E66.2 Morbid (severe) obesity with alveolar hypoventilation

The ICD-10-CM code for Morbid (severe) obesity with alveolar hypoventilation is E66.2 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

4: Endocrine, nutritional and metabolic diseases (E00-E89)

Section

E65-E68: Overweight, obesity and other hyperalimentation (E65-E68)

Category E66

14 codes (10 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to E66.2:

• OHS (obesity hypoventilation syndrome)
• Pickwickian syndrome
• Obesity › with alveolar hypoventilation
• Syndrome › hypoventilation, obesity (OHS)
• Syndrome › obesity hypoventilation (OHS)
• Obesity › hypoventilation syndrome (OHS)
• Syndrome › alveolar hypoventilation
• Syndrome › cardiopulmonary-obesity

Inclusion Terms

• Obesity hypoventilation syndrome (OHS)
• Pickwickian syndrome

U.S. Hospital Utilization

• An estimated 209,300 U.S. inpatient stays in 2023 included E66.2 among the documented diagnoses.
• 5,845 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

E66 obesity codes include causes/effects; other obesity codes exist

b. Obesity The obesity codes in category E66, Overweight and obesity, include codes related to the cause of obesity, such as drug-induced obesity (E66.1), and codes related to effects of obesity, such as code E66.2, Morbid (severe) obesity with alveolar hypoventilation. There are other codes related to obesity in other categories of the classification, such as E88.82, Obesity due to disruption of MC4R pathway; and codes in fifth character subcategory O99.21, Obesity complicating pregnancy, childbirth, and the puerperium.

Diabetes mellitus (TOC entry)

a. Diabetes mellitus ................................................................................................................... 39

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)