ICD-10 E66.2
Billable / Specific HCC v28: 22 CCMorbid (severe) obesity with alveolar hypoventilation
About ICD-10-CM E66.2
ICD-10-CM code E66.2 represents Morbid (severe) obesity with alveolar hypoventilation. This is a billable/specific code in the Endocrine, Nutritional, and Metabolic chapter (block E66). The 2026 edition of ICD-10-CM E66.2 became effective on October 1, 2025.
Coding Tips for E66.2
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
E66.2 is a CMS-HCC v28 risk-adjustment code (category 22). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
E66.2 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under E66.2. Per CMS ICD-10-CM Tabular 2026.
- Obesity hypoventilation syndrome (OHS)
- Pickwickian syndrome
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Morbid (severe) obesity with alveolar hypoventilation. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for E66.2
Local Coverage Determinations (LCDs) from CMS MACs that list E66.2 as a covered diagnosis.
Showing top 10 of 167 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing E66.2.
3 Aetna
2 Cigna
5 Medicare
CPT Codes Commonly Billed with E66.2
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 94660 CPAP initiation — acute/chronic respiratory failure, sleep apnea, COPD exacerbation, severe asthma, dyspnea, apnea, obesity hypoventilation Pulmonology
Convert E66.2 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| E66.2 | 27803 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To E66.2
Other codes in section E65-E68 (Overweight, obesity and other hyperalimentation).
ICD-10 E66.2, Billing FAQ
Is ICD-10 code E66.2 billable? +
Yes, E66.2 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to E66.2? +
ICD-10 E66.2 includes: Obesity hypoventilation syndrome (OHS); Pickwickian syndrome.
Does E66.2 affect Medicare Advantage HCC risk adjustment? +
Yes. E66.2 maps to CMS-HCC v28 category 22. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is E66.2 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with E66.2? +
Procedures frequently paired with E66.2 include: 94660.
What ICD-9 codes does E66.2 map to? +
Per CMS GEMs, E66.2 maps to ICD-9 codes: 27803. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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