Development of frailty index using ICD-10 codes to predict mortality and rehospitalization of older adults: An update of the multimorbidity frailty index

This study aims to develop an updated mFI (multimorbidity frailty index) using ICD-10-CM codes and to examine the association between frailty and all-cause mortality, unplanned hospitalization, and ICU admission by adopting the updated mFI in the contemporary ICD-10-CM era.