Table 2.

Cox regression model of grades III–IV acute GVHD, stratifying on DRB1 match status

Factor	RR	95% CI	P value*
DQB1 mismatch†	1.6	1.1, 2.3	0.02
Parous female donor and male patient	1.7	1.1, 2.4	<0.01
Dose of TBI >1200 cGy	1.3	0.91, 1.7	0.17

Eight strata were modeled based on patient age (≥36 versus <36 years), transplant year (1991–1992 versus all other), and DRB1 match/mismatch status. CI, confidence interval. 

^*P values correspond to the test of the null hypothesis that the RR = 1.0. 

^†Likelihood ratio test P value for the contribution of DQB1 mismatch on this model is 0.03.