Charlson Comorbidity Index

Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. Derived the weighted 17-category comorbidity index and the approximate 1-year mortality by score band used here (0: ~12%, 1–2: ~26%, 3–4: ~52%, ≥ 5: ~85%) from a cohort of 559 medical inpatients, validated in a second cohort of 685 patients.

The age-adjusted variant shown alongside the score (+1 point per decade of life from age 50, up to +5 at ≥ 90) is the form most commonly used in later research and clinical risk models; only the unadjusted score is mapped to the mortality figures above, which come from the 1987 derivation cohort — later populations and treatments have generally had better outcomes at a given score, and ICD-coded (Deyo/Quan) versions of the index can classify a small number of conditions differently from the original chart-review definitions.