Stroke remains a leading cause of mortality and long-term disability worldwide and contributes substantially to the global burden of non-communicable diseases [1,2]. In India, the burden of stroke has increased steadily due to demographic transition, longer life expectancy, and a rising prevalence of vascular risk factors, particularly hypertension and diabetes mellitus [3,4]. Hypertension is the most important modifiable risk factor for both ischemic and haemorrhagic stroke and influences stroke severity, early neurological deterioration, and mortality [5]. Blood pressure follows a circadian rhythm characterised by a physiological nocturnal decline. Based on the magnitude of this decline, individuals are classified as dippers, non-dippers, reverse dippers, or extreme dippers [6,7]. In acute stroke, circadian BP regulation may be disrupted due to autonomic dysfunction, neuroendocrine stress responses, and sleep disturbances [8]. Conventional ward BP measurements frequently fail to detect nocturnal hypertension. Ambulatory blood pressure monitoring offers a reliable assessment of 24-hour BP behaviour and superior prognostic value compared with clinic BP measurements [9,10].

This hospital-based cross-sectional observational study was conducted at R.G. Kar Medical College & Hospital, Kolkata, from June 2020 to May 2021. Patients aged ≥50 years with essential hypertension and radiologically confirmed ischemic or haemorrhagic stroke were included after written informed consent. Patients with secondary hypertension, significant arrhythmias, or inadequate ABPM recordings were excluded. A total of 91 patients were enrolled. Twenty-four-hour ABPM was performed prior to discharge using a validated device, with readings recorded every 30 minutes. Daytime was defined as 07:00–23:00 hours and night-time as 23:00–07:00 hours. Circadian BP patterns were classified based on nocturnal systolic BP reduction. Statistical analysis was performed using SPSS version 20.0. A p-value <0.05 was considered statistically significant.

The mean age of participants was 65.2 ± 11.7 years, with a slight male predominance (52%). Ischemic stroke accounted for 52.7% of cases, while 47.3% had haemorrhagic stroke. Abnormal circadian BP patterns were common. Non-dipping and reverse-dipping patterns were significantly more prevalent among haemorrhagic stroke patients. Mean night-time systolic BP was higher in haemorrhagic stroke. In-hospital mortality was significantly greater among patients with abnormal circadian BP patterns, particularly reverse dippers. Table 1: Baseline Demographic and Clinical Characteristics (n = 91) Variable Value Mean age (years) 65.2 ± 11.7 Male 47 (52%) Female 44 (48%) Ischemic stroke 48 (52.7%) Haemorrhagic stroke 43 (47.3%) Diabetes mellitus 35 (38.5%) Table 2: Distribution of Circadian BP Dipping Pattern by Stroke Type Dipping Pattern Ischemic Stroke (n=48) Haemorrhagic Stroke (n=43) Dipper 23 (47.9%) 14 (32.6%) Non-dipper 9 (18.8%) 14 (32.6%) Reverse dipper 2 (4.2%) 13 (30.2%) Extreme dipper 14 (29.2%) 2 (4.6%) Table 3: Mean Ambulatory Blood Pressure Values by Stroke Type Parameter (mmHg) Ischemic Stroke (Mean ± SD) Haemorrhagic Stroke (Mean ± SD) Day SBP 155.6 ± 8.4 151.1 ± 9.2 Night SBP 138.5 ± 11.3 143.9 ± 13.4 24-h Avg SBP 145.9 ± 7.7 145.9 ± 10.6 Day DBP 88.6 ± 4.5 84.8 ± 6.3 Night DBP 75.5 ± 5.8 79.5 ± 7.8 24-h Avg DBP 81.8 ± 4.2 82.5 ± 5.8 Table 4: Dipping Pattern and Outcome Dipping Pattern Discharged (%) Death (%) Dipper (n=37) 30 (81.1%) 7 (18.9%) Non-dipper (n=23) 14 (60.9%) 9 (39.1%) Reverse dipper (n=15) 10 (66.7%) 5 (33.3%) Extreme dipper (n=16) 11 (68.8%) 5 (31.3%) Table 5: Multiple Logistic Regression Analysis for Predictors of In-Hospital Mortality in Stroke Patients (n = 91) Variable Adjusted Odds Ratio (AOR) 95% Confidence Interval p-value Age ≥ 70 years 2.34 1.08 – 5.09 0.031 Male gender 1.21 0.56 – 2.64 0.629 Haemorrhagic stroke (vs ischemic) 2.89 1.29 – 6.46 0.010 Diabetes mellitus 2.67 1.18 – 6.02 0.018 Abnormal dipping pattern* 3.45 1.42 – 8.36 0.006 Reverse dipper pattern 4.12 1.46 – 11.63 0.007 Mean night-time SBP ≥ 140 mmHg 2.58 1.11 – 6.01 0.027 ARB + Diuretic therapy (vs ARB + CCB) 1.96 1.01 – 4.78 0.045 *Abnormal dipping pattern includes non-dipper, reverse dipper, and extreme dipper categories.

The present study demonstrates a high prevalence of abnormal circadian blood pressure patterns among hospitalised stroke patients. Non-dipping and reverse-dipping behaviour was particularly common in haemorrhagic stroke and was associated with adverse short-term outcomes. These findings are consistent with earlier studies showing that nocturnal BP dysregulation contributes to stroke severity and poor prognosis [11–15]. Elevated night-time systolic BP and reverse-dipping pattern emerged as strong predictors of in-hospital mortality, underscoring the clinical importance of nocturnal BP assessment.

Circadian blood pressure dysregulation is common among hospitalised patients with acute stroke. Non-dipping and reverse-dipping patterns are particularly prevalent in haemorrhagic stroke and are associated with poorer short-term outcomes. Twenty-four-hour ambulatory blood pressure monitoring offers clinically relevant insights into nocturnal hypertension and abnormal dipping patterns and should be considered an integral component of post-stroke blood pressure assessment and management. Ethics Approval and Consent to Participate The study was approved by the Institutional Ethics Committee of R.G. Kar Medical College & Hospital, Kolkata. Written informed consent was obtained from all participants or their legally authorised representatives. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Conflict of Interest The authors declare that they have no conflicts of interest.

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