Table 3.

Multivariate Cox regression analysis for the factors associated with the development of BK viremia^a

Models	HR	95% CI	P-value
Recipient age (years)b	0.77	0.26–2.40	0.65
Recipient gender (male)	2.38	1.46–4.09	<0.001
Maintenance IS (Tac monotherapy)	0.68	0.44–1.07	0.094
Acute rejection episodec	0.96	0.58–1.56	0.89
HLA mismatch (4–6)	0.77	0.49–1.24	0.28
HLA-A2 match	0.51	0.28–0.85	0.011
B44 match	0.31	0.076–0.85	0.019
C6 match	0.24	0.013–1.12	0.075
DQ7 match	1.63	0.91–2.78	0.097
DR7 match	0.49	0.12–1.36	0.19
DR15 match	0.35	0.084–0.93	0.034

HR: hazard ratio, CI: confidence interval, IS: immunosuppression, Tac: tacrolimus.

^aData in this table include all patients since 2002. Since routine screening for BKV infection was commenced only in 2006, we performed a sub-analysis based only on this subset of 709 patients. Male gender (HR 2.40, P = 0.002), HLA-A2 match (HR 0.51, P = 0.026), HLA-B44 match (HR 0.36, P = 0.048) and HLA-DR15 match (HR 0.26, P = 0.021) remained statistically significant.

^bRecipient age, gender and specific variables associated with P-values <0.1 by univariate analysis with Student's t-test, chi-square test or Fisher's exact probability test (Tables 1 and 2) were entered in this multivariate analysis.

One hundred and five patients were excluded from this analysis because of the missing data in HLA-C and/or HLA-DQ.

^cIn our analysis of rejection as a risk factor of viremia, rejection episodes that occurred after the viral clearance were excluded from consideration, however, the effect of male gender (HR 2.35, P < 0.001), HLA-A2 match (HR 0.51, P = 0.010), HLA-B44 match (HR 0.31, P = 0.019) and HLA-DE15 match (HR 0.35, P = 0.034) remained statistically significant even if this exclusion was not performed.