OSA is an independent risk factor for AF, approximately doubling the risk.35 A review of 10,132 patients with AF (1841 with OSA) in a large observational study demonstrated no difference in outcomes of all-cause mortality, first hospitalization, major bleeding, or major cardiovascular events in OSA patients who were or were not treated with PAP. The PAP-treated patients did have a slightly lower (16% vs 18%) risk of worsening of AF over 2 years.36 Overall, AF patients with OSA had more symptoms and higher admission rates, but no difference in overall mortality or MACE. Observational studies have suggested that PAP treatment of OSA facilitates maintenance of normal sinus rhythm after cardioversion and after ablation.37
CHF: Results look promising
In one small study, 24 patients with heart failure with reduced ejection fraction who were optimally medically treated were randomized to receive PAP or sham PAP for 1 month.38 The treatment group demonstrated reduced systolic BP, reduced end systolic dimension, and significant improvement in ejection fraction from 25 ± 2.8% to 33.8 ± 2.4%.
OSA Tx improves insulin sensitivity
OSA is associated with impaired glucose tolerance, and PAP treatment of OSA has been documented to improve insulin sensitivity.39,40 An efficacy study utilizing PAP in a laboratory setting for 8 hours/night demonstrated significant reduction in fasting blood sugar and a reduction in the dawn phenomenon (an increase in early morning fasting glucose as a result of rebound from hypoglycemia during sleep).39 A 2015 meta-analysis of short-term studies also showed improvement in insulin sensitivity in OSA patients treated with PAP, but failed to find any reduction in A1C or in body mass index.40
All-cause mortality: Difference in findings between short- and long-term studies
Yu et al’s34 meta-analysis of 10 RCTs involving 7266 participants found no difference in mortality in treated (vs no treatment or sham treatment) OSA patients. This was true even in the more adherent subgroup. These studies were relatively short-term, with the longest mean follow-up being 68 months.
Offer a trial of treatment with PAP to asymptomatic patients with moderate-to-severe OSA and comorbidities, such as obesity, resistant hypertension, CHF, atrial fibrillation, and diabetes.
However, several longer-term population-based studies have suggested that OSA treatment improves all-cause mortality. An 18-year follow-up of a Wisconsin cohort documented dramatically increased mortality in patients with severe sleep apnea; mortality was even higher when patients treated with PAP were removed from the analysis, suggesting that PAP treatment was protective, mainly for cardiovascular death.5
