Moreover, the economic burden of asthma is increasing. In the US, it is estimated that the yearly cost of asthma in children and adults is around $1.48 billion (Price et al., 2013). A decade ago, the total annual asthma expenditure in the UK was determined to be £752.6 million with 8% of costs associated with hospital admission, 13% attributable to general practitioner consultations and 79% due to prescription costs (Gupta et al., 2004).