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