Hypertension is a common condition and you can see this condition documented in most of the medical records by the physicians. Therefore it is essential to keep updated with the coding guidelines of hypertension for accurate coding.Hypertension can occur with heart disease, chronic kidney disease (CKD) or both. Categories I10-I13 classifies primary hypertension according to a hierarchy of the disease from its vascular origin (I10) to the involvement of the heart (I11), CKD (I12), or heart and CKD combined (I13).Figure: Hypertension combination codes:
A detailed review on Primary and secondary hypertension is provided in the below link:
Hypertension with heart disease: I11
Hypertension with heart conditions classified to I50 or I51.4-I51.9, are assigned to a code from category I11, Hypertensive heart disease. Category I11 is subdivided to indicate whether heart failure is present. Therefore an additional code from category I50 is required to specify the type of heart failure, if known.
ICD-10 CM presumes a causal relationship between hypertension and heart involvement. These conditions should be coded as related even in the absence of provider documentation linking both the conditions.
A patient is admitted with left heart failure. Patient also has hypertension and managed by the medications.
I11.0 Hypertensive heart disease with heart failure
I50.1 Left ventricular failure, unspecified
Rationale: ICD-10 CM presumes a causal relationship between hypertension and heart condition. Therefore combination code I11 is used and additional codes are assigned to indicate the type of heart failure.
When the provider specifically documents different causes for the hypertension and the heart condition, in such cases, the heart conditions (I50.-, I51.4-I51.7, I51.89, and I51.9) and hypertension are coded separately. The code sequence will depend on the circumstances of the admission or encounter.
Hypertensive Chronic kidney disease: I12
Category I12 should be assigned whenever CKD and hypertension occur together even if there is no causal relationship documented. Category I12 is subdivided based on the stages of chronic kidney disease. Therefore an additional code to identify the stages of CKD should also be assigned.
ICD-10 CM presumes a cause-and-effect relationship and classifies CKD with HTN as hypertensive CKD. The appropriate code from category N18 should be used as a secondary code to identify the stage of CKD.
CKD should not be coded as hypertensive if the provider clearly indicates the CKD is not related to the hypertension. In such cases, both the conditions are coded separately.
Patient is admitted with stage IV CKD due to polycystic kidney disease. Patient is also under medications for hypertension.
N18.4 Chronic kidney disease, stage 4
Q61.3 Polycystic kidney, unspecified
Rationale: In this case example, it is specifically documented that CKD is due to kidney disease and not due to hypertension. Therefore the combination code I12 is not assigned for this case and separate codes are assigned as above.
Hypertensive heart and CKD (I13):
The codes in category I13, hypertensive heart and CKD, are combination codes that include
- Heart disease
- Chronic kidney disease
Category I13 should be assigned when there is hypertension with both heart and kidney involvement. The conditions included in I11 and I12 are also present within category I13. Therefore if a patient has hypertension, heart disease and CKD, then a code from category I13 should be used and not the individual codes for hypertension, heart disease and CKD or codes from category I11 or 12.
Category I13 codes require additional codes for a complete code assignment.
- Assign additional code from category I50 to identify the type of heart failure.
- Assign additional codes from category N18 to identify the stage of CKD. In patients with both acute renal failure and CKD, an additional code for acute renal failure is also required.
A patient admitted with hypertensive heart and kidney disease with congestive heart failure and stage 2 chronic kidney disease.
I13.0 Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
I50.9 Heart failure, unspecified
N18.2 Chronic kidney disease, stage 2 (mild)
Rationale: Category I13 is used to report the conditions classifiable to both categories I11 and I12. Additional codes are used to report the type of heart failure and the stage of CKD.
Table: Hypertension category codes
Happy learning! Happy Coding!