2.2.1. Data Collection Procedure

A four-hour training session regarding data collection and infection control (e.g., wearing a mask, washing hands, and physical distancing) during the COVID-19 pandemic was provided for the interviewers (including medical students, doctors, and nurses) according to the guidelines provided by the World Health Organization (WHO) [29] and the Ministry of Health in Vietnam [30]. Then, patients were asked to sign an informed consent form before participating in a 30 min face-to-face survey at the bedside of each patient.

### 2.2.2. Assessment of Outcome

Stroke recurrence (SR) was identified by asking patients and their families whether the current hospitalization was the first or recurrent (including the number of times) stroke. Then, patients were regrouped into the first stroke vs. recurrent stroke to facilitate the analysis because of the limited sample size for the number of times of recurrent events.

#### 2.2.3. Assessment of Hypertension

A standard clinical manual aneroid sphygmomanometer was used for three-time measurements of systolic blood pressure (SBP) and diastolic blood pressure (DBP). The average SBP and DBP were computed. Additionally, participants' information about taking antihypertensive medication was obtained. Hypertension was identified as using any antihypertensive medication, SBP ≥ 140 mmHg, or DBP ≥ 90 mmHg [31,32].
