Table 1.

Characteristics of Chronic Condition Classification Measures

	Chronic Condition Data Warehouse (CCW)	Charlson Comorbidity Index (CCI)	Johns Hopkins Adjusted Clinical Groups® (ACG®) Case-Mix Systema	Medicare Advantage Special Needs Plan Chronic Conditions (c-SNP)
Total Possible Chronic Conditions (n)	21 (19 for men, 20 for women)	17	119	15
Timeframe	Total years of Medicare enrollment	1 year	1 year	1 year
Original Purpose	Prevalence/Cohort Identification for Research Purposes	Mortality Prediction	Prevalence/Cohort Identification for Research Purposesa	Select Medicare Advantage beneficiaries eligible for enhanced clinical services
Reference	Centers for Medicare and Medicaid Services (2005)	Klabunde et al (2000)	Johns Hopkins University (2009)	Pope et al (2011), Centers for Medicare and Medicaid Servicesb

^aExpanded Diagnoses Clusters™ (EDCs™) are intended to be used for investigating the epidemiology of diseases within populations in contrast to the Johns Hopkins Adjusted Clinical Groups® Case-Mix System Aggregated Diagnosis Groups™ (ADGs®), which are actuarial cells designed for risk prediction modeling that include information about condition duration, severity, diagnostic certainty, etiology, and specialty care required.

^bThe c-SNPs were derived from Hierarchical Condition Categories (HCCs) (version 22) using a previously published strategy for deriving c-SNPs from version 12 HCCs.¹⁶ We used the Taylor Flag³⁴ for dementia since dementia is a c-SNP condition that does not have an equivalent HCC in the HCC community claims model. The 15 c-SNP conditions are currently being used by Medicare Advantage health insurance plans to identify beneficiaries eligible for enhanced care coordination services via physician verification of eligibility criteria rather than from claims data algorithms.²¹