Methodology: Equivalence randomized comparative study . It will include patients with diagnosis of moderate-severe OSA (apnea-hypopnea Index >=15) that should start treatment with (CPAP). Participating center is Hospital Santa María-Arnau de Vilanova in Lleida (Spain).These patients will be randomized to two monitoring groups (1: monitoring in the Sleep disorders unit, 2: monitoring in primary care consultations) once the OSAS diagnosis has been made and it was indicated that treatment with CPAP. Patients Will be carried out in both groups the same follow-up visits in two study arms: basal, 1 month, 3 months and 6 months. Primary outcomes: number of hours of use per day (according to the accountant of the CPAP), so that use >= 4h/day is defined as good adherence to the treatment. Secondary outcomes: daytime sleepiness, patient satisfaction, Adverse events related to CPAP treatment. It will be collected demographic ,clinics and anthropometric variables. At the end of follow-up primary and secondary outcomes will be compared between two groups.