ICD-10 Coding for Hypertension Associated with Chronic Kidney Disease
The ICD-10 code for hypertension associated with chronic kidney disease is I12, with the fourth digit specifying the presence or absence of kidney failure and the fifth digit indicating the stage of CKD.
Primary Code Structure
The coding follows a hierarchical system that captures both the hypertensive disease and the kidney involvement 1:
- I12.0 - Hypertensive chronic kidney disease with stage 5 CKD or end-stage renal disease
- I12.9 - Hypertensive chronic kidney disease with stage 1 through stage 4 CKD, or unspecified CKD
Essential Coding Requirements
You must use an additional code from category N18 to identify the specific CKD stage 1:
- 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
Critical Coding Assumption
ICD-10 assumes a causal relationship between hypertension and CKD when both conditions are present, unless documentation explicitly states they are unrelated 1. This means you should code I12 rather than separate codes for essential hypertension (I10) and CKD (N18) when both conditions coexist.
Common Coding Pitfalls to Avoid
- Do not code I10 (essential hypertension) separately when hypertensive CKD is present - the relationship is presumed 1
- Always include the N18 code to specify CKD stage - the I12 code alone is insufficient 1
- For stage 5 CKD or ESRD, use I12.0 specifically, not I12.9 1
- If the provider documents that hypertension and CKD are unrelated, then code them separately as I10 and N18.x 1
Clinical Context for Accurate Coding
The diagnosis requires documentation of both elevated blood pressure (≥140/90 mmHg) and evidence of kidney dysfunction, defined as eGFR <60 mL/min/1.73 m² or albuminuria ≥30 mg/g for at least 3 months 1. Hypertension affects 67-92% of patients with CKD, with prevalence increasing as kidney function declines 1.