Statistically significant associations were identified between grade 3 or greater 5FU-AEs and both DPYD * 2A ( odds ratio [ OR ] = 15.21 , 95 % confidence interval [ CI ] = 4.54 to 50.96 , P < .001 ) and D949V ( OR = 9.10 , 95 % CI = 3.43 to 24.10 , P < .001 ) variants .