Table 1. Characteristics of hip fracture patients with and without postoperative delirium.

Characteristics are shown as number of patients (%) unless stated otherwise.

	Postoperative delirium	No postoperative delirium	p-value
	N = 12	N = 47
Mean age in years (SD)	86.4 (8.0)	83.4 (7.7)	0.24
Sex male	2 (16.7)	16 (34.0)	0.31
Living at home	8 (66.7)	35 (74.5)	0.69
Social status			0.30
Living alone	9 (75.0)	22 (46.8)
Living together with partner/child	2 (16.7)	13 (27.7)
missing	1 (8.3)	12 (25.5)
Median preadmission KATZ-ADL-6 score (q1-q3)	4 (0–5)	1.5 (0–4)	0.30
missing	0 (0.0)	7 (14.9)
Median Charlson Comorbidity Index (q1—q3)	2 (1–3)	2 (1–4)	0.97
Premorbid cognitive impairment	3 (25.0)	11 (23.4)	1.00
Type of fracture			0.62
intertrochanteric	6 (50.0)	27 (57.4)
femoral neck	6 (50.0)	16 (34.0)
other	0 (0.0)	4 (8.5)
Type of surgery			0.44
internal fixation	8 (66.7)	38 (80.9)
hip replacement	4 (33.3)	9 (19.1)
Median time to surgery in days (q1-q3)	1 (0.3–1)	1 (0–1)	0.61
Time of obtaining CSF			0.82
24:00–06:00	0 (0.0)	0 (0.0)
06:00–12:00	2 (16.7)	10 (21.3)
12:00–18:00	7 (58.3)	27 (57.4)
18:00–24:00	3 (25.0)	8 (17.0)
missing	0 (0.0)	2 (4.3)
Season of obtaining CSF			0.56
spring	4 (33.3)	13 (27.7)
summer	2 (16.7)	14 (29.8)
autumn	5 (41.7)	12 (25.5)
winter	1 (8.3)	8 (17.0)
Overall mean CSF melatonin level in pg/ml (SD)	12.88 (6.3)	11.72 (4.5)	0.47
Mean CSF melatonin level stratified for time of the day of sampling in pg/ml (SD)
06:00–12:00	9.30 (1.0)	9.05 (4.1)	0.94
12:00–18:00	11.71 (3.5)	12.97 (4.0)	0.45
18:00–24:00	18.00 (11.1)	10.13 (5.1)	0.13

q1-q3 = first quartile—third quartile, CSF = Cerebrospinal Fluid, SD = Standard Deviation, ADL = Activities of Daily Living