Study design:
This is a retrospective cohort study from the Nationwide Readmission
Database (NRD), a part of the Healthcare Cost and Utilization Project
(HCUP) maintained by the Agency for Healthcare Research and Quality. NRD
contains de-identified patient level public discharge data from 22
states, with an average of 14 million discharges per year, accounting
for 56.6% of US hospitalizations. The NRD data elements include
hospital characteristics, patient demographics, chronic co-morbidities,
procedures, primary and secondary discharge diagnoses, payment source,
and total costs. Since the database contains de-identified data, this
study was exempted from institutional review board approval.