Diabetes Mellitus (Type 2) HCC Coding Guide
Diabetes Mellitus (Type 2) (e.g. E11.9) maps to HCC 38 (Diabetes with No, Glycemic, or Unspecified Complications) under the CMS-HCC V28 risk adjustment model, with a community, non-dual, aged RAF weight of 0.166; V28 reached 100% phase-in for payment year 2026. E11.22, type 2 diabetes mellitus with diabetic chronic kidney disease, is non-HCC under V28. It can also map to HCC 383 (Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle) and HCC 298 (Severe Diabetic Eye Disease, Retinal Vein Occlusion, and Vitreous Hemorrhage) when the documentation supports those manifestations.
Complete HCC coding guide for Type 2 Diabetes Mellitus (E11.x) including ICD-10 to HCC mapping, V28 RAF weights, documentation tips, and common coding mistakes.
Medically reviewed by Jess P., CPC · Reviewed: May 9, 2026 · Updated for CMS-HCC V28 and FY2026 ICD-10-CM
Quick Facts
HCC Categories
HCC 383, Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle
HCC 298, Severe Diabetic Eye Disease, Retinal Vein Occlusion, and Vitreous Hemorrhage
HCC 38, Diabetes with No, Glycemic, or Unspecified Complications
HCC 37, Diabetes with Chronic Complications
RAF Weight Range
0.166 to 0.646
Community, non-dual, aged (V28)
Model
CMS-HCC V28 (PY2026, 100% phase-in)
5 ICD-10 codes map to payment HCCs
What HCC category does Diabetes Mellitus (Type 2) map to under V28?
Type 2 diabetes mellitus is one of the highest-impact conditions in HCC risk adjustment, affecting over 37 million Americans. Under the CMS-HCC V28 model, the E11 codes split into two diabetes categories: uncomplicated, glycemic, or unspecified diabetes maps to HCC 38, while diabetes with chronic complications maps to HCC 37. A key point coders miss is that many E11 manifestation codes carry a second HCC on top of the diabetes category. Severe diabetic eye disease (proliferative retinopathy) also maps to HCC 298, and a diabetic foot or skin ulcer also maps to HCC 383. Accurate coding means documenting the diabetes type, the causal link to each manifestation, and the treatment plan so every applicable HCC is captured.
ICD-10 to HCC Mapping
| ICD-10 Code | Description | Billable | HCC Mapping |
|---|---|---|---|
| E11.9 | Type 2 diabetes mellitus without complications | Yes | HCC 38 |
| E11.65 | Type 2 diabetes mellitus with hyperglycemia | Yes | HCC 38 |
| E11.22 | Type 2 diabetes mellitus with diabetic chronic kidney disease | Yes | No HCC (not risk-adjusting under V28) |
| E11.40 | Type 2 diabetes mellitus with diabetic neuropathy, unspecified | Yes | No HCC (not risk-adjusting under V28) |
| E11.311 | Type 2 diabetes mellitus with unspecified diabetic retinopathy with macular edema | Yes | HCC 298 |
| E11.51 | Type 2 diabetes mellitus with diabetic peripheral angiopathy without gangrene | Yes | No HCC (not risk-adjusting under V28) |
| E11.621 | Type 2 diabetes mellitus with foot ulcer | Yes | HCC 383 |
| E11.69 | Type 2 diabetes mellitus with other specified complication | Yes | HCC 37 |
| E11.21 | Type 2 diabetes mellitus with diabetic nephropathy | Yes | No HCC (not risk-adjusting under V28) |
| E11.42 | Type 2 diabetes mellitus with diabetic polyneuropathy | Yes | No HCC (not risk-adjusting under V28) |
RAF weights are community, non-dual, aged base coefficients from the CMS-HCC V28 model (PY2026). Verify against the latest CMS rate announcement for payment calculations.
HCC Buddy maps Diabetes Mellitus (Type 2) from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Documentation Tips
Always document the specific type of diabetes (Type 1, Type 2, or secondary), never code 'unspecified diabetes' when the type is known.
Document causal relationships between diabetes and complications (e.g., 'diabetic nephropathy' vs. 'nephropathy in a patient with diabetes').
Use combination codes from E11 for diabetes with complications rather than coding diabetes and complications separately.
Specify laterality for diabetic retinopathy and severity of macular edema when applicable.
Document current HbA1c level and whether hyperglycemia or hypoglycemia is present at the encounter.
Record all active diabetic complications at every encounter, do not rely on problem list carry-forward without provider attestation.
Document the treatment plan including medications, insulin use, and monitoring frequency to satisfy MEAT criteria.
Common Coding Mistakes
Coding E11.9 (without complications) when the patient has documented diabetic complications, always code to the highest specificity.
Failing to link diabetes as the cause of kidney disease, neuropathy, or retinopathy when the provider has documented the causal relationship.
Using unspecified diabetes codes (E13.x) instead of Type 2 (E11.x) when the type is clearly documented.
Missing the opportunity to code diabetic chronic kidney disease (E11.22) alongside the specific CKD stage code.
Not capturing hyperglycemia (E11.65) when the encounter note documents elevated blood glucose or uncontrolled diabetes.
V24 to V28 Changes
V28 reorganized the diabetes hierarchy into HCC 37 (Diabetes with Chronic Complications) and HCC 38 (Diabetes with No, Glycemic, or Unspecified Complications). Both currently carry the same community RAF of 0.166, so unlike prior models V28 does not reward a complicated diabetes code over an uncomplicated one at the diabetes category alone. The real lift now comes from the separate manifestation HCCs an E11 code can trigger: severe diabetic eye disease adds HCC 298 (RAF 0.336) and a diabetic skin or foot ulcer adds HCC 383 (RAF 0.646), each additive on top of the diabetes HCC. The lesson for coders is to capture every documented manifestation, not just the base diabetes code.
Related Conditions
Related references
Sources
RAF weights are community, non-dual, aged base coefficients from the CMS-HCC V28 model (PY2026). Verify against the latest CMS Rate Announcement for payment.
Verified current to CMS-HCC V28, payment year 2026 — last reviewed May 9, 2026.
Look up Diabetes Mellitus (Type 2) codes instantly
HCC Buddy gives you instant ICD-10 to HCC mapping with RAF weights, documentation tips, and Ask Buddy for Diabetes Mellitus (Type 2) and 72,000+ other codes.
Get HCC coding tips in your inbox
Weekly updates on coding guidelines, V28 changes, and documentation best practices for risk adjustment professionals.