Table 2.

Differences in postoperative length of stay, anesthesia conversion, and postoperative adverse events between patients with and without preoperative anxiety

Adverse events	No preoperative anxiety	Preoperative anxiety	Adjusted difference (95% CI)	P	Test statistic
Postoperative LOS (n=8373)	2.9 h (1.3)	3.0 h (1.3)	2.9 min (−0.84 min-6.7 min)	0.13	1.52
Conversion from MAC to general anesthesia (n=4786), n (%)	505 (13.0)	83 (11.0)	−1.8% (−4.0%-0.44%)	0.13	−1.50
Any use of postoperative PONV medication (n=8665), n (%)	715 (9.9)	181 (12.5)	1.8% (0.12%-3.4%)	0.029	2.19
Same day resurgery (n=8665), n (%)	27 (0.4)	12 (0.8)	0.45% (−0.034%-0.94%)	0.022	2.29
Transfer from Outpatient Surgery Center (n=8665), n (%)	17 (0.2)	4 (0.3)	0.048% (−0.25%-0.34%)	0.7	0.33
Overnight stay (n=8626), n (%)	184 (2.6)	54 (3.8)	1.1% (0.07%-2.0%)	0.021	2.32
Grade 3 or higher complication within 30 days (n=8665), n (%)	11 (0.2)	8 (0.6)	0.40% (0.007%-0.79%)	0.006	2.77
UCC visit within 30 days (n=8665), n (%)	183 (2.5)	58 (4.0)	1.5% (0.44%-2.6%)	0.002	3.16
Readmission within 30 days (n=8665), n (%)	104 (1.4)	34 (2.4)	0.97% (0.13%-1.8%)	0.008	2.65

Postoperative LOS in each group reported in h as mean (SD) with adjusted difference in postoperative LOS between groups in minutes with 95% CI; test statistic reported is t statistic from multivariable linear regression model. Anesthesia conversion and postoperative adverse event rates reported as frequency (%) in each group and adjusted difference in rates between groups reported with 95% CI; test statistic reported is Z statistic from multivariable logistic regression model. The adjusted difference is positive, if LOS, anesthesia conversion, or adverse event rates were higher in patients with preoperative anxiety, and negative, if lower in patients with preoperative anxiety. SD: Standard deviation, CI: Confidence interval, LOS: Length of stay, MAC: Monitored anesthesia care, PONV: Postoperative nausea and vomiting, UCC: Urgent care center