primary care & preventionscoring tool

Charlson Comorbidity Index (CCI)

The Charlson Comorbidity Index quantifies the burden of comorbid diseases to predict 10-year mortality risk. It assigns weighted scores (1–6) to 19 conditions based on their impact on mortality. The CCI is the most widely used comorbidity index in clinical research.

inputs

✓ when to use

Use for risk adjustment in research, quality improvement, and outcome comparison across patient populations. In clinical practice, useful for prognostic discussions, treatment intensity decisions, and communicating overall disease burden. Some versions include an age adjustment (1 point per decade above 40).

✗ when not to use

The CCI predicts mortality, not functional status or quality of life. It was derived in 1987 — some conditions (e.g., AIDS) carry different prognostic weight in the era of modern treatment. The index does not capture condition severity (e.g., well-controlled vs decompensated heart failure both score 1). For risk adjustment in surgical outcomes, consider procedure-specific tools.

clinical pearls

  • Metastatic cancer (6 points) and AIDS (6 points) are the highest-weighted conditions, reflecting their dominant mortality impact at the time of derivation. In 2026, these weightings may overestimate risk given advances in cancer immunotherapy and HIV/AIDS treatment.
  • Some conditions are mutually exclusive or hierarchical: score mild liver disease (1) OR moderate-severe (3), not both. Similarly, uncomplicated diabetes (1) OR complicated diabetes (2), not both.
  • The age-adjusted CCI adds 1 point per decade of age above 40 (e.g., age 50 = +1, age 60 = +2). This version is commonly used in research but less commonly in clinical practice.
  • A CCI of 0 does not mean the patient is healthy — it means they do not have any of the 19 indexed conditions. They may still have other significant health issues not captured by the index.
  • In clinical practice, the CCI is most useful for framing conversations about treatment intensity. A patient with CCI 7 being considered for aggressive surgery deserves an explicit discussion about whether the intervention is likely to provide meaningful benefit given their overall prognosis.

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