Charlson Comorbidity Index

In medicine, the Charlson Comorbidity Index (CCI) predicts the mortality for a patient who may have a range of concurrent conditions (comorbidities), such as heart disease, AIDS, or cancer (considering a total of 17 categories).^[1] A score of zero means that no comorbidities were found; the higher the score, the higher the predicted mortality rate and the lower the predicted ten-year survival.^[2][3] For a physician, this score is helpful in deciding how aggressively to treat a condition.

It is one of the most widely used scoring system for comorbidities.^[4] The index was developed by Mary Charlson and colleagues in 1987, but the methodology has been adapted several times since then based on the findings of additional studies.^[5] Many variations of the Charlson comorbidity index have been presented, including the Charlson/Deyo, Charlson/Romano, Charlson/Manitoba, and Charlson/D'Hoores comorbidity indices.

Calculation

Each condition is assigned a score of 1, 2, 3, or 6, depending on the risk of dying associated with each one. Clinical conditions and associated scores are as follows:

• 1 each: Myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, rheumatologic disease, peptic ulcer disease, liver disease (if mild, or 3 if moderate/severe), diabetes (if controlled, or 2 if uncontrolled)
• 2 each: Hemiplegia or paraplegia, renal disease, malignancy (if localized, or 6 if metastatic tumor), leukemia, lymphoma
• 6 each: AIDS

Patients who are 50 years old or more get additional points:^[6]

• 50-59 years old: +1 point
• 60-69 years old: +2 points
• 70-79 years old: +3 points
• 80 years old or more: +4 points

Scores are summed to provide a total score to predict mortality.

Currently 17 categories are considered in the popular Charlson/Deyo variant,^[7] instead of 19 in the original score.^[8] The weights were also adapted in 2003.^[9]

Conditions can be identified using the International Classification of Diseases (ICD) diagnosis codes commonly used in patient records.

Use

For a physician, this score is helpful in deciding how aggressively to treat a condition. For example, a patient may have cancer with comorbid heart disease and diabetes. These comorbidities may be so severe that the costs and risks of cancer treatment would outweigh its short-term benefit.

Since patients often do not know how severe their conditions are, nurses were originally supposed to review a patient's chart and determine whether a particular condition was present in order to calculate the index. Subsequent studies have adapted the comorbidity index into a questionnaire for patients.

The Charlson index, especially the Charlson/Deyo, followed by the Elixhauser have been most commonly referred by the comparative studies of comorbidity and multimorbidity measures.^[10]

See also

• Comorbidity
• Comorbidity–polypharmacy score (CPS)
• Elixhauser Comorbidity Index