RESUMEN
Background: The use of CPAP is the conventional therapy for the Obstructive Sleep Apnea Syndrome (OSAS). Aim To establish the proportion of OSAS patients with CPAP indication who use it in the long-term and to determine predictive factors of adherence. Patients and Methods: Structured survey through personal interview or phone call, applied to all patients who had polisomnographically documented OSAS and CPAP titration at the Pontificia Universidad Católica de Chile Sleep Disorders Center between January 1998 and November 2001. Patients were divided in "Permanent Users" (Group I) and "Non Users" (Group II). Results: Of 440 patients that fulfilled inclusion criteria, 162 (32.8 percent) answered the survey. Seventy percent (114/162) of these patients had used CPAP and 86 percent (98/114) continued to use it at the time of the interview, with a mean follow-up of 12.3 months (Group I 60.5 percent of the interviewed population). Group II included 64 patients (39.5 percent of the interviewed patients). Among the latter, 25 percent (16/64) stopped using CPAP due to intolerance, 25 percent (16/64) could not use it because of economical restrictions, 20.5 percent (13/64) preferred other therapies and 29.5 percent (15/64) merely refused treatment. Predictors of long-term use of CPAP were number of respiratory events (p <0.01), hypersomnolence (p <0.01) and age (p =0.03). Conclusions: Approximately two thirds of patients with OSAS, with an indication for CPAP, continue to use this therapy in the long term in a Chilean population. This figure is similar to other reports from abroad. It is also possible to identify predictive factors for CPAP discontinuation in this population.