BackgroundThe COVID-19 pandemic caused a surge of same-day discharge (SDD) for total joint arthroplasty. However, SDD may not be beneficial for all patients. Therefore, continued investigation into the safety of SDD is necessary as well as risk stratification for improved patient outcomes. MethodsThis retrospective cohort study examined 31,851 elective SDD hip and knee arthroplasties from 2016 to 2020 in a large national database. Logistic regression models were used to identify patient variables and preoperative comorbidities that contribute to postoperative complication or readmission with SDD. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were calculated. ResultsSDD increased from 1.4% in 2016 to 14.6% in 2020. SDD is associated with lower odds of readmission (AOR: 0.994, CI: 0.992-0.996) and postoperative complications (AOR: 0.998, CI: 0.997-1.000). Patients who have preoperative dyspnea (AOR: 1.03, CI: 1.02-1.04, P < .001), chronic obstructive pulmonary disease (AOR: 1.02, CI: 1.01-1.03, P = .002), and hypoalbuminemia (AOR: 1.02, CI: 1.00-1.03, P < .001), had higher odds of postoperative complications. Patients who had preoperative dyspnea (AOR: 1.02, CI: 1.01-1.03), hypertension (AOR: 1.01, CI: 1.01-1.03, P = .003), chronic corticosteroid use (AOR: 1.02, CI: 1.01-1.03, P < .001), bleeding disorder (AOR: 1.02; CI: 1.01-1.03, P < .001), and hypoalbuminemia (AOR: 1.01, CI: 1.00-1.02, P = .038), had higher odds of readmission. ConclusionSDD is safe with certain comorbidities. Preoperative screening for cardiopulmonary comorbidities (eg, dyspnea, hypertension, and chronic obstructive pulmonary disease), chronic corticosteroid use, bleeding disorder, and hypoalbuminemia may improve SDD outcomes.