The main outcomes of this study are to establish a cohort of well-phenotyped asthma patients with a recent history of an exacerbation. We aim to describe exacerbation profiles (phenotypes) of the cohort in terms of inflammatory/biomarker profile and bacterial/viral infection status and to compare these with exacerbation events in the sister APEX cohort.

This is a single centre, observational, longitudinal cohort study. The study will consist of one group of approximately 200 patients with clinician diagnosed asthma, who have had at least one exacerbation in the past year before informed consent. They will be identified from secondary care, primary care and the Nottingham Respiratory Research Database (NRRD).

After the Baseline visit, each subject will be followed for the duration of their participation in the study. Participants will be asked to contact the research team if they perceive that their asthma symptoms are worsening to the extent that they would usually seek help from a healthcare professional. They will then be invited to attend the Assessment Visit and potential Exacerbation Visit. Participants who complete this visit will then continue in the study, as we are interested in comparing subsequent events in the same individuals, to establish exacerbation stability and consistency.

All participants, whether they have attended an Assessment visit or not, will be invited to attend for an Annual visit. The research team will also contact participants at 3 monthly intervals, with their permission, to discuss the study and provide updates.

INCLUSION

• Clinician diagnosed asthma.
• Male or female aged ≥ 18 and ≤ 85 years of age.
• One asthma exacerbation requiring additional treatment in the year prior to informed consent. This is defined as either: 3 or more consecutive day's treatment with oral corticosteroids; for participants not on maintenance steroids, OR at least a doubling of treatment with oral corticosteroids for 3 or more consecutive days, from a stable dose, for participants on maintenance therapy with oral corticosteroids. These can be patient-reported.
• On British Thoracic Society (BTS) step 1-5 treatment
• Current smokers can be included, provided there is good evidence of underlying asthma (for example, a life-long history of asthma, > 12% FEV1 reversibility or sputum or blood eosinophilia).
• Able (in the Investigator's opinion) and willing to comply, with all clinical investigation requirements.
• Non-English speaking participants should be proficient in their understanding of the English language, in order to be able to fully participate in the study.

EXCLUSION:

• Exacerbation in the 4 weeks prior to the Baseline visit. The use of biologic therapy, including Omalizumab, Mepolizumab or Benralizumab, at any time during the 3 months.
• prior to informed consent. Participants who commence biologic therapy during the course of the study will be withdrawn.
• A history more in keeping with smoking-related Chronic Obstructive Pulmonary Disease (COPD)
• Other clinically significant respiratory diseases.
• Use of regular high dose maintenance systemic corticosteroids (for example, a dose of > 10mgs of Prednisolone daily)
• Any other clinically significant medical disease or uncontrolled concomitant disease, that is likely, in the opinion of the investigator, to impact on the ability to participate in the study or the study results.
• Pregnant women, lactating women or women who are planning to become pregnant.
• Participants with uncontrolled hypertension. Participation in a study involving an investigational medicinal product at any time during the 3 months prior to informed consent.

A population of asthmatics who have had an exacerbation in the 12 months prior to the study