Study objective: To assess the effect of 1 year of therapy for sleep apnea syndrome (SAS) combining domiciliary nasal-continuous positive airway pressure (N-CPAP) and attempted weight loss on the severity of disease and to evaluate the potential for weaning from continuous positive airway pressure (CPAP).
Methods and procedures: Ninety-five patients having a baseline apnea hypopnea index (AHI) greater than 10/h were prescribed N-CPAP at home. Weight loss was attempted by dietary counseling and by single ring vertical gastroplasty in those patients with a body mass index (BMI) greater than 40 kg/m2. Subjects were asked to return after 1 year for a full-night polysomnography (PSG) without CPAP and the results were compared with baseline PSG.
Results: Thirty-nine patients compliant to CPAP were evaluated. Weight had decreased from 108.3 +/- 29.0 to 99.7 +/- 17.7 kg as a result of dietary counseling (n = 36) or gastroplasty (n = 3). A significant improvement was found in AHI (66.5 +/- 28.7-->50.3 +/- 38.4/h; p < 0.05), maximal duration of apnea or hypopnea (66 +/- 22-->47 +/- 18 s; p < 0.001), minimal oxyhemoglobin saturation (62 +/- 16-->78 +/- 7%; p < 0.001), and stage shift index (SSI) (76 +/- 29-->62 +/- 28/h; p < 0.05). The drop in AHI correlated with the reduction in BMI (r = 0.47; p < 0.01) and with the decrease in SSI (r = 0.50; p < 0.001). Weaning from CPAP was proposed to six patients and succeeded in four (three with 29, 93, and 94 kg weight loss, respectively, and one subject with a normal unchanged weight).
Conclusion: In 39 patients with SAS, 1-year domiciliary N-CPAP combined with weight loss resulted in a significant improvement in breathing during sleep and in sleep fragmentation, as judged from PSG without CPAP. Four subjects were successfully weaned, three of whom had in parallel a substantial decrease in weight.