Factors Predicting Overnight Admission after Same-Day Mastectomy Protocol and Associated Financial Implications.

BACKGROUND:Same-day mastectomy (SDM) protocols have been shown to be safe, and their use increased up to four-fold compared to pre-pandemic rates. We sought to identify factors that predict overnight patient admission and evaluate the associated cost of care. STUDY DESIGN:Patients undergoing mastectomy from March 2020 to April 2022 were analyzed. Patients' demographics, tumor characteristics, operative details, perioperative factors, 30-day complications, fixed and variable cost, and contribution margin (CM) were compared between those who underwent SDM vs. those who required overnight admission after mastectomy (OAM). RESULTS:Of a total of 183 patients with planned SDM, 104 (57%) had SDM and 79 (43%) had OAM. Both groups had similar demographic, tumor, and operative characteristics. OAM patients were more likely to be preoperative opioid users (POU) (p=0.002), have higher American Society of Anesthesiology (ASA) class (p= 0.028), and more likely to have procedure start time (PST) after 12:00 PM (49% vs. 33%, p=0.033). The rates of 30-day unplanned postoperative events were similar between SDM and OAM. POU (OR 3.62 CI 1.56 - 8.40), PACU length of stay greater than one hour (OR 1.17 CI 1.01 - 1.37), and PST after 12:00 PM (OR 2.56 CI 1.19 - 5.51), were independent predictors of OAM on multivariate analysis. Both fixed ($ 5,545 vs $4,909, p=0.03) and variable costs ($6,426 vs $4,909, p=0.03) were higher for OAM compared to SDM. CM, was not significantly different between the two groups (-$431 SDM vs -$734 OAM, p=0.46). CONCLUSIONS:Preoperative opioid use, ASA class, longer PACU length of stay, and PST after noon predict a higher likelihood of admission following planned SDM. OAM translated to higher costs, but not to decreased profit for the hospital.