Charlson Comorbidity Index

The Charlson Comorbidity Index is a method of classifying prognostic comorbidity in longitudinal studies.

Indicators
Indicator:	Charlson Comorbidity Index
Created/Raw:	Created
Program:	Critical Care and Medicine
Start Date:	1998-09-14
End Date:
Reports:	Directors Quarterly and Annual Report (Medicine)

• Cargo

• SMW:

• Categories

• Default form:

Some Comorbid Diagnosis have points associated with them that contribute to an overall comorbidity score. This score reflects the cumulative increased likelihood of one year mortality.

Structure

• The CCI takes account of 17 chronic medical conditions

• Each of the 17 items has a certain number of points, and the total score is the sum of all of them.
  • There is one tricky thing about the scoring though:
    • Of the 17 there are two are mutually exclusive pairs: (a) Diabetes Mellitis with and without chronic complications, and (b) Liver disease as mild vs. moderate/severe. If you should qualify for both members of a pair, then only count the points for the more severe (higher scoring). Example: if you have diagnoses that qualify you for both mild liver disease and moderate/severe liver disease, only include the points from the latter.
• For a list of all diagnosis applicable that we use go to: Charlson Comorbid Diagnosis (or Charlson Comorbid coding (pre ICD10)#Comorbid_List as former may not include all sub-diagnoses).

Derivation

• the actual score: query Charlson_Score_pre_and_ICD10
• ICD10 (includes all admission having Dispo DtTm starting Jan 1, 2019)
  • Charlson Comorbidities in ICD10 codes
  • Charlson Comorbidity scoring in ICD10 codes
• pre-ICD10 (includes all admissions having Dispo DtTm before Jan 1, 2019)
  • Charlson Comorbidity scoring in pre-ICD10 codes

Data Use

• ALERT Scale score for Medicine
• Some items are use for APACHE II score for Critical Care. For a specific list of chronic condition applicable to APACHE II scoring see: Chronic Health APACHE

Background

The Charlson Index was developed in 1987 based on 1-year mortality data from internal medicine patients admitted to a single New York Hospital and was initially validated within a cohort of breast cancer patients. The index encompasses 19 medical conditions weighted 1–6 with total scores ranging from 0–37. In the development phase of the index, mortality for each disease was converted to a relative risk of death within 12 months. A weight was then assigned to each condition based on the relative risk (RR); for example,

• RR <1.2 = weight 0,
• RR ≥ 1.2<1.5 = weight 1,
• RR ≥ 1.5<2.5 = weight 2,
• RR ≥ 2.5<3.5 = weight 3,
• and for 2 conditions (metastatic solid tumor and AIDS) = weight 6.

From the weighted conditions, a sum score can be tallied to yield the total comorbidity score.

Article and related publications

• "A new method of classifying prognostic comorbidity in longitudinal studies: development and validation" ME Charlson
  • PDF of article (also: A PDF of the complete original article can be found on- X:\CCMDB_ADMIN_DATABASE\Charlson_Comorbids\OriginalCharlsonArticlePDF)
  • image of Charlson article, page 2.

• Article: An electronic application for rapidly calculating Charlson comorbidity score. Article with link to a comorbid score calculator developed in MS Excel using a macro.
  • Copy of this calculator can be found: X:\CCMDB_ADMIN_DATABASE\Charlson_Comorbids\comorbid calculator

• "Coding algorithms for defining comorbidities in ICD-9-CM and ICD-10 administrative data" Hude Quon

• MCHP Resources:
  • SAS code to convert IC10 to Charlson
  • Deyo and Quon Charlson ranges

Legacy

See Category:Charlson Comorbid Diagnosis (pre ICD10) for how Charlson was calculated before ICD10.