Table 2.

Baseline characteristics before and after PSM

Characteristics	Before PSM				After PSM
	Hypokalemia (390)	Normal (5793)	P value	SMD (%)	Hypokalemia (390)	Normal (390)	P value	SMD (%)
K+	3.2 ± 0.2	4.1 ± 0.4	< 0.01*	—	3.2 ± 0.2	4.1 ± 0.4	< 0.01*	—
Age (year)	66.9 ± 12.0	63.0 ± 12.2	< 0.01*	30.4	66.9 ± 12.0	66.7 ± 10.7	0.756	2.2
Sex			< 0.01*	32.7			0.217	8.8
Male	172 (44.1%)	3426 (59.1%)			172 (44.1%)	155 (39.7%)
Female	218 (55.9%)	2367 (40.9%)			218 (55.9%)	235 (60.3%)
BMI (kg/m2)	22.5 ± 3.3	22.6 ± 3.2	0.538	3.2	22.5 ± 3.3	22.6 ± 3.3	0.649	3.3
Smoking	107 (27.4%)	2184 (37.7%)	< 0.01*	22.0	107 (27.4%)	98 (25.1%)	0.464	5.2
Drinking	79 (20.3%)	1797 (31.0%)	< 0.01*	24.8	79 (20.3%)	74 (19.0%)	0.652	3.2
Hypertension	167 (42.8%)	1419 (24.5%)	< 0.01*	39.5	167 (42.8%)	157 (40.3%)	0.467	5.2
T2DM	67 (17.2%)	612 (10.6%)	< 0.01*	19.2	67 (17.2%)	59 (15.1%)	0.436	5.6
CHD	30 (7.7%)	256 (4.4%)	0.003*	13.7	30 (7.7%)	25 (6.4%)	0.484	5.0
Surgical history	95 (24.4%)	1404 (24.2%)	0.956	0.3	95 (24.4%)	102 (26.2%)	0.564	4.1
Laparoscopy	310 (79.5%)	5052 (87.2%)	< 0.01*	20.8	310 (79.5%)	317 (81.3%)	0.528	4.5
Tumor size			0.047*	10.3			0.943	0.5
< 5 cm	216 (55.4%)	3503 (60.5%)			216 (55.4%)	215 (55.1%)
≥ 5 cm	174 (44.6%)	2290 (39.5%)			174 (44.6%)	175 (50.2%)
Tumor location			0.001*	17.0			0.613	3.6
Colon	219 (56.2%)	2763 (47.7%)			219 (56.2%)	226 (57.9%)
Rectum	171 (43.8%)	3030 (52.3%)			171 (43.8%)	164 (42.1%)
Tumor stage			0.197	8.3			0.583	2.2
I	62 (15.9%)	1135 (19.6%)			62 (15.9%)	62 (15.9%)
II	169 (43.3%)	2429 (41.9%)			169 (43.3%)	163 (41.8%)
III	159 (40.8%)	2229 (38.5%)			159 (40.8%)	165 (42.3%)

Note: Variables are expressed as the mean ± SD, n (%), *P-value < 0.05

Abbreviations: PSM Propensity score matching, SMD standardized mean difference, T2DM Type 2 diabetes mellitus, BMI Body mass index, CHD Coronary heart disease