Table 3. Univariate Analyses Assessing the Association of Time-Varying Exposures with Subsequent Hemorrhagic Cystitis.

Variable	Hazard Ratio (95% Confidence Interval)	P Value
Primary Exposures
Peak BK plasma PCR*
0 copies/mL	0.9 (.3 to 2.5)	.83
1 to 9999 copies/ml	5.3 (2.0 to 14.6)	<.01
10,000 to 99,999 copies/mL	No cystitis subject met this criterion
≥100,000 copies/mL	34.3 (4.6 to 256.1)	<.01
Secondary Exposures
Graft-versus-host disease	1.0 (.2 to 4.9)	.99
Thrombotic microangiopathy	2.2 (.7 to 6.9)	.18
Neutrophil engraftment	.6 (.1 to 2.7)	.49
Platelet engraftment > 20,000/μL	.4 (.1 to 1.3)	.12
Platelet engraftment > 50,000/μL	.3 (.1 to 1.4)	.14
Adenoviremia > 0 copies/mL	1.3 (.4 to 4.7)	.70
CMV viremia > 0 copies/mL	1.6 (.4 to 5.8)	.48
EBV viremia > 0 copies/mL	2.1 (.6 to 7.8)	.26
HHV-6 viremia > 0 copies/mL	7.6 (2.6 to 22.2)	<.01

CMV indicates cytomegalovirus; EBV, Epstein-Barr virus. Boldface indicates statistically significant.

^*Peak BK plasma PCR before cystitis in the hemorrhagic cystitis group and anytime during the first 100 days in the noncystitis group. For subjects with more than 1 identical peak value, the first date was used in the analysis.