The adjusted responder rate estimate during maintenance ( logistic regression adjusting for treatment group , pooled center , and pain intensity at start of maintenance ) was significantly higher with tapentadol PR ( 64.3 % ) than with placebo ( 47.1 % ; odds ratio ( OR ) , 2.02 [ 95 % confidence interval ( CI ) , 1.12 - 3.65 ] ; P = 0.02 ) .