The purpose of this study is to estimate the cost-utility of continuous positive airway pressure (CPAP) therapy in obstructive sleep apnea (OSA) patients in Sao Paulo city, Brazil, after 3 years of treatment and to estimate the cost-effectiveness of CPAP on the number of medical visits, hospitalizations, medical examinations, used medications, new case incidence and cost of traffic accidents and absence from work. It is also designed to estimate quality-adjusted extended years of life, and to assess cost-effects of the therapy (device, masks, supplies, maintenance/year for membership of professional consulting, electric power) on the cost-effectiveness

OSA is highly prevalent in Sao Paulo city, Brazil. It is associated with significant comorbidities. The cost-utility study is important to (1) support decision-making on health policies, (2) to incorporate new technologies, (3) implementation of preventive programs and policy development assistance in the medical field.

Probably CPAP treatment in the long-term, will improve health, physical and mental state, and especially, reduces spending on public health, demonstrating cost-utility.

Inclusion Criteria:

• Both genders
• Aged 30 to 70 years old
• AHI > 30 events/hour

Exclusion Criteria:

• Patients residing in other cities and states other than São Paulo / SP / Brazil
• Patients with no fixed residence
• Previous CPAP contact