Cardiovascular mortality in obstructive sleep apnoea treated with continuous positive airway pressure or oral appliance: An observational study

Background and objective The objective of this study was to evaluate the long‐term cardiovascular mortality in patients with severe obstructive sleep apnoea ( OSA ) treated with either continuous positive airway pressure ( CPAP ) or mandibular advancing device ( MAD ). Methods A non‐concurrent cohort study of 570 subjects with severe OSA (apnoea/hypopnoea index ( AHI ) ≥ 30/h) and a control group of 269 subjects ( AHI  < 5/h) were followed up for a median of 79 months (interquartile range 76–88 months). All patients received CPAP initially. MAD was offered for those who were non‐adherent to CPAP . The endpoint was cardiovascular death. Results  Two hundred and eight control subjects, 177 patients treated with CPAP , 72 with MAD and 212 who declined treatment were analysed. Forty‐two patients had a fatal cardiovascular event during the course of the study. The non‐apnoeic group had the lowest cardiovascular death rate (0.28 per 100 person‐years (95% confidence interval ( CI ): 0.08–0.71)) followed by the CPAP ‐treated (0.56 per 100 person‐years (95% CI : 0.20–1.23)) and the MAD ‐treated OSA group (0.61 per 100 person‐years (95% CI : 0.13–1.78)), with the highest cardiovascular mortality rate observed in the untreated OSA group (2.1 per 100 person‐years (95% CI : 1.37–2.92)). Although residual AHI for MAD ‐treated patients was significantly higher than CPAP ‐treated patients (16.3 ± 5.1/h vs. 4.5 ± 2.3/h; P  < 0.001), there was no difference in cardiovascular death rate between the two groups (hazard ratio 1.08 (95% CI : 0.55–1.74); P  = 0.71). Conclusions Both CPAP and MAD may be equally effective therapy in reducing the risk of fatal cardiovascular events in patients with severe OSA .