Comparative studies of inhaled corticosteroids in asthma.

With inhaled corticosteroids being the mainstay of anti-inflammatory treatment in asthma, it is necessary to determine the comparative efficacy and safety of different corticosteroids delivered through different inhaler devices. Over recent years this has assumed considerable importance, with the phasing out of metered dose inhalers using chlorofluorocarbon (CFC) propellants, and with the availability of an increasing number of different dry powder devices or aerosol metered dose inhalers in which alternative hydrofluoroalkane (HFA) propellants have been used. This has led to numerous studies in which the efficacy of inhaled corticosteroid preparations, either dry powder or HFA- containing aerosol metered dose inhalers, have been compared with the same or different inhaled corticosteroids via standard CFC-containing preparations in current use. Although numerous study designs are available for such comparisons, that most commonly employed has been single high dose comparisons, with the lack of statistical significant differences between the two preparations being proposed to indicate …