SHORT-TERM AND LONG-TERM EFFICACY

In clinical studies of asthma, great attention should be focused on th e choice and validation of outcome measures, The outcome parameters to be used when evaluating efficacy of early intervention in childhood a sthma treatment must be closely linked to the aims of the intervention and considered in the design of the study, In an interventional study , possible adverse consequences should also be considered as outcome m easures when designing the study. The appropriate time span for assess ing different types of interventions may vary from days to several dec ades, depending on the character of the intervention, Not only outcome parameters, such as improvement in symptom score and improvement of l ung function, but also those that measure reduction in frequency and s everity of acute exacerbations, reduction in morbidity and improvement in quality of life should be used. For some purposes, a more detailed approach to symptom severity is needed, such as separation of acute f rom chronic symptoms, Other outcome measures that need to be considere d are: cost-effectiveness, normalization of inflammatory changes in th e airways, control of airway hyperresponsiveness airway growth and pre vention of airway remodelling and importantly, whether an intervention against asthma can alter the natural course, or cure, the disease. In terventions should be evaluated to see to what extent such aims have b een met.