.
- I10:Essential (primary) hypertension
Hypertension and Associated Conditions
If a patient with hypertension is confirmed to have co-morbid heart and/or kidney disease, it should be reported using ICD-10 codes in the following manner.
Hypertension and Heart Disease
In case of ICD-9, this category is divided into malignant, benign, and unspecified essential hypertension with or without heart failure. There are only two codes for the same condition in ICD-10 such as:
- I11.0:Hypertensive heart disease with heart failure
- I11.9:Hypertensive heart disease without heart failure
Unlike ICD-9, it is required to report the type of heart failure using the codes from I50 series while coding hypertension with heart failure (I11.0). The codes that are used to specify the type of heart failure are as follows.
- I50.1:Left ventricular failure
- I50.2:Systolic (congestive) heart failure
- I50.3:Diastolic (congestive) heart failure
- I50.4:Combined systolic and diastolic heart failure
- I50.9:Heart failure, unspecified
The codes for systolic, diastolic and combined failure require a fifth digit to specify the acuity of the diagnosis:
- 0 – Unspecified
- 1 – Acute
- 2 – Chronic
- 3 – Acute on chronic
You would need to use the general left ventricular failure code (I50.1) in case of not having a measurement of the left ventricular ejection fraction (typically from an echocardiogram).
Hypertension and Chronic Kidney Disease
If the patient has hypertension and then develops chronic kidney disease, ICD-10 will consider that condition as hypertensive chronic kidney disease. However, if the chronic kidney disease came first and then the combination, their codes fall under the secondary hypertension codes. In the case of hypertensive kidney disease, both ICD-9 and ICD-10 require specifying the stage of the kidney disease while ICD-10 distinguishes stage 5 from end-stage renal disease by the need of chronic dialysis.
First use I12 code to report the combined diagnosis of hypertension and chronic kidney disease.
- I12.0:Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end-stage renal disease
- I12.9:Hypertensive chronic kidney disease with stage 1 through 4 chronic kidney disease or unspecified chronic kidney disease
Both these codes require an additional N18 code to specify the stage of kidney disease.
- N18.1:Chronic kidney disease, stage 1
- N18.2:Chronic kidney disease, stage 2 (mild)
- N18.3:Chronic kidney disease, stage 3 (moderate)
- N18.4: Chronic kidney disease, stage 4 (severe)
- N18.5:Chronic kidney disease, stage 5
- N18.6: End-stage renal disease
- N18.9: Chronic kidney disease, unspecified
Hypertension, Heart Disease and Chronic Kidney Disease
The ICD-10 codes for the three-disease combination (if the patient has all the three conditions, hypertension, heart disease and chronic kidney disease) are classified according to the degree of chronic kidney disease rather than the presence or absence of heart failure.
- I13.0: Hypertensive heart and chronic kidney disease with heart failure and with stage 1 through 4 chronic kidney disease, or unspecified chronic kidney disease
- I13.10: Hypertensive heart and chronic kidney disease without heart failure with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
- I13.11:Hypertensive heart and chronic kidney disease without heart failure with stage 5 chronic kidney disease, or end-stage renal disease
- I13.2: Hypertensive heart and chronic kidney disease with heart failure and with stage 5 chronic kidney disease, or end-stage renal disease
Just as the two-disease combination codes, these codes require additional codes from the N18 series to specify the stage of kidney disease. Additional medical coding from the I50 series is also required for these three-combination codes to specify the type and acuity of the heart failure.
Coding for Tobacco Use or Exposure
An additional ICD-10 code is required for all hypertension codes if the patient uses tobacco currently or had used it earlier. The codes for tobacco use are:
- F17: Nicotine dependence
- F17.20: Unspecified
- F17.21: Cigarettes
- F17.22:Chewing tobacco
- F17.29:Other tobacco product
Each of these four categories requires a sixth character:
- 0 – uncomplicated
- 1 – in remission
- 3 – with withdrawal
- 8 – with other specified nicotine-induced disorder
- 9 – with unspecified nicotine-induced disorder
If you find that occupational and environmental exposure to tobacco is influencing the health status of your patient, report that using the following ICD-10 codes:
- Z57.31:Occupational exposure to environmental tobacco smoke
- Z72.0: Problems related to lifestyle, tobacco use
- Z77.22:Exposure to environmental tobacco smoke (includes second-hand smoke exposure and passive smoking)
- Z87.891:Personal history of nicotine dependence
Secondary Hypertension
The above mentioned ICD-10 codes are not used in the case of patients having hypertension secondary to other diseases. The secondary hypertension codes are used in such a situation, which include:
- I15.0: Renovascular hypertension
- I15.1: Hypertension secondary to other renal disorders
- I15.2: Hypertension secondary to endocrine disorders
- I15.8: Other secondary hypertension
- I15.9: Secondary hypertension, unspecified
Code the underlying condition also when reporting secondary hypertension. ICD-10 allows listing either the underlying condition or the secondary hypertension code as first depending on the reason for the patient encounter. However, in the case of I15.8, the ‘other’ condition must be coded first.
Other Hypertension Codes
- I27.0: Other primary pulmonary hypertension (Primary hypertension NOS)
- I27.2: Other secondary pulmonary hypertension (Code also associated underlying condition)
- I27.89: Other specified pulmonary heart diseases
- R03.0: Elevated blood-pressure reading, without diagnosis of hypertension
The code R03.0 should be used to indicate an episode of elevated blood pressure in a patient when no formal diagnosis of hypertension has been made, or as an incidental finding.
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