Table 3. Patients missing preoperative delirium assessments.

	No preoperative delirium assessment	All others	p-valuea
	N = 160	N = 536
BMI, median (IQR)	22 (19–24)	23 (21–26)	0.01
Time admission to surgery, hours, median (IQR)	10 (5–20)	24 (16–41)	<0.001
Surgery started between 5:00 p.m. and 6:30 a.m., n/N (%)	90/160 (56)	219/528 (42)	0.001

BMI = Body Mass Index; IQR = Interquartile range. Missing data: BMI: N = 134, Time of surgery, N = 8

^a Mann-Whitney tests for skewed continuous variables, chi-square tests for categorical variables, p-values are 2-tailed.