Complex sleep apnea during CPAP titration: prevalence and predictive factors

Abstract

INTRODUCTION Obstructive sleep apnea syndrome (OSAS) patients may develop central apneas during initiation of continuous positive airway pressure (CPAP) (1). This is referred to as complex sleep apnea (CSA). To assess the prevalence of CSA during CPAP titration and to identify potential predictive factors. Materials and methods Data of consecutive patients attending a general hospital sleep laboratory spanning 15 months (January 2012 to March 2013), diagnosed with OSAS after a first full-night polysomnography (PSG) were retrospectively reviewed. All patients underwent a PSG monitored CPAP titration. Patients with a central apnea index (CAI) ⩾ 5/hour during the CPAP titration (2) were compared to the remainders. Chi2 tests and multivariate logistic regression were carried out. Results A sample of 263 patients (184 males, mean age 54.8) was eligible for analysis. The prevalence of CSA [95% confidence interval (CI)] during CPAP titration was 9.1% [5.6–12.6]. CSA patients presented with a significantly higher prevalence of cardiac insufficiency (16.3% vs. 3.3%; p=.016). Other co-morbidities were similar between groups. Diagnostic PSG showed a higher median apnea hypopnea index (51.7 vs. 30.3; p=.054), a higher median mixed apnea index (MAI) (2.3 vs. 0.3; p=.001), and a higher median CAI (3.9 vs. 0.3; p .001). Multivariate analysis showed solely the increase of 1 unit of CAI and/or MAI before CPAP being associated with a higher probability for the occurrence of CSA with respective odds ratio (95%CI) of 1.05(1.00–1.10) and 1.09(1.01–1.18). Conclusion About 1 in every 10 patients has CSA during CPAP titration. Independent predictive factors of CSA include higher CAI and higher MAI before CPAP titration.