Salivary cortisol, a biological marker of stress, is positively associated with 24-hour systolic blood pressure in patients with acute ischaemic stroke

Abstract

Background/aim: The cause of elevated blood pressure (BP) in acute stroke is unknown. Stress is often suggested as a main contributing factor. We aimed to investigate the relationship between BP and stress in patients with acute stroke.

Methods: 58 patients with clinical symptoms of stroke were recruited prospectively after exclusion of haemorrhage by CT scan within 14 h and 15 min (mean) after symptom onset (range 2 h and 45 min-23 h and 40 min). The mean age of the patients was 66 years (range 39-86 years), and the mean National Institute of Health Stroke Scale score was 7 (range 1-26). BP and pulse rate were recorded by non-invasive automatic monitoring hourly for 24 h. Stress was evaluated by testing the level of salivary cortisol. Four samples of saliva were obtained at inclusion, on the evening of the inclusion day (20.00-22.00 h), on the morning of the next day (7.00-9.00 h) and on the afternoon of the inclusion day/next day (15.00-17.00 h) within 24 h after inclusion in the study. Logarithmic transformation was done for cortisol levels.

Results: The 24-hour mean cortisol level (geometric mean 13.6 nmol/l) was related to 24-hour mean systolic BP [SBP; r = 0.36, p = 0.01, multivariate p = 0.02], mean night-time (22.00-6.00 h) SBP (r = 0.43, p = 0.001, multivariate p < 0.005) and mean night-time diastolic BP (r = 0.31, p = 0.02, multivariate p = 0.02). Cortisol levels at inclusion (r = 0.31, p = 0.02, multivariate p = 0.05 for 24-hour SBP) and in the evening were also statistically significantly related to the above BP variables. The morning cortisol (r = 0.28, p = 0.04, multivariate p = 0.04) was related to night-time SBP.

Conclusions: Salivary cortisol was positively correlated with 24-hour SBP and night-time BP, suggesting that stress is a contributing factor for high BP in acute stroke.