Table 1. Baseline demographic and clinical characteristics of the study sample of Medicare-insured live donor kidney transplant recipients according to ABO compatibility.

	ABOi (N =271)	A2i (N =62)	Compatible(N = 26504)
Recipient Characteristics	% or mean +/- SD	% or mean +/- SD	% or mean +/- SD
Age	*
<=18	2.21	3.23	4.89
19-30	14.02	19.35	15.74
31-44	18.08	29.03	23.64
45-59	32.84	17.74	29.51
>=60	32.84	30.65	26.22
Female sex	37.64	41.94	40.45
Race
White	64.94	70.97	69.33
Black	20.66	17.74	17.71
Other	14.39	11.29	12.97
BMI (kg/m2)
10 to 18.5	4.43	4.84	5.25
18.5 to 25	33.21	40.32	34.64
25 to 30	31.37	25.81	29.87
>30	21.77	19.35	24.58
Cause of ESRD
Diabetes	23.25	19.35	22.15
Glomerulonephritis	17.34	33.87	21.18
Hypertension	15.13	12.90	18.19
Polycystic kidney disease	7.38	4.84	6.62
Other	36.90	29.03	31.87
Previous transplant	22.51‡	12.90	12.02
Pretransplant dialysis
Preemptive	15.87	11.29	16.66
>0-24	35.06	37.10	41.24
25-60	28.41	35.48	26.73
>60	18.45	14.52	13.84
Peak panel reactive antibody level	‡
< 10	58.30	64.52	74.80
10–79	20.30	20.97	16.47
>=80	11.44	6.45	4.35
Missing	9.96	8.06	4.39
HLA mismatches
Zero A, B, and DR	10.33	6.45	8.30
Zero DR	18.82	8.06	18.44
Cytomegalovirus
Recipient + / Donor +		37.27	38.71	36.13
Recipient + / Donor -		25.83	20.97	19.21
Recipient - / Donor +		9.59	16.13	14.14
Recipient - / Donor -		17.34	17.74	18.10
Year of Transplant		‡	*
2000-2005		35.42	41.94	55.61
2006-2011		64.58	58.06	44.39
Donor Characteristics
Age, mean (SD), yr		43.58 (12.12)‡	40.71 (11.97)	39.97 (11.30)
Female		60.52	66.13	59.84
Race
White		69.00	80.65	70.65
Black		17.34	11.29	15.71
Other		13.65	8.06	13.65
Induction		67.16	88.71‡	63.39
Steroids at discharge		74.91	75.81	72.71
Maintenance ISx at discharge		‡	*
Tacrolimus and MMF		79.34	82.26	62.63
Rapamycin-based		5.17	1.61	9.95
Other		15.50	16.13	27.41

P-values for comparisons of trait distribution in ABOi or A2-to-O groups versus compatible transplants:

P-values:

^*P 0.002–0.04;

^†P 0.0001–0.001;

^‡P < 0.0001