Quan et al. developed ICD-10 codes and enhanced ICD-9-CM codes for the sixteen Charlson comorbidities using Deyo's ICD-9-CM coding. They also developed the ICD-10 and enhanced ICD-9-CM codes for the thirty Elixhauser comorbidities using the original ICD-9-CM and the AHRQ-Web ICD-9-CM. The following slides focus on the development of the ICD-10 codes for both comorbidities.