Association of preoperative depression and cognitive status with postoperative delirium in elderly patients with hip fracture

Table 1 Baseline characteristics and comparison between patients with and without postoperative delirium, n (%)/mean ± SD/median (interquartile range)

Characteristic	Total (n = 150)	No POD (n = 104)	POD (n = 46)	P value
Demographics
Age (years)	78.4 ± 7.8	77.1 ± 7.7	81.2 ± 7.4	0.003
Age ≥ 80 years	61 (40.7)	36 (34.6)	25 (54.3)	0.024
Female sex	102 (68.0)	72 (69.2)	30 (65.2)	0.635
Body mass index (kg/m2)	22.8 ± 3.6	23.1 ± 3.5	22.1 ± 3.8	0.128
Education ≥ 6 years	89 (59.3)	64 (61.5)	25 (54.3)	0.413
Living alone	34 (22.7)	22 (21.2)	12 (26.1)	0.508
Current smoker	28 (18.7)	18 (17.3)	10 (21.7)	0.527
Fracture characteristics
Fracture type				0.624
Femoral neck	57 (38.0)	41 (39.4)	16 (34.8)
Intertrochanteric	86 (57.3)	58 (55.8)	28 (60.9)
Subtrochanteric	7 (4.7)	5 (4.8)	2 (4.3)
Fall as mechanism	134 (89.3)	92 (88.5)	42 (91.3)	0.604
Time to surgery (days)	3 (2, 5)	3 (2, 4)	3 (2, 5)	0.267
Comorbidities
Hypertension	98 (65.3)	66 (63.5)	32 (69.6)	0.477
Diabetes mellitus	42 (28.0)	27 (26.0)	15 (32.6)	0.409
Coronary artery disease	35 (23.3)	22 (21.2)	13 (28.3)	0.349
Chronic obstructive pulmonary disease	18 (12.0)	11 (10.6)	7 (15.2)	0.424
Cerebrovascular disease	22 (14.7)	13 (12.5)	9 (19.6)	0.263
Chronic kidney disease	15 (10.0)	8 (7.7)	7 (15.2)	0.154
Number of comorbidities ≥ 3	56 (37.3)	35 (33.7)	21 (45.7)	0.163
American Society of Anesthesiologists classification ≥ III	72 (48.0)	42 (40.4)	30 (65.2)	0.006
Preoperative assessments
GDS-15 score	4.2 ± 3.1	3.6 ± 2.8	5.6 ± 3.4	< 0.001
Depression (GDS-15 ≥ 5)	58 (38.7)	33 (31.7)	25 (54.3)	0.012
Mild depression (GDS-15: 5-8)	43 (28.7)	27 (26.0)	16 (34.8)
Moderate depression (GDS-15: 9-11)	12 (8.0)	5 (4.8)	7 (15.2)
Severe depression (GDS-15 ≥ 12)	3 (2.0)	1 (1.0)	2 (4.3)
MMSE score	24.8 ± 4.6	25.9 ± 3.8	22.4 ± 5.4	< 0.001
Cognitive impairment (MMSE < 24)	50 (33.3)	24 (23.1)	26 (56.5)	< 0.001
Activities of Daily Living score	82.4 ± 16.8	84.6 ± 15.2	77.2 ± 19.1	0.015
Preoperative laboratory values
Hemoglobin (g/L)	108.2 ± 17.6	110.5 ± 16.2	103.2 ± 18.6	0.021
< 100 g/L	38 (25.3)	21 (20.2)	17 (37.0)	0.032
Albumin (g/L)	36.0 ± 4.6	36.8 ± 4.2	34.2 ± 4.8	0.002
Albumin < 35 g/L	52 (34.7)	29 (27.9)	23 (50.0)	0.009
Creatinine (μmol/L)	78 (65, 95)	76 (64, 92)	82 (68, 98)	0.142
Surgical characteristics
Surgical procedure				0.482
Internal fixation	87 (58.0)	62 (59.6)	25 (54.3)
Hemiarthroplasty	46 (30.7)	30 (28.8)	16 (34.8)
Total hip arthroplasty	17 (11.3)	12 (11.5)	5 (10.9)
Anesthesia type				0.584
General	84 (56.0)	57 (54.8)	27 (58.7)
Regional	66 (44.0)	47 (45.2)	19 (41.3)
Surgical duration (minutes)	117.8 ± 35.2	112.3 ± 32.6	128.6 ± 38.4	0.008
> 120 minutes	58 (38.7)	34 (32.7)	24 (52.2)	0.026
Blood loss (mL)	300 (200, 450)	300 (200, 400)	350 (200, 500)	0.186
Intraoperative transfusion	51 (34.0)	30 (28.8)	21 (45.7)	0.048

GDS-15: 15-item Geriatric Depression Scale; MMSE: Mini-Mental State Examination; POD: Postoperative delirium.