I1A.0 ICD-10-CM Code: Resistant hypertension

Code

I1A.0

Description

Resistant hypertension

HCC (V28)

No CMS-HCC V28 mapping

RAF reference coefficient

—

Billable

Yes

Payment year

2026

HCC Category Mapping

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work I1A.0 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for I1A.0

What This Code Means

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for I1A.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

• •Document the specific medications tried, their doses, and duration of treatment to support this diagnosis
• •Code any secondary causes of hypertension separately, as resistant hypertension may be secondary to an underlying condition

Clinical Significance

Resistant hypertension is defined as blood pressure that remains above goal despite concurrent use of three or more antihypertensive agents of different classes at optimal doses, one of which should be a diuretic. This is a relatively new ICD-10-CM code that captures a clinically distinct subset of hypertension associated with higher cardiovascular risk and greater healthcare resource utilization.

Documentation Requirements

• ✓Provider explicitly documenting resistant hypertension as the diagnosis
• ✓Documentation of three or more antihypertensive medications from different classes at optimal doses
• ✓At least one medication should be a diuretic
• ✓Blood pressure readings demonstrating failure to achieve target despite treatment
• ✓Assessment for secondary causes of hypertension (often performed in resistant cases)
• ✓Medication adherence assessment
• ✓Documentation ruling out pseudo-resistance (white coat effect, medication non-adherence)

Commonly Confused Codes

• •I10: Essential hypertension (use for standard hypertension controlled or not yet meeting resistant criteria)
• •I15.x: Secondary hypertension (resistant hypertension has no identified secondary cause; if a cause is found, use I15.x)
• •I16.0: Hypertensive urgency (acute severe elevation, different from chronic resistance to treatment)
• •I16.1: Hypertensive emergency (acute with organ damage, different from chronic resistance)

Child Codes