Sample size estimation
cough
REMISSION
According to our previous treatment of 11 patients diagnosed with refractory cough with duloxetine hydrochloride enteric-coated tablets at 20 mg TID, seven patients had more than 50% relief from the their cough, and some patients even enjoyed full relief of their cough. The remission rate was 63%. Placebo was 30% effective for refractory cough. According to the estimation formula of the sample size for the comparison of the two sample rates, a two-sided test will be performed at the level of significance of 0.05 and the level of statistical power of 0.8. The number of observed cases needed in each group is 42, so with an estimated loss to follow-up rate of 15%, the number of cases to be observed in each group is 49. A total of 98 cases of refractory cough which seek medical treatment in Tongji Hospital, School of Medicine are needed in the study to detect true results at a statistical significance level of 5%.