Objective: Obstructive sleep apnea (OSA) and hypertension (HYP) frequently coexist and have additive harmful effects on the cardiovascular system. There is also growing evidence that short sleep duration may contribute independently to poor cardiovascular outcome. The aim of this study was to evaluate the potential influence of antihypertensive medication on sleep parameters objectively measured by standard polysomnography in hypertensive patients with OSA.
Methods: We evaluated consecutive patients with a recent diagnosis of OSA by full polysomnography (apnea hypopnea index ≥ 5 events/h) and HYP. Smokers, patients with diabetes mellitus, heart failure, or using hypnotics and benzodiazepines were excluded.
Results: We evaluated 186 hypertensive patients with OSA, 64% men. All patients were on at least one antihypertensive medication, including angiotensin-converting enzyme inhibitors (37%), beta-blockers (35%), angiotensin receptor blockers (32%), diuretics (29%) and calcium channel blockers (21%). Backward multiple regression analysis showed that age (P ≤ 0.001) and the use of calcium channel blockers (P = 0.037) were the only factors inversely associated with lower total sleep time. Sleep efficiency was inversely associated only with age (P ≤ 0.001), whereas the use of calcium channel blockers had a nonsignificant trend (P = 0.092). Use of calcium channel blockers was associated with significant reduction in total sleep time (-41 min, P = 0.005) and 8% lower sleep efficiency (P = 0.004). No other antihypertensive medication, including diuretics and beta-blockers, was associated with sleep impairment.
Conclusion: Calcium channel blockers may impact negatively on sleep duration in hypertensive patients with OSA. The mechanisms and significance of this novel finding warrants further investigation.