Impact of ambient temperature on postoperative cognitive dysfunction in elderly patients surgery: A seasonal comparison in tropical regions

Table 2 Comparison of clinical characteristics after matching between the two groups, n (%)

	Winter (n = 41)	Summer (n = 41)	Z/t/χ2	P value
Age (years, P25-P75)	69 (67-75)	71 (68-75.5)	-1.214	0.225
Gender
Male	24 (58.5)	24 (58.5)	< 0.001	1
Female	17 (41.5)	17 (41.5)
BMI (kg/cm2, mean ± SD)	23.17 ± 3.01	23.12 ± 3.13	0.077	0.939
Education level
> Junior high	14 (34.1)	14 (34.1)	< 0.001	1
≤ Junior high	27 (65.9)	27 (65.9)
Surgical duration
≥ 3 hours	19 (46.3)	22 (53.7)	0.439	0.508
< 3 hours	22 (53.7)	19 (46.3)
Hypertension	21 (51.2)	22 (53.7)	0.049	0.825
Diabetes	6 (14.6)	5 (12.2)	0.105	0.746
Cardiovascular disorders	2 (4.9)	4 (9.8)	-	0.675
Cerebrovascular disorders	4 (9.8)	6 (14.6)	0.456	0.500
Anemia	3 (7.3)	3 (7.3)	-	1
Hypoalbuminemia	7 (17.1)	8 (19.5)	0.082	0.775
Elevated creatinine	4 (9.8)	5 (12.2)	-	1
Surgical grading			0.847	0.838
I	21 (51.2)	25 (61.0)
II	10 (24.4)	8 (19.5)
III	7 (17.1)	6 (14.6)
IV	3 (7.3)	2 (4.9)
PPS on postoperative day 1			-	0.782
< 4	20	17
4-6	18	20
> 6	3	4
PPS on Postoperative day 3			-	0.546
< 4	30	33
4-6	10	6
> 6	1	2
PPS on postoperative day 7			-	1
< 4	39	39
4-6	2	2
> 6	0	0

BMI: Body mass index; PPS: Postoperative pain scores.