title: Clinical trials in acute severe asthma: are type II errors important?
abstract: Many studies in acute severe asthma have had low power. Fifteen randomised double blind studies investigating the treatment of acute severe asthma published during 1974-84 were analysed for power and 95% confidence limits. Twelve studies failed to detect a significant difference in bronchodilatation produced by two treatments and reported the treatments to produce equal effect. Each study had, however, less than a 60% probability of detecting a true 25% difference in bronchodilatation.
mesh_terms: D000208:Acute Disease; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D006801:Humans; D010366:Peak Expiratory Flow Rate; D011897:Random Allocation; D013223:Statistics as Topic
chemical_list: D000305:Adrenal Cortex Hormones; D001993:Bronchodilator Agents