Outcomes of early hospital readmission after kidney transplantation: Perspectives from a Canadian transplant centre

Table 1 Baseline recipient, donor, and transplant characteristics by early hospital readmission status

Variables	EHR within 30 d after transplant discharge				EHR within 90 d after transplant discharge
	Number of patients, n = 1368	Yes, n = 307	No, n = 1061	P value	Number of patients, n = 1333	Yes, n = 394	No, n = 939	P value
Recipient characteristics
Recipient age at transplant in yr, mean (± SD)	1368	52.4 (13.4)	51.4 (13.6)	0.26	1333	52.7 (13.4)	51.1 (13.6)	0.05
Recipient sex
Male	821	185 (60.3%)	636 (59.9%)	0.92	802	235 (59.6%)	567 (60.4%)	0.80
Female	547	122 (39.7%)	425 (40.1%)		531	159 (40.4%)	372 (39.6%)
Recipient race
White	639	134 (56.3%)	505 (59.1%)	0.44	632	176 (57.1%)	456 (59.1%)	0.56
Non-white	454	104 (43.7%)	350 (40.9%)		448	132 (42.9%)	316 (40.9%)
History of smoking
Smoker	584	137 (44.8%)	447 (42.3%)	0.42	569	174 (44.5%)	395 (42.1%)	0.42
Non-smoker	780	169 (55.2%)	611 (57.8%)		760	217 (55.5%)	543 (57.9%)
History of diabetes mellitus	467	111 (36.2%)	356 (33.6%)	0.40	455	151 (38.3%)	304 (32.4%)	0.04
History of chronic lung disease	57	14 (4.6%)	43 (4.1%)	0.70	56	21 (5.3%)	35 (3.7%)	0.19
History of cardiovascular disease	377	82 (26.7%)	295 (27.8%)	0.70	368	118 (30.0%)	250 (26.7%)	0.22
Recipient body mass index at transplant discharge in kg/m2, mean (± SD)	1074	27.2 (6.0)	26.9 (5.9)	0.49	1333	52.7 (13.4)	51.1 (13.6)	0.05
Recipient eGFR at baseline in mL/min, mean (± SD)	1085	62.7 (26.5)	63.0 (28.0)	0.88	1072	60.7 (27.0)	64.0 (27.7)	0.08
Time on dialysis in yr, mean (± IQR)	1368	3.4 (1.2, 5.6)	3.2 (1.2, 5.3)	0.46	1333	3.5 (1.6, 5.8)	3.1 (1.1, 5.3)	0.02
Donor characteristics
Donor age at donation in yr, mean (± SD)	1359	48.9 (14.2)	47.3 (15.0)	0.10	1325	49.3 (14.4)	47.0 (14.9)	0.01
Donor body mass index in kg/m2, (mean ± SD)	1339	26.9 (5.6)	26.7 (5.4)	0.56	1305	26.7 (5.4)	26.8 (5.4)	0.70
Type of donation
Deceased	766	178 (58.0%)	588 (55.4%)	0.43	742	234 (59.4%)	508 (54.1%)	0.08
Living	602	129 (42.0%)	473 (44.6%)		591	160 (40.6%)	431 (45.9%)
Expanded criteria donor	256	70 (22.8%)	186 (17.5%)	0.04	249	94 (23.9%)	155 (16.5%)	0.002
Transplant characteristics
Peak PRA
0%	709	161 (52.6%)	548 (51.7%)	0.78	686	211 (53.7%)	475 (50.6%)	0.31
> 0%	657	145 (47.4%)	512 (48.3%)		645	182 (46.3%)	463 (49.4%)
Delayed graft function	276	57 (18.6%)	219 (20.6%)	0.43	265	79 (20.1%)	186 (19.8%)	0.92
Biopsy-proven acute rejection	85	46 (15.0%)	39 (3.7%)	< 0.001	98	59 (15.0%)	39 (4.2%)	< 0.001
Transplant era
2009-2011	429	94 (30.6%)	335 (31.6%)	0.002	429	131 (33.3%)	298 (31.7%)	< 0.001
2012-2014	431	75 (24.4%)	356 (33.6%)		430	96 (24.4%)	334 (35.6%)
2015-2017	508	138 (45.0%)	370 (34.9%)		474	167 (42.4%)	307 (32.7%)

Mean and median values were reported with standard deviation and interquartile range, respectively. IQR: Interquartile range; eGFR: Estimated glomerular filtration rate; EHR: Early hospital readmissions; PRA: Panel reactive antibody; SD: Standard deviation.

Table 2 Association of early hospital readmission with graft failure or death, graft failure, death, and late hospital admissions (within 1 yr after the first 30 d or 90 d post-transplant discharge)

Outcome	30-d EHR			90-d EHR
	Number of outcomes	Full model1		Number of outcomes	Full model1
		HR (95%CI)	P value		HR (95%CI)	P value
Graft failure or death	237	1.06 (0.77-1.45)	0.73	232	1.21 (0.91-1.61)	0.19
Graft failure	92	1.05 (0.62-1.77)	0.86	92	1.45 (0.92-2.29)	0.11
Death	145	1.08 (0.73-1.60)	0.71	140	1.09 (0.75-1.57)	0.66
LHR	439	1.73 (1.40-2.13)	< 0.001	368	1.58 (1.27-1.97)	< 0.001

¹This Cox proportional hazard model for the association of 30-d early hospital readmissions on outcomes included early hospital readmission status, recipient characteristics (age, sex, race, body mass index at transplant discharge, history of smoking, diabetes, chronic lung disease and cardiovascular disease, estimated glomerular filtration rate at baseline, and time on dialysis), donor characteristics (age, body mass index at time of donation, donation type, and expanded-criteria status), and transplant characteristics (peak panel reactive antibodies, delayed graft function, acute rejection within 30 d of discharge, and transplant era). CI: Confidence interval; EHRs: Early hospital readmissions; HR: Hazard ratio; LHRs: Late hospital readmissions.

Table 3 Association of early hospital readmission with estimated glomerular filtration rate at 6-mo and 12-mo after transplant discharge

Outcomes	30-d HER, Full model1		90-d HER, Full model1
	Coefficient (95%CI)	P value	Coefficient (95%CI)	P value
eGFR at 6 mo after transplant discharge	-1.38 (-3.87 to 1.12)	0.28	-2.18 (-4.40 to -0.03)	0.054
eGFR at 12 mo after transplant discharge	-3.11 (-5.62 to -0.60)	0.02	-3.77 (-6.15 to -1.38)	0.002

¹The linear regression model for the association of 30-d early hospital readmissions on estimated glomerular filtration rate included early hospital readmissions status, recipient characteristics (age, sex, race, body mass index at transplant discharge, history of smoking, diabetes, chronic lung disease and cardiovascular disease, estimated glomerular filtration rate at baseline, and time on dialysis), donor characteristics (age, body mass index at time of donation, donation type, and expanded-criteria status), and transplant characteristics (peak panel reactive antibody, delayed graft function, acute rejection within 30 d of discharge, and transplant era). CI: Confidence interval; eGFR: Estimated glomerular filtration rate; EHR: Early hospital readmissions.