Red Blood Cell Transfusion and Postoperative Delirium in Hip Fracture Surgery Patients: A Retrospective Observational Cohort Study

Table 3

Characteristics of patients in IPTW cohort.

Variable	No RBC transfusion	RBC transfusion	Standardized mean difference
	N = 3,089	N = 626
Age (years)	79 ± 5	79 ± 11	<0.01
Sex (% male)	856 (27.7)	170 (27.1)	0.01
Weight (kg)	68 ± 11	68 ± 24	<0.01
Height (cm)	164 ± 8	163 ± 16	0.08
Hematocrit (%)	37 ± 2	37 ± 4	<0.01
Platelet count × 10^9/L	213 ± 54	211 ± 120	0.02
Creatinine (mg/dL)	1.0 ± 0.5	1.0 ± 1.1	<0.01
INR	0.8 ± 0.30	0.8 ± 0.6	<0.01
Independent functional status at baseline	2,619 (84.8)	531 (84.8)	<0.01
Diabetes mellitus	568 (18.4)	128 (20.5)	0.05
Hypertension requiring medication	2,036 (65.9)	416 (66.4)	0.01
Congestive heart failure	62 (2.0)	18 (2.8)	0.05
Tobacco use	327 (10.6)	62 (9.9)	0.02
COPD	327 (10.6)	71 (11.4)	0.03
Dialysis	40 (1.3)	9 (1.4)	<0.01
Dementia	602 (19.5)	128 (20.5)	0.03
Disseminated cancer	111 (3.6)	19 (3.1)	0.03
Wound infection	80 (2.6)	15 (2.4)	0.01
Steroid use	185 (6.0)	41 (6.6)	0.02
Bleeding disorder	374 (12.1)	83 (13.2)	0.03
Transfused in 72 hours before surgery	22 (0.7)	5 (0.8)	0.01
Emergency surgery	775 (25.1)	197 (31.4)	0.14
Mortality probability (%)	3.4 ± 3.4	3.7 ± 6.7	0.06
Morbidity probability (%)	8.4 ± 3.0	9.0 ± 6.9	0.11
ASA class
I or II	720 (23.3)	128 (20.5)	0.07
III	1,942 (62.9)	392 (62.6)	<0.01
IV or V	427 (13.8)	106 (16.9)	0.09
Anesthesia type
General	2,215 (71.7)	457 (73.0)	0.03
Spinal	627 (20.3)	121 (19.3)	0.03
MAC and local	225 (7.3)	43 (6.9)	0.02
Regional	22 (0.7)	5 (0.8)	0.01
CPT code
27236	1,751 (56.7)	348 (55.6)	0.02
27244	229 (7.4)	41 (6.5)	0.04
27245	1,109 (35.9)	237 (37.8)	0.04
Duration of surgery (minutes)	89 ± 20	91 ± 45	0.06

ASA = American Society of Anesthesiologists, COPD = chronic obstructive pulmonary disease, CPT = current procedural terminology, INR = international normalized ratio, IPTW = inverse probability of treatment weighting, MAC = monitored anesthesia care, and RBC = red blood cell. CPT codes: 27236 (open treatment of femoral fracture, proximal end, neck, internal fixation, or prosthetic replacement), 27244 (treatment of intertrochanteric, peritrochanteric, or subtrochanteric femoral fracture with plate/screw-type implant), and 27245 (treatment of intertrochanteric, peritrochanteric, or subtrochanteric femoral fracture with intramedullary implant). Values are mean +sd or n (%) Timing of RBC transfusion: postoperative day (POD), POD0 = 121, POD1 = 178, POD2 = 234, POD3 = 90, and others = 3 Variable was included in the propensity score model. Other variables were not included in the propensity score model, but their balance was assessed.