The optimal score to predict unfavourable outcome in well-controlled asthma patients who are undergoing a step-wise down-titration of their medication is still lacking. Thus, a study is warranted to prospectively develop a prognostic system -easy to perform (suitable for use in the clinical rather the research setting)- for asthmatic patients in this clinical setting.

HYPOTHESIS: A simple score system can accurately predict clinical deterioration of asthma in well-controlled patients who are undergoing a step-wise down-titration of their medication according to international guidelines.

METHODS The investigators designed a prospective, multicenter, observational study at five centers in cities across Spain.

The patients group (N = 225) will be evaluated to produce a clinical prediction rule for loss of control. The investigators will consider the following variables in the risk factor analysis: documented history of previous bronchial obstruction (FEV1/FVC < 70%), coefficient of variation (CV) of morning peak expiratory flow (PEF), history of exacerbations, fraction of exhaled nitric oxide (FENO), Asthma control test (ACT), ACT item 3 and adherence.

The score model will be prospectively validated in an independent set of 113 patients.

Inclusion Criteria:

• Adults (age between 18 and 80.
• Asthma under control during the last 3 months.
• Treated with a combination of ICS and long-acting beta-agonist (LABA.
• Classified as "moderate asthma" by their attending physician.

Exclusion Criteria:

• Active smoking.
• Pregnancy.
• Treatment with oral corticosteroids, omalizumab or immunotherapy.

Well-controlled asthmatics who are regularly under the care of Allergy or Pneumology specialists.