Study Cohort
ICD-10-CM/PCS codes were used to search discharges in the 2016 NRD who
had a principle diagnosis of AMI (including ST and non-ST elevation
AMIs) and a principle procedure of either PR or SR during the index
hospitalization; baseline characteristics, comorbidities, in-hospital
procedural complications, and endpoints of interest were subsequently
extracted. To differentiate post-procedural complications from chronic
conditions, the 2016 NRD has a present-on-admission indicator for
chronic conditions that present on admission. We also utilized the
ICD-10-CM codes used in the Elixhauser comorbidity index to identify
comorbid conditions and utilized ICD-10-CM codes that are specific for
post-procedural complications, Supplemental Table
1.[17] We excluded patients that did not have AMI
as a principle diagnosis and AMIs that were not treated invasively (i.e.
PR or SR) or when the revascularization was not the principle procedure.
We also excluded AMIs that were treated with a combination of both PR
and SR during the same indexed admission. The NRD excludes discharges
with missing age, missing or questionable linkage numbers or from
hospitals with more than 50% of their discharges excluded because of
these criteria, as patients treated in these hospitals may not be
reliably tracked over time.[16] All HCUP
recommendations and best practices to use the HCUP datasets highlighted
by Khera et al were followed.[18]