Longitudinally , changes in SAQ angina frequency scores from day 1 to week 8 also correlated with changes in angina frequency ( -0.42 ; 95 % confidence interval , -0.48 to -0.30 ) and SL NTG use by diary ( -0.38 ; 95 % confidence interval , -0.43 to -0.32 ) over the corresponding time period .