Incidence, risk factors, and outcome of BK polyomavirus infection after kidney transplantation

Table 3 Characteristics of kidney recipients with BK-viremia and negative (No polyomavirus-associated nephropathy group) or positive allograft histology (Polyomavirus-associated nephropathy group)

Variables	Median (IQR) or n (%)		P
	No PVAN group	PVAN group
Patients	20	40
Recipient Male : Female	13 : 7	26 : 14	1.0000
Caucasian ethnicity	9/20 (45)	15/40 (37.5)	0.5896
Afro-Caribbean ethnicity	4/20 (20)	16/40 (40)	0.1536
Recipient age (yr)	49 (33.5-58)	48.5 (37.75-53)	0.8887
Pre-transplant diabetes	1/20 (5)	5/40 (12.5)	0.6532
Pre-transplant CVD	4/20 (20)	3/40 (7.5)	0.2077
Recipient CMV IgG positive	13/20 (65)	27/40 (67.5)	1.0000
Haemodialysis	9/20 (45)	19/40 (47.5)	1.0000
Peritoneal dialysis	6/20 (30)	7/40 (17.5)	0.3258
Pre-emptive transplant	2/20 (10)	6/40 (15)	0.7068
PRA test > 50%	6/20 (30)	12/40 (30)	1.0000
Primary transplant	17/20 (85)	36/40 (90)	0.6763
Deceased donor	13/20 (65)	25/40 (62.5)	1.0000
ABO-incompatible transplant	1/20 (5)	3/40 (7.5)	1.0000
Donor age (yr)	53.5 (42.25-62.75)	51 (40.75-57)	0.30302
Donor age ≥ 60 yr	8/20 (40)	9/40 (22.5)	0.2246
Donor CMV IgG positive	7/20 (35)	24/40 (60)	0.1004
CMV D+R- immunization	1/20 (5)	3/40 (7.5)	1.0000
Cold ischemia time (h)	14.25 (4.3-21.5)	12 (4-15)	0.4413
Cumulative HLA mismatch	3 (3-4.25)	3 (2-5)	0.4654
HLA mismatch > 4	5/20 (25)	11/40 (27.5)	1.0000
HLA-A mismatch	1 (1-1.25)	1 (1-2)	0.78716
HLA-B mismatch	1 (1-2)	1 (1-2)	0.25014
HLA-DR mismatch	1 (0-1.25)	1 (0-1.25)	0.8181
Induction immunosuppression
Anti-IL2-receptor antagonist	15/20 (75)	28/40 (70)
Anti-thymocyte globulin	4/20 (20)	9/40 (22.5)
Rituximab	1/20 (5)	3/40 (7.5)
Maintenance immunosuppression
CyA-based scheme	14/20 (70)	26/40 (65)
Tacrolimus-based scheme	6/20 (30)	14/40 (35)
MMF-containing scheme	19/20 (95)	35/40 (87.5)
AZA-containing scheme	1/20 (5)	5/40 (12.5)
CNI-free scheme	0/20 (0)	0/40 (0)
Steroid-free scheme	0/20 (0)	1/40 (2.5)
CMV prophylaxis	4/20 (20)	13/40 (32.5)	0.3752
DGF	6/20 (30)	9/40 (22.5)	0.5424
BPR within 30 d of transplant	4/20 (20)	9/40 (22.5)	1.0000
Initial viremia ≥ 10000 copies/mL	3/20 (15)	37/40 (92.5)	< 0.00001
Initial viral load (copies/mL)	6000 (2975-7550)	134800 (28750-425000)	< 0.00001
BKV viremia ≥ 3 wk	5/20 (25)	38/40 (95)	< 0.00001

PVAN: Polyomavirus-associated nephropathy; IQR: Interquartile range; BMI: Body mass index; CVD: Cardiovascular disease; CMV: Cytomegalovirus; IgG: Immunoglobulin class G; PRA: Panel-reactive antibody; HLA: Human leukocyte antigen; CyA: Cyclosporine; MMF: Mycophenolate mofetil; AZA: Azathioprine; CNI: Calcineurin inhibitor; DGF: Delayed graft function; BPR: Biopsy-proven rejection.