E66.1 ICD-10-CM Code: Drug-induced obesity
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Overweight, obesity and other hyperalimentation (E65-E68)
E66.1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceDrug-induced obesity
Weight gain and obesity caused as a side effect of medications.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for E66.1 in this effective period.
Excludes 2
Official- adiposogenital dystrophy (E23.6)
- lipomatosis dolorosa [Dercum] (E88.2)
- lipomatosis NOS (E88.2)
- Prader-Willi syndrome (Q87.11)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E66.1 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for E66.1 in this effective period.
Code First
Official- obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)
Use Additional
Official- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
Code Also
OfficialICD-10-CM does not list Code Also instructions for E66.1 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is E66.1 an HCC code?
No. E66.1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- E66.1
- Description
- Drug-induced obesity
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
E66.1 is the ICD-10-CM diagnosis code for drug-induced obesity. Weight gain and obesity caused as a side effect of medications. E66.1 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering overweight, obesity and other hyperalimentation (e65-e68).
E66.1 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Drug-induced obesity, obesity specifically attributed by the provider to a medication (common offenders: antipsychotics, corticosteroids, insulin, some anticonvulsants). Provider must document the causal relationship.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E66.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Drug-induced obesity, obesity specifically attributed by the provider to a medication (common offenders: antipsychotics, corticosteroids, insulin, some anticonvulsants). Provider must document the causal relationship.
- •Do not assume drug-induced obesity from medication lists alone, the provider must make the etiologic link. Without that documentation, E66.09 (or E66.01 if morbid) is the correct code.
- •E66.1 does not map to a V28 payment HCC. Chart completeness code only.