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

Table 1 Comparison of clinical characteristics before matching between the two groups, n (%)

	Winter (n = 63)	Summer (n = 62)	Z/t/χ2	P value
Age (years, P25-P75)	70 (67-78)	70 (66.75-73.25)	-1.230	0.219
Gender
Male	34 (54)	38 (61.3)	0.686	0.408
Female	29 (46)	24 (38.7)
BMI (kg/cm2, mean ± SD)	24.05 ± 3.39	22.44 ± 3.04	2.792	0.006
Education level
> Junior high	24 (38.1)	21 (33.9)	0.242	0.623
≤ Junior high	39 (61.9)	41 (66.1)
Surgical duration
≥ 3 hours	32 (50.8)	37 (59.7)	0.997	0.318
< 3 hours	31 (49.2)	25 (40.3)
Hypertension	35 (55.6)	30 (48.4)	0.643	0.423
Diabetes	10 (15.9)	7 (11.3)	0.558	0.455
Cardiovascular disorders	8 (12.7)	5 (8.1)	0.720	0.396
Cerebrovascular disorders	5 (7.9)	7 (11.3)
Anemia	4 (6.3)	8 (12.9)	1.547	0.214
Hypoalbuminemia	7 (11.1)	16 (25.8)	4.494	0.034
Elevated creatinine	7 (11.1)	6 (9.7)	0.069	0.793
Surgical grading			2.399	0.49
I	32 (50.8)	35 (56.5)
II	15 (23.8)	18 (29)
III	10 (15.9)	6 (9.7)
IV	6 (9.5)	3 (4.8)
PPS on postoperative day 1			0.748	0.688
< 4	25	20
4-6	28	31
> 6	10	11
PPS on postoperative day 3			0.778	0.678
< 4	39	43
4-6	18	14
> 6	6	5
PPS on postoperative day 7			-	0.440
< 4	58	60
4-6	5	2
> 6	0	0

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