Adherence to Continuous Positive Airway Pressure therapy in Singaporean patients with Obstructive Sleep Apnea

Purpose: To investigate the rates of Continuous Positive Airway Pressure (CPAP) uptake and adherence amongst Singaporean patients diagnosed with Obstructive Sleep Apnea (OSA), and to evaluate factors correlated with CPAP uptake and adherence. Study design: Retrospective review of medical records. Methods: Medical records were reviewed for baseline demographics, daytime sleepiness, presence of nasal symptoms and OSA severity, initial treatment choice, the rate of CPAP treatment uptake and CPAP adherence at 1 and 12 months. Results: 2160 patients were diagnosed with OSA within the 5-year period (2011-2015). 463 (21.4%) had mild OSA, 583 (27.0%) had moderate OSA and 1114 (51.6%) had severe OSA. For initial therapy, 751 (34.8%) patients opted for a 1-month CPAP trial, 288 (13.3%) patients chose surgery upfront, 291 (13.5%) patients chose adjunctive treatments (weight loss, positional therapy, dental appliance, intranasal steroid spray for allergic rhinitis) and 830 (38.4%) patients rejected all forms of treatment. 337 out of 751 patients (44.9%) were adherent to CPAP therapy during the 1 month trial. 381 out of 751 (50.7%) patients took up CPAP therapy following the trial period, of which 299 out of 381 (78.5%) patients were adherent to CPAP therapy at 1 year. CPAP adherence during the 1-month trial was a predictor for eventual CPAP treatment uptake and CPAP adherence at 1 year (p < 0.001). Age (p < 0.001), BMI (p < 0.001) and normal ESS (p = 0.01) were predictors of treatment rejection. 24 patients underwent upper airway surgery during their first year of using CPAP. 21 out of the 24 patients (87.5%) were adherent to CPAP at 1 year after undergoing surgery. These patients had a higher rate of CPAP adherence compared to the overall cohort (87.5% versus 78.5%), but this was not statistically significant (p > 0.05). Conclusion: Singaporean patients who accept CPAP therapy after an initial 1-month CPAP trial will generally be adherent to CPAP therapy. Initial patterns of CPAP usage are predictive of long term CPAP adherence. However, there is a high rate of CPAP treatment rejection both at the time of diagnosis and after the CPAP trial. Upper airway surgery in selected patients may improve CPAP adherence.