Night-time BP alters link between CVD risk, sleep duration

Night-time home blood pressure (BP) modifies the interaction between sleep duration and cardiovascular disease (CVD) risk, a recent study has found.

The researchers used self-reported sleep duration data from 2,236 ambulatory outpatients (mean age 63.0 years, 50.4 percent men) who had at least one CVD risk factor. A cuff oscillometric device was used to measure home BP over 14 days. CVD outcomes included stroke and coronary artery disease (CAD).

At baseline, 83 percent of participants were on antihypertensive medication. Most of them (84 percent) reported sleeping ≥6 and <9 hours per night. Patients were followed up for a mean of 7.1 years (15,896 person-years), during which 52 strokes and 81 CAD events occurred, yielding a total of 133 atherosclerotic CVD events.

Kaplan-Meier curves revealed a significant interaction between CVD events and sleep duration. In particular, the risk of total CVD events (p=0.029) and stroke (p=0.031) was significantly elevated in participants who slept for <6 hours per night relative to those with ≥6 and <9 hours of sleep per night. No such effect was reported for CAD.

Cox proportional hazards analysis additionally demonstrated that night-time systolic BP modified the interaction between sleep duration and CVD risk. For instance, among participants with systolic BP <120 mm Hg, short sleep increased the risk of total CVD (hazard ratio [HR], 3.46, 95 percent confidence interval [CI], 1.52–7.92) and CAD (HR, 3.24, 95 percent CI, 1.21–8.69).

Even among participants who slept for the optimal duration of ≥6 and <9 hours per night, uncontrolled night-time systolic BP (≥120 mm Hg) significantly raised the risk of stroke (HR, 2.76, 95 percent CI, 1.26–6.04).