F01.C18
BillableVascular dementia, severe, with other behavioral disturbance
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F01.C18 an HCC code?
Yes. F01.C18 maps to Dementia, Severe under the CMS-HCC V28 risk adjustment model.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for F01.C18
For F01.C18 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed F01.C18 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F01.C18 is the ICD-10-CM diagnosis code for vascular dementia, severe, with other behavioral disturbance. Severe dementia caused by reduced blood flow to the brain, with behavioral problems other than agitation. F01.C18 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mental disorders due to known physiological conditions (f01-f09).
Under the CMS-HCC V28 risk adjustment model, F01.C18 maps to Dementia, Severe (HCC 125) with a community, non-dual, aged base RAF weight of 0.885. F01.C18 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Document the specific behavioral disturbance in detail (e.g., wandering, verbal outbursts, combativeness). Because F01.C18 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for F01.C18 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the specific behavioral disturbance in detail (e.g., wandering, verbal outbursts, combativeness)
- •Use this code only when behavioral disturbance is not agitation, psychotic, mood, or anxiety-related
Clinical Significance
Vascular dementia, severe, with other behavioral disturbance reflects cognitive decline due to cerebrovascular pathology, classified at the severe stage with behavioral disturbance other than agitation (e.g., wandering, sleep disturbance, hoarding, inappropriate social behavior). This condition indicates significant neurological impairment from vascular injury to brain tissue, often associated with stroke history, small vessel disease, or chronic cerebral hypoperfusion. Accurate staging and behavioral characterization are essential for care planning, safety assessments, and appropriate risk adjustment.
Documentation Requirements
- ✓Documentation must specify: (1) the dementia type and underlying etiology — The underlying cerebrovascular disease (such as multi-infarct dementia or subcortical vascular dementia) should be coded first, with the F01 code sequenced as an additional diagnosis.
- ✓(2) Severity must be clearly stated as severe based on standardized assessment tools such as the Clinical Dementia Rating (CDR) scale or Mini-Mental State Examination (MMSE).
- ✓(3) Document the specific behavioral disturbance type, such as wandering, sleep-wake cycle disruption, disinhibition, or repetitive behaviors.
- ✓(4) Document the impact on activities of daily living, need for supervision, and current medication management.
Use Additional Code
- code, if applicable, to identify wandering in vascular dementia (Z91.83)
Commonly Confused Codes
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