Table 1.

Comparison of baseline information between the two groups (n (%), (false ± s)$\overline{x}$).

Groups		Observation groups (n = 53)	Control groups (n = 53)	t/χ 2	P
Sex (cases)	Male	29 (54.72)	31 (58.49)	0.154	0.695
	Female	24 (45.28)	22 (41.51)
Age (y)		52.36 ± 6.45	51.32 ± 5.43	0.898	0.371
BMI (kg/m2)		23.88 ± 2.12	24.11 ± 2.52	0.508	0.612
ASA	Level I	23 (43.40)	25 (47.17)	0.152	0.696
	Level II	11 (20.75)	13 (24.53)	0.215	0.643
	Level III	19 (35.85)	15 (28.30)	0.693	0.405