Hypertension is one of the most common diagnoses in all of medicine — and one of the most consistently tested topics on the CPC exam. What makes it challenging is that hypertension rarely exists alone. It frequently co-exists with heart disease, heart failure, and chronic kidney disease, and ICD-10-CM has specific combination code rules for each combination. This guide walks through every hypertension scenario you need to master.
Hypertension Alone — I10
When a patient has hypertension with no documented heart disease, heart failure, or chronic kidney disease, coding is straightforward. ICD-10-CM uses a single code regardless of whether the hypertension is primary, essential, benign, or malignant — a major simplification from ICD-9-CM which had separate codes for each type.
The Four Hypertension Scenarios
Hypertension Only
Essential (primary) hypertension with no heart disease or CKD
HTN + Heart Disease
Hypertensive heart disease — a causal relationship is assumed by ICD-10-CM
HTN + CKD
Hypertensive chronic kidney disease — causal relationship assumed
HTN + Heart + CKD
Hypertensive heart and chronic kidney disease — all three present
Hypertension with Heart Disease — Category I11
When a patient has both hypertension and heart disease, ICD-10-CM presumes a causal relationship between the two — meaning it assumes the hypertension caused the heart disease — unless the physician specifically documents that the two conditions are unrelated. This is a critical assumption rule that simplifies coding but requires careful reading of documentation.
Category I11 has two subcategories based on whether heart failure is present:
- I11.0 — Hypertensive heart disease with heart failure
- I11.9 — Hypertensive heart disease without heart failure
When heart failure is present (I11.0), an additional code from category I50 must be added to specify the type of heart failure — systolic, diastolic, combined, or unspecified.
I50.30 — Unspecified diastolic (congestive) heart failure
The I11.0 code captures the hypertensive heart disease with heart failure. The I50 code is required as an additional code to specify the type of heart failure.
Hypertension with Chronic Kidney Disease — Category I12
Similar to heart disease, ICD-10-CM presumes a causal relationship between hypertension and CKD — the hypertension is assumed to have caused the kidney disease unless documented otherwise. Category I12 is used when both conditions are present:
- I12.9 — Hypertensive chronic kidney disease with stage 1 through stage 4 CKD, or unspecified CKD
- I12.1 — Hypertensive chronic kidney disease with stage 5 CKD or end stage renal disease (ESRD)
An additional code from category N18 is always required to specify the exact stage of CKD.
N18.3 — Chronic kidney disease, stage 3 (moderate)
The I12.9 code captures the hypertensive CKD relationship. N18.3 is mandatory as an additional code to identify the CKD stage.
Hypertension with Both Heart Disease and CKD — Category I13
When all three conditions are present — hypertension, heart disease, AND chronic kidney disease — category I13 is used. This is the most complex hypertension scenario and requires additional codes for both the heart failure type and the CKD stage:
| Code | Description | Additional Codes Required |
|---|---|---|
| I13.0 | Hypertensive heart and CKD with heart failure and stage 1–4 CKD | I50.– for heart failure type + N18.1–N18.4 for CKD stage |
| I13.10 | Hypertensive heart and CKD without heart failure, with stage 1–4 CKD | N18.1–N18.4 for CKD stage |
| I13.11 | Hypertensive heart and CKD without heart failure, with stage 5 or ESRD | N18.5 or N18.6 for CKD stage |
| I13.2 | Hypertensive heart and CKD with heart failure and stage 5 or ESRD | I50.– for heart failure type + N18.5 or N18.6 |
When the Relationship Is NOT Assumed — Separate Codes
The presumed causal relationship between hypertension and heart disease OR hypertension and CKD only applies when the physician has not documented that the conditions are unrelated. If the physician specifically documents that the heart disease or CKD is NOT caused by the hypertension — for example, “CKD due to polycystic kidney disease, unrelated to hypertension” — you code each condition separately using I10 for the hypertension and the appropriate heart disease or CKD code independently.