Book excerpt: HCC basics

By Tracy Boldt, RN, BSN, CCDS, CDIP, and Ellen Jantzer, RN, MSN, CCDS, CCS, CRC

The hierarchical condition categories (HCC) are diagnosis code based on ICD-10 codes and include approximately 70 distinct disease groups derived from approximately 3,600 diagnosis codes that are mostly chronic but include some acute conditions, used primarily for outpatient services. The ICD-10 code book published by Optum includes the HCC designation along with CC/MCC. APCC and HCC University both have interactive tools to identify HCC codes.

The relationship between the ICD-10-CM diagnoses codes and the HCCs is one to many, meaning a single HCC may contain any number of ICD-10 diagnoses codes. Each HCC is assigned a relative factor or health risk score that is used to compute the patient’s risk adjustment factor. For example, HCC 21, Protein Calorie Malnutrition, includes:

• E41 Nutritional Marasmus
• E42 Marasmic Kwashiorkor
• E43 Unspecified Severe Protein Calorie Malnutrition
• E44.0 Moderate Protein Calorie Malnutrition
• E44.1 Mild Protein Calorie Malnutrition
• E45 Retarded Development following PCM
• E46 Unspecified Protein Calorie Malnutrition
• E64.0 Sequelae of Protein Calorie Malnutrition
• R64 Cachexia or Wasting Syndrome

Not all ICD-10-CM codes are reflected in HCC groupings; CMS identified diagnoses which:

• Are related to high costs
• Complicate coordination of care
• Increase potential care needs or medications

The list of such diagnoses and their corresponding HCC is updated annually by CMS and can be found here.

The basic HCCs categories include:

• Infection
• Neoplasm
• Diabetes
• Cerebrovascular disease
• Vascular
• Lung
• Metabolic
• Liver
• Gastrointestinal
• Musculoskeletal
• Eye
• Kidney
• Openings
• Amputations
• Blood
• Substance abuse
• Skin
• Injury
• Psychiatric
• Spinal
• Neurological
• Arrest
• Heart
• Complications
• Transplants

The ultimate payment is per HCC (not per diagnosis code), similar to the DRG system on the inpatient side, and is based on the highest-rated HCC within a category.

Editor’s note: This is an excerpt from The Outpatient CDI Specialist’s Complete Training Guide.