The percentage of heartburn-free 24-hour days over 14 days was significantly higher ( P < 0.0001 ) in subjects receiving esomeprazole 20 mg compared with placebo in study 1 ( N = 331 ; 46.13 % vs. 33.07 % , respectively ) and study 2 ( N = 320 ; 48.00 % vs 32.75 % , respectively ) .