Relationship between Preoperative Hemoglobin and Hospital Stays in Patients Receiving Prime Total Knee Arthroplasty

Table 1

Demographics of patients with normal LOS (≤6 days) versus those with prolonged LOS (>6 days) after primary unilateral TKR.

Variable		LOS ≤ 6 N = 1879	LOS > 6 N = 394	value
Patient demographics
Age		65.9 ± 8.0	68.4 ± 8.2	<0.001
Race (n%)				0.023
	Chinese	1585 (84.4%)	329 (83.5%)
	Malay	143 (7.6%)	20 (5.1%)
	Indian	101 (5.4%)	29 (7.4%)
	Others	50(2.8%)	16 (4.1%)
Gender				0.310
	Female	1414 (75.3%)	306 (77.7%)
	Male	465 (24.7%)	88 (22.3%)
BMI				0.158
	≤25	543 (29.4%)	117 (31.0%)
	>25, ≤30	794 (42.9%)	163 (43.1%)
	>30, ≤35	393 (21.3%)	65 (17.2%)
	>35	119 (6.4%)	33 (8.7%)
Details of operation
Operation duration (min)		79.6 ± 21.6	83.7 ± 25.9	0.015
Type of anesthesia				0.102
	RA	1254 (66.7%)	242 (61.4%)
	GA	604 (32.1%)	146 (37.1%)
	GA RA	19 (1.0%)	5 (1.3%)
	GA LA	1 (0.1%)	0 (0.0%)
	GA other	1 (0.1%)	0 (0.0%)
	RA other	0 (0.0%)	1 (0.3%)
Day of week of op				<0.001
	Thursday	459 (24.4%)	54 (13.7%)
	Tuesday	408 (21.7%)	102 (25.9%)
	Wednesday	320 (17.0%)	74 (18.8%)
	Monday	302 (16.1%)	77 (19.5%)
	Friday	288 (15.3%)	72 (18.3%)
	Saturday	102 (5.4%)	15 (3.8%)
Patient comorbidities
Smoking				0.897
	No	1697 (90.3%)	355 (90.1%)
	Yes	182 (9.7%)	39 (9.9%)
DM				0.001
	No	1553 (82.7%)	298 (75.6%)
	Yes	326 (17.3%)	96 (24.4%)
DM on insulin
	No	1398 (74.4%)	300 (76.1%)	0.648
	Null	453 (24.1%)	87 (22.1%)
	Yes	28 (1.5%)	7 (1.8%)
IHD				0.025
	No	1792 (95.4%)	365 (92.6%)
	Yes	87 (4.6%)	29 (7.4%)
CCF				0.583
	No	1869 (99.5%)	391 (99.2%)
	Yes	10 (0.5%)	3 (0.8%)
CVA				<0.001
	No	1854 (98.7%)	375 (95.2%)
	Yes	25 (1.3%)	19 (4.8%)
Creatinine >2 mg/dL				0.352
	No	1671 (88.9%)	344 (87.3%)
	Null	199 (10.6%)	46 (11.7%)
	Yes	9 (0.5%)	4 (1.0%)
Repeat op within 30 days				<0.001
	No	1870 (99.7%)	387 (98.2%)
	Yes	5 (0.3%)	7 (1.8%)
HB categorical				<0.001
	<11	87 (4.6%)	40 (10.2%)
	≥11, <13	681 (36.2%)	163(41.4%)
	≥13	1111 (59.1%)	191 (48.5%)
ASA-PS				0.013
	1	136 (7.2%)	24 (6.1%)
	2	1650 (87.8%)	336 (85.3%)
	3	93 (4.9%)	34 (8.6%)

ASA-PS, American Society of Anesthesiologist Physical Status; CCF, congestive cardiac failure; CVA, cerebrovascular accidents; DM, diabetes mellitus; GA, general anesthesia; IHD, ischemic heart disease; LOS, length of stay; RA, regional anesthesia; TKR, total knee replacement. ASA-PS, American Society of Anesthesiologist Physical Status; CCF, congestive cardiac failure; CVA, cerebrovascular accidents; DM, diabetes mellitus; GA, general anesthesia; IHD, ischemic heart disease; LOS, length of stay; RA, regional anesthesia; REF, reference.