The RVPAS versus MBTS treatment effect had nonproportional hazards ( P = 0.004 ) ; the hazard ratio favored the RVPAS before 5 months ( hazard ratio = 0.63 ; 95 % confidence interval , 0.45-0 .88 ) but the MBTS beyond 1 year ( hazard ratio = 2.22 ; 95 % confidence interval , 1.07-4 .62 ) .