2026 ICD-10-CM Diagnosis Code I50.33Acute on chronic diastolic (congestive) heart failure
ICD-10-CM Codes›I00–I99›I30-I5A›I50
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Risk Adjusts — HCC 224
- Chronic Condition
I50.33 is a billable ICD-10-CM diagnosis code for acute on chronic diastolic (congestive) heart failure. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 291 through 293, 791, 793. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 32 closely related codes. Coders also document this condition as acute diastolic heart failure. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Heart failure.
For Medicare Advantage risk adjustment, I50.33 maps to CMS-HCC Category 224 (Acute on Chronic Heart Failure) under the V28 model, adding a risk factor of about 0.360 for a community, non-dual, aged beneficiary in payment year 2026.
This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such heart failure.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
I50.33 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute diastolic heart failure
- Acute exacerbation of chronic heart failure
- Acute on chronic diastolic heart failure
- Chronic diastolic heart failure
- Diastolic heart failure
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Heart Failure
Heart failure means that your heart can't pump enough oxygen-rich blood to meet your body's needs. Heart failure doesn't mean that your heart has stopped or is about to stop beating. But without enough blood flow, your organs may not work well, which can cause serious problems.
The full article covers:
- What is heart failure?
- What causes heart failure?
- Who is more likely to develop heart failure?
- What are the symptoms of heart failure?
- What other problems does heart failure cause?
- How is heart failure diagnosed?
- What are the treatments for heart failure?
- Can heart failure be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I50.33 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I50.33Overview
What is the ICD-10 code for acute on chronic diastolic (congestive) heart failure?
The ICD-10-CM code for acute on chronic diastolic (congestive) heart failure is I50.33 (sometimes written as I5033). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is I50.33 (Diastolic (congestive) heart failure) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report acute on chronic diastolic (congestive) heart failure on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I50.33 group to?
When acute on chronic diastolic (congestive) heart failure is the principal diagnosis on an inpatient stay, it groups to MS-DRG 291, 292, 293, 791, 793, with relative weights from 0.5660 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.
Is I50.33 a CC or MCC?
CMS lists I50.33 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 32 closely related codes in its exclusion list.
What is the ICD-9 equivalent of I50.33?
Under the General Equivalence Mappings, acute on chronic diastolic (congestive) heart failure converts to ICD-9-CM 428.33 (ac on chr diast hrt fail), 428.33 (ac on chr diast hrt fail), and 428.0 (CHF NOS). The mapping is approximate, so confirm the match fits the documentation.
What HCC is I50.33?
I50.33 (acute on chronic diastolic (congestive) heart failure) maps to CMS-HCC Category 224 (Acute on Chronic Heart Failure), commonly written as HCC 224, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 85 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 186.
Does I50.33 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, I50.33 adds a risk adjustment factor of about 0.360 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.217 to 0.537 depending on the payment segment). A more severe related category (HCC 221, HCC 222, and HCC 223) supersedes it when both are reported. See the full factor table on the HCC 224 category page.
