New method of evaluating patient preference for different inhalation delivery systems

In order to assess patients' preferences for different inhalation devices a questionnaire has been developed. The questionnaire consisted of items covering various aspects considered important for patients who regularly use inhalation devices. The questions were designed to be of a general character so any inhalation device could be evaluated. We evaluated the questionnaire in a multicenter, open crossover study comparing patients' opinions of MDI with and without spacer and of a dry powder inhaler, Turbuhaler. One hundred twenty-three patients with stable asthma confirmed by daily peak expiratory flow rate (PEF) measurements used for 2 weeks MDI only and MDI with spacer and for 2 weeks Turbuhaler. The order was randomized. The drugs were terbutaline inhaled via MDI and Turbuhaler and budesonide inhaled via MDI with spacer and turbuhaler. At the end of each evaluation period the patients answered a number of questions about their opinion by marking on a visual analogue scale. A factor analysis revealed that the different questions represent a few common factors important for evaluating opinion about inhalation devices. These factors are handling of the device, use, time to learn how to use the device properly, how confident the patients feel about the use of it, and taste/irritation. A standardized questionnaire of reduced size seems to be a suitable method for evaluating patient preference for different inhalation devices.