The Charlson Comorbidity Index (CCI) is a tool used to predict a patient's 10-year survival by taking into account age and various medical conditions. Each component of the index is assigned a score based on the presence or absence of specific conditions and the patient's age. These scores are then summed to produce a total CCI score, which provides an estimate of long-term survival.

- Age is scored as:
  - Less than 50 years: 0 points
  - 50 to 59 years: 1 point
  - 60 to 69 years: 2 points
  - 70 to 79 years: 3 points
  - 80 years or older: 4 points

- Medical conditions are scored as follows:
  - Myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, connective tissue disease, and ulcer disease each contribute 1 point if present.
  - Liver disease scores 0 for none, 1 for mild chronic hepatitis or cirrhosis without portal hypertension, and 3 for moderate to severe cirrhosis with or without variceal bleeding.
  - Diabetes mellitus contributes 0 points if absent, 1 point for uncomplicated diabetes, and 2 points for diabetes with end-organ damage.
  - Hemiplegia and moderate to severe chronic kidney disease each add 2 points if present.
  - Solid tumors add 0 points if absent, 2 points if localized, and 6 points if metastatic.
  - Leukemia and lymphoma each contribute 2 points if present.
  - AIDS contributes 6 points if present.

The CCI score is the sum of these individual scores and can range from 0 to 37. The total score correlates with an estimated 10-year survival probability, which is interpreted as follows:

- A score of 0 suggests an estimated 10-year survival rate of 98%.
- A score of 1 corresponds to a 96% survival rate.
- A score of 2 indicates a 90% survival rate.
- With a score of 3, the survival rate is estimated at 77%.
- A score of 4 corresponds to a survival rate of 53%.
- A score of 5 suggests a survival rate of 21%.
- Scores of 6 or higher indicate a survival probability of less than 21%.

This scoring system helps healthcare providers assess long-term mortality risk in patients with multiple comorbidities based on their health conditions and age.

The Charlson Comorbidity Index (CCI) is a clinical calculator used to predict the ten-year mortality for a patient who may have a range of comorbid conditions. Each condition is assigned a score of 1, 2, 3, or 6, depending on the risk of dying associated with each one. Conditions include heart disease, AIDS, and cancer among others. The scores are summed to provide a total score to predict mortality. 

This calculator is applicable to a wide range of patients, particularly those with multiple comorbid conditions. It is often used in research settings to control for the confounding effect of comorbidities. 

The CCI is not recommended for use in patients without any comorbid conditions, as the score would be zero and not provide any additional prognostic information. It also may not be as accurate in populations with conditions not included in the original index, or in those with very high levels of comorbidity.