Table 1.

Distribution of demographic and clinical characteristics of THR patients by ASA class preoperatively (n = 69,290)

Variable	ASA class										P-value	Cramer’s V / Kendall tau
	Total		Class I		Class II		Class III		Class IV
	%	n	%	n	%	n	%	n	%	n
Sex											0.352	0.053
Men	43.2	29,965	46.0	8191	41.2	17,074	47.0	4584	53.0	116
Women	56.8	39,325	54.0	9631	58.8	24,418	53.0	5173	47.0	103
Age (years) [mean (SD)]	68.2 (10.2)		62.7 (10.4)		69.4 (9.4)		72.9 (9.2)		73.5 (10.1)		< 0.001	–
Age group (years)											< 0.001	0.282d
< 50	4.7	3246	11.2	1995	2.6	1094	1.5	151	2.7	6
50–59	13.5	9351	23.9	4251	10.8	4485	6.1	600	6.8	15
60–69	34.4	23,822	38.6	6886	34.8	14,453	24.9	2433	22.8	50
70–79	34.5	23,906	22.4	3986	37.9	15,720	42.2	4122	35.6	78
80–95	12.9	8965	4.0	704	13.8	5740	25.1	2451	32.0	70
BMI categorya											< 0.001	0.155d
Underweight	0.7	485	0.6	108	0.7	280	0.9	91	2.7	6
Normal weight	31.0	21,498	39.6	7066	28.9	12,008	24.3	2371	24.2	53
Overweight	44.3	30,694	46.2	8230	45.2	18,761	37.1	3621	37.4	82
Obese class I	18.5	12,806	12.0	2144	20.0	8291	23.8	2323	21.9	48
Obese class II	4.6	3168	1.3	231	4.5	1859	10.8	1056	10.0	22
Obese class III	0.9	639	0.2	43	0.7	293	3.0	295	3.7	8
Diagnosis											0.001	0.037
Primary OAb	92.6	64,142	92.2	16,426	93.2	38,687	90.6	8838	87.2	191
Otherc	7.4	5148	7.8	1396	6.8	2805	9.4	919	12.8	28
Side of operation											0.001	0.016
Right	55.7	38,623	54.4	9692	56.2	23,330	56.2	5482	54.3	119
Left	44.3	30,667	45.6	8130	43.8	18,162	43.8	4275	45.7	100

^a BMI categories: Underweight: < 18.5; Normal: 18.5–24.9; Overweight: 25.0–29.9; Obese class I: 30.0–34.9; Obese class II: 35.0–39.9; Obese class III: ≥ 40

^b Osteoarthritis

^c Other – Other secondary osteoarthritis, femoral head necrosis, sequelae after childhood disease in the hip joint, inflammatory joint disease, other

^d Kendall tau coefficient