Development and evaluation of a list of high-risk inpatient procedures in patients 65 years and older

Background: Inpatient procedures are common and important health events for older Americans. To facilitate surgical outcomes research, we sought to create and evaluate lists of International Classification of Disease, Tenth Revision (ICD-10) codes for high-risk inpatient procedures, defined as having at least a 1% inpatient mortality.

Methods: This retrospective national cohort study analyzes Medicare claims from 2018 for patients 65 years and older undergoing inpatient procedures. Surgical Diagnosis Related Group (DRG) codes in the inpatient claims were used to identify procedures. We identified the primary ICD-10 procedure code for each patient and then compiled all codes with at least a 1% inpatient mortality yielding three separate lists: one list that was blind to elective versus urgent/emergent status, and one each for urgent/emergent and elective procedures. Clinical review by three surgeons was used to remove procedures unlikely to be the proximate cause of mortality. For evaluation, we examined the mortality of each code among fee-for-service Medicare beneficiaries in 2017, 2019, and 2020 to determine how many of these satisfied the 1% mortality criterion.

Results: This study included 2,241,419 patients from 2018 undergoing inpatient procedures. The final result included 231 (blind to elective vs urgent/emergent status), 167 (urgent/emergent status), and 119 (elective status) ICD-10 procedure codes for the three lists. Our evaluation from 2017, 2019, and 2020 demonstrated that in our master list, which was blind to elective versus urgent/emergent status, 97.8% of procedures had an inpatient mortality of at least 1%. In our high-risk procedures lists for urgent/emergent and elective procedures, 100% and 94.1% of codes met this requirement.

Conclusions: We developed and evaluated lists of ICD-10 codes representing high-risk procedures in patients 65 years and older. These lists will be powerful tools for researchers studying surgical outcomes.