Asthma affects an estimated 300 million people worldwide with a population prevalence of ca 15% in the UK. The WHO has estimated UK disability adjusted life-years per 100,000 population for asthma to be greater than diabetes and breast cancer. Much of this excessive disability is in the 10-20% of patients with asthma which is difficult to control despite currently available therapies. This high morbidity and disproportionate use of health care resources reflects the considerable unmet need in this patient group, and their significance for health care providers.~Asthma has been traditionally 'stratified' on the basis of response to 'step-wise' incremental treatment with inhaled corticosteroid (ICS) therapy forming the cornerstone of this approach. However, more recently, asthma has been stratified on the basis of inflammatory phenotype to better understand disease heterogeneity with a view to developing biomarkers of therapeutic response and for the better targeting of both new and existing treatments.~Investigators have recently examined the predictive value of a composite biomarker strategy using FeNO, blood eosinophils and serum periostin together to predict exacerbation risk in the placebo arms of clinical trials. Investigators propose to examine if this composite biomarker strategy predicts exacerbation risk in patients with asthma on high dose ICS (+/-long-acting beta agonist) treatment and to evaluate the utility of this composite score to facilitate personalised biomarker specific titration of corticosteroid therapy in this population. This study will examine subjects with FeNO<45 ppb and the scoring system will potentially allow identification of a 'low-risk' group who can safely reduce corticosteroid dose. This study will address a second important question of estimating the proportion of patients with severe disease who develop typical (T2)-driven eosinophilic inflammation on progressive corticosteroid withdrawal.
This study explores if a composite biomarker strategy predicts exacerbation risk in patients with asthma on high dose inhaled corticosteroid (+/-long-acting beta agonist) treatment and to evaluate the utility of this composite score to facilitate personalised biomarker specific titration of corticosteroid therapy in this population.