Association of Circadian Rhythm Biomarkers and Ambulatory Blood Pressure Monitoring With Prognosis and Outcome in People With Acute Ischemic Stroke: A Case-Control Study.

Introduction This study examines the relationship between circadian biomarkers-specifically salivary cortisol and urinary melatonin-and ambulatory blood pressure monitoring (ABPM) patterns in patients with acute ischemic stroke (AIS). The goal was to determine whether these biomarkers could serve as prognostic indicators for stroke severity and recovery outcomes using the National Institutes of Health (NIH) Stroke Scale (NIHSS) and the modified Rankin scale (MRS) at discharge. Materials and methods This case-control study enrolled 75 AIS patients and 75 age- and sex-matched controls at a tertiary care center in northern India. Salivary cortisol and urinary melatonin were measured using enzyme-linked immunosorbent assay (ELISA) at a pre-specified time of the day. ABPM was performed over 24 hours. Stroke severity was assessed using the NIHSS, and functional outcomes were evaluated using the MRS. Statistical analyses included t-tests, Chi-squared tests, ANOVA, and Pearson correlation. Results In a comparative analysis involving 75 stroke patients and 75 controls, stroke patients demonstrated significantly lower urinary melatonin levels compared to controls, indicating a disruption in circadian rhythm. Although salivary cortisol levels were higher in stroke cases, the difference was not significant. ABPM data revealed a reduction in normal "dipper" patterns among stroke patients, with an increase in non-dipper and reverse-dipper profiles. Notably, lower melatonin levels were strongly associated with higher stroke severity and increased disability scores, while elevated cortisol levels correlated with greater stroke severity. Conclusions Alterations in circadian biomarkers, particularly reduced melatonin and modestly elevated cortisol, are linked to increased stroke severity and poorer functional outcomes. Additionally, abnormal ABPM patterns may reflect underlying autonomic dysregulation associated with stroke prognosis. These findings suggest that circadian biomarkers that were elaborated in this study could provide valuable insights for predicting stroke recovery and may offer new targets for therapeutic intervention.