In the salmeterol group , patients with Arg16Arg genotype had a significantly reduced exacerbation risk compared with patients with Arg16Gly ( p = 00130 ) and Gly16Gly ( p = 00018 ) genotypes ( proportion of patients with at least one exacerbation was 323 % in Arg16Arg , 398 % in Arg16Gly , and 421 % in Gly16Gly ) .