Key points are not available for this paper at this time.
Many versions of the Charlson Comorbidity Index are used in parallel, so clear reporting of the version, exact ICD- coding and weighting is necessary to obtain transparency and reproducibility in research. Yet, the version of the Royal College of Surgeons is up-to-date and easy-to-use, and therefore an acceptable co-morbidity score to be used in registry-based research especially for surgical patients.
Lagergren et al. (Sun,) studied this question.