years
1 point each
2 points each
3 points
6 points each
How it's calculated
Each comorbidity present adds its weighted points (1, 2, 3, or 6, depending on associated prognostic impact), plus an age-adjustment of 1 point per decade of life over 40 (up to a maximum of 5 points at age 90+).
Interpretation
| Total score | Comorbidity burden |
|---|---|
| 0-1 | Low |
| 2-3 | Mild-to-moderate |
| 4-5 | High |
| ≥ 6 | Very high |
Clinical use
- Widely used in research to risk-adjust for comorbidity burden when comparing outcomes between patient groups.
- Used clinically to frame prognosis discussions and to weigh the risks and expected benefit of aggressive interventions (e.g. major surgery, dialysis, intensive cancer therapy) in patients with significant comorbidity.
- Higher scores are associated with progressively lower expected survival, though it should always be interpreted alongside the individual patient's functional status and specific clinical context.
Frequently asked questions
What does the Charlson Comorbidity Index measure?
The cumulative burden of a defined set of significant comorbid conditions, weighted by their association with mortality risk, plus an adjustment for age.
Is a higher or lower Charlson score worse?
Higher scores indicate greater comorbidity burden and are associated with higher mortality risk and lower expected survival.
Does the Charlson Index include every medical condition?
No — it uses a specific, validated list of comorbid condition categories. Conditions not on the list, however serious, are not scored, so it is a summary index rather than an exhaustive comorbidity count.
References
- Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies. J Chronic Dis. 1987;40(5):373-383.
- Quan H, et al. Updating and validating the Charlson Comorbidity Index. Am J Epidemiol. 2011.