Table 2.

Single-factor chi-square analysis of preoperative variables (N = 167)

Factors	Classification	Number	Percent	Mean ± SD	F value	P value
Pre-operation Hb (g/L)	Hb < 100	5	3.00	20.00 ± 5.79	5.457	0.104
	100 ≤ Hb < 110	13	7.80	22.08 ± 10.17
	110 ≤ Hb < 120	23	13.80	21.74 ± 7.09
	120 ≤ Hb < 130	52	31.10	17.29 ± 4.68
	130 ≤ Hb < 140	46	27.50	18.87 ± 7.60
	140 ≤ Hb	28	16.80	19.21 ± 4.98
Pre-operation albumin (g/L)	< 30	2	1.20	33.50 ± 4.95	4.675	0.002
	≥ 30	165	98.80	18.94 ± 6.48
Pre-operation ESR (mm/h)	< 15	77	46.10	17.71 ± 5.22	6.560	0.011
	≥ 15	90	53.90	20.31 ± 7.47
Pre-operation CRP (mg/L)	< 5	44	26.30	18.55 ± 6.48	0.371	0.691
	≥ 5	122	73.70	19.29 ± 6.73
Primary disease	RA	16	9.60	23.50 ± 7.80	8.050	0.005
	OA	151	90.40	18.65 ± 6.36
Merge disease	No	112	67.10	18.36 ± 5.96	4.509	0.035
	Yes	55	32.90	20.65 ± 7.68
ASA class	1	38	22.80	16.61 ± 5.17	3.844	0.023
	2	120	71.90	19.75 ± 6.53
	3	9	5.40	21.22 ± 10.76

Hb hemoglobin, ESR erythrocyte sedimentation, CRP C-reactive protein, ASA American Society of Anesthesiologists