Retrospective Study for Description of The Use Of Omalizumab In Patients With Difficult To Control Asthma

The purpose of this study is do describe the experience in the use of omalizumabe, in a real life scenario, in uncontrolled severe asthmatic patients attended in specialist outpatient clinics, and its efficacy and safety. The efficacy of omalizumab in the population observed will be evaluated as reduction of uncontrolled asthma related events, i.e. exacerbations, emergency dept. visits, hospitalization and asthma-related treatment (decrease of asthma medication).