ICD-10 Codes for Type 2 Diabetes — Complete 2026 Guide

Overview of ICD-10 Diabetes Codes

Diabetes mellitus is one of the most coded conditions in healthcare. The ICD-10-CM classification contains hundreds of diabetes codes organized into categories based on the type of diabetes and its associated complications and manifestations. Accurate diabetes coding is essential for quality reporting, HCC risk adjustment, and claim reimbursement.

The main diabetes categories in ICD-10-CM are:

• E08 — Diabetes mellitus due to underlying condition
• E09 — Drug or chemical induced diabetes mellitus
• E10 — Type 1 diabetes mellitus
• E11 — Type 2 diabetes mellitus
• E13 — Other specified diabetes mellitus

Type 2 diabetes (E11) is by far the most common — affecting approximately 90-95% of all people with diabetes in the United States.

Type 2 Diabetes — Core Codes (E11)

Diabetic Eye Complications (E11.3-)

Diabetic eye disease is a leading cause of blindness in adults. When coding diabetic eye complications, coders must specify the type of eye condition, the affected eye(s), and the severity where applicable.

Code	Description
E11.311	Type 2 diabetes with unspecified diabetic retinopathy with macular edema
E11.319	Type 2 diabetes with unspecified diabetic retinopathy without macular edema
E11.331	Type 2 diabetes with moderate nonproliferative retinopathy with macular edema
E11.351	Type 2 diabetes with proliferative retinopathy with macular edema
E11.36	Type 2 diabetes with diabetic cataract
E11.39	Type 2 diabetes with other diabetic ophthalmic complication

HCC Impact of Diabetes Coding Specificity

For Medicare Advantage and risk adjustment purposes, the specificity of your diabetes code directly determines the HCC category and RAF score. This has significant financial implications:

Code	Description	HCC Category	RAF Score
E11.9	Type 2 diabetes without complications	HCC17	0.105
E11.65	Type 2 diabetes with hyperglycemia	HCC17	0.105
E11.40	Type 2 diabetes with neuropathy	HCC18	0.302
E11.21	Type 2 diabetes with nephropathy	HCC18	0.302
E11.10	Type 2 diabetes with ketoacidosis	HCC19	0.318

A patient coded with E11.40 (diabetic neuropathy) generates almost 3x the risk adjustment payment compared to E11.9 (diabetes without complications), when the neuropathy is clinically documented. This is why accurate and specific diabetes coding is a priority in Medicare Advantage coding programs.

Diabetes Sequencing Rules

Important sequencing rules apply to diabetes codes:

• Diabetes is always the etiology — when a diabetic complication is coded, the diabetes code is sequenced first, followed by the complication code if an additional code is needed
• Do not code E11.9 with a complication code — if you are coding a specific complication (E11.21, E11.40, etc.), do not also add E11.9
• Multiple complications — when a patient has multiple diabetic complications, code each applicable complication code
• Insulin use — when a Type 2 diabetic patient uses insulin, add code Z79.4 (long-term current use of insulin) as an additional code
• Oral hypoglycemic agents — add Z79.84 when the patient uses oral hypoglycemic drugs

Annual Recapture for HCC

One of the most common HCC coding gaps involves diabetes. For Medicare Advantage risk adjustment, diabetes complications must be documented and coded every year to maintain the HCC. A patient with diabetic neuropathy coded in 2025 but not coded in 2026 loses the HCC17/18 credit for that plan year.

Annual wellness visits, chronic care management encounters, and specialist visits are all opportunities to capture and code active diabetic complications for HCC recapture purposes.