Table 1.

Baseline characteristics of the patients.

Variable	POD	Non-POD	P value
Age (years)	79.00 ± 2.51	72.05 ± 2.94	<0.01
Sex (female/male)	9/20	28/47	0.55
Living alone (Y/N)	17/12	38/37	0.47
Type of surgery(gastrectomy/enterectomy)	6/23	16/59	0.83
ASA scale (II/III)	17/12	59/16	0.04
Serum albumin levels (g/L)	44.10 ± 3.56	45.38 ± 2.34	0.02
Preoperative MMSE score	26 (25, 27)	27 (26, 27)	0.62
Duration of anesthesia (minutes)	165.97 ± 10.36	147.89 ± 9.06	<0.01
Blood loss (mL)	336.59 ± 22.74	328.36 ± 23.18	0.11
Transfusion (Y/N)	6/23	8/67	0.18
Requirement of postoperative analgesia (Y/N)	10/19	21/54	0.52
Serum melatonin levels
Preoperative (ng/L)	68.35 ± 7.94	66.72 ± 8.21	0.36
Postoperative (ng/L)	43.61 ± 3.60	52.34 ± 5.73	<0.01
Change in melatonin	26.50 ± 8.35	14.38 ± 10.67	<0.01

Abbreviations: ASA, American Society of Anesthesiologists; MMSE, Mini-Mental State Examination; POD, postoperative delirium; Y: yes; N: no.