CPM increased from 9.1 ( 5.4 ) % ( baseline ) to 14.3 ( 7.2 ) % ( placebo ) and 24.2 ( 7.7 ) % ( tapentadol SR , P < 0.001 vs placebo ) ; relief of DPN pain was also greater in patients treated with tapentadol than placebo ( P = 0.028 ) .