Methotrexate for Asthma

Excerpt

To the Editors: We are concerned that Erzurum and colleagues (1) drew the conclusion that methotrexate is not beneficial in severe asthma without recognizing the implications of their small sample size. We suggest that the 18-patient sample size was inadequate to show a significant benefit of methotrexate on asthma control. Using the sample size analysis of Young and colleagues (2) with significance levels of α = 0.05 and β = 0.2, this study would have required a sample size of approximately 100 patients in order to detect a 50% difference in steroid dose between the two groups. Thus, it is