Considerable evidence supports the link between sleep disturbance and cardiovascular disease.1 Obstructive sleep apnea (OSA), in particular, is associated with cardiovascular morbidity and mortality,2 and thus, one might reason that effective treatment of OSA represents an important target for improving cardiovascular risk.
Should OSA then be actively diagnosed and treated in all patients with cardiovascular risk? To make such a recommendation, large-scale randomized controlled trials (RCTs) demonstrating the benefits of OSA treatment with respect to cardiovascular outcomes would be necessary. However, the design of such OSA RCTs assessing hard cardiac end points (eg, cardiac events and death) is challenging because of ethical and logistic considerations. Randomizing patients with severe symptomatic OSA to long periods off therapy may be problematic when considerable evidence shows symptomatic benefit of nasal continuous positive airway pressure (CPAP).3 An alternative would be to design shorter-term RCTs using surrogate biomarkers of cardiovascular events as end points.