The CPASMA trial is a descriptive, prospective, multicentre clinical trial, with a before/after Continuous Positive Airway Pressure (CPAP) assessment in participating patients. It aims to answer the following question: Is there an improvement in asthma in those patients with both asthma and obstructive sleep apnoea syndrome (OSAS) treated with CPAP after six months?. It is hypothesized that treatment of OSAS with CPAP in patients with both OSAS and asthma concommitantly, may have a beneficial effect also on asthma outcomes. This clinical effect in asthma could be assessed objectively by applying validated questionnaires for quality of life and asthma control.

Full protocol in Spanish, available upon request

Inclusion Criteria:

• Adult patients (18 to 70 yrs.) with asthma who require treatment with CPAP because of OSAS (RDI> = 20 events per hour)

Exclusion Criteria:

• unstable or severe comorbidity,
• patients in treatment with drugs that interfere with the clinical course of asthma and/or OSAS,
• cognitive/psychiatric disorders that preclude patient participation/cooperation,
• COPD or other lung disease accompanied by chronic airflow limitation, and
• any clinical condition considered severe enough by the investigators to preclude all the diagnostic and therapeutic procedures outlined in this protocol.