Prognostic importance of obstructive sleep apnea and CPAP treatment for cardiovascular and mortality outcomes in patients with resistant hypertension: a prospective cohort study

The prognostic importance of obstructive sleep apnea (OSA) severity and other polysomnographic parameters in patients with resistant hypertension (RHT) has never been evaluated. We aimed to assess it in a prospective cohort of 422 individuals with RHT. OSA presence/severity was ascertained by complete polysomnography (PSG) at baseline. Multivariable Cox regressions assessed the risks associated with OSA severity and other PSG parameters (apnea-hypopnea index, sleep duration, nocturnal hypoxemia and periodic limb movements) for the primary (total cardiovascular events [CVEs] and all-cause mortality) and secondary outcomes (major CVEs). In the subgroup of patients with moderate/severe OSA, the risks associated with CPAP treatment were also estimated in relation to untreated individuals. One-hundred and eighty-six participants (44%) had no/mild OSA and 236 (56%) had moderate/severe OSA, and 67 of them were CPAP-treated. Over a mean follow-up of 5 years, there were 46 CVEs (37 major ones) and 44 all-cause deaths. Neither the presence of moderate/severe or severe OSA, nor being untreated during follow-up, was associated with significant excess risks for any outcome in relation to the subgroup with no/mild OSA. Similarly, no other PSG-derived parameter predicted any adverse outcome. Otherwise, CPAP treatment was associated with non-significant risk reductions of 37% for total CVEs, 49% for major CVEs and 63% for all-cause mortality in relation to those who remained untreated during follow-up. In conclusion, the presence/severity of OSA and its related PSG parameters were not associated with worse cardiovascular/mortality prognosis in patients with RHT. However, CPAP treatment might be protective in individuals with moderate/severe OSA.