[Joint predictive effect of systolic blood pressure variability and sleep patterns on stroke]

Systolic blood pressure variability (SBPV) and unhealthy sleep patterns have been identified as risk factors for stroke. However, whether the coexistence of these two factors further increases the risk of stroke remains unclear. This study aims to investigate the joint predictive effect of these two factors on stroke.

A total of 219 376 participants from the UK Biobank were included in this study. SBPV was defined as the standard deviation of all systolic blood pressure measurements recorded within the previous 5 years, with at least three measurements ranging from 60 to 300 mmHg (1 mmHg=0.133 kPa). Participants were categorized into 4 quartile groups (Q1 to Q4) according to the quartiles of SBPV. At baseline, 5 sleep characteristics were collected through questionnaires: chronotype, sleep duration, insomnia, snoring, and daytime sleepiness. Participants received 1 point for each healthy sleep characteristic, with a maximum cumulative score of 5. Based on the total score, participants were classified into 3 groups: healthy sleep pattern group (4 to 5 points), intermediate sleep pattern group (2 to 3 points), and poor sleep pattern group (0 to 1 point). Cox proportional hazards models were used to evaluate the joint predictive effect of SBPV and sleep patterns on the risk of stroke.

After full adjustment for covariates, compared with participants with a healthy sleep pattern and SBPV in the first quartile (Q1), those with an intermediate sleep pattern and SBPV in the second, third, and fourth quartiles had a 22% (95% CI 1.05 to 1.41), 27% (95% CI 1.10 to 1.47), and 38% (95% CI 1.20 to 1.60) increased risk of stroke, respectively. Participants with a poor sleep pattern and SBPV in the third and fourth quartiles had a 47% (95% CI 1.17 to 1.84) and 80% (95% CI 1.47 to 2.21) higher risk of stroke, respectively. A multiplicative interaction between SBPV and sleep patterns was observed (P<0.05).

SBPV and poor sleep patterns have a multiplicative interactive predictive effect on stroke risk, highlighting the importance of simultaneously improving SBPV and sleep patterns.