Study Design and Population
This cohort study was conducted in a tertiary public teaching hospital at Muhimbili University of Health and Allied Science Academic Medical Center (MAMC), in Dar es Salaam, Tanzania. MAMC offers super-specialized medical care for all specialties and receives referrals from public and private hospitals from all over the country as well as walk in patients. We consecutively enrolled consenting participants who were admitted at MAMC with a clinical diagnosis of first ever stroke based on the World Health Organization (WHO) definition for stroke (11). Participants or their next of kin were required to provide written informed consent and had to be ≥ 18 years at the time of consent prior to enrollment. Study participants were prospectively enrolled between June 2018 to January 2019 and each participant was followed up to a total of 30 days from enrollment into the study.
Data collection
An interviewer based structured questionnaire was administered to all study participants or their caregivers if the participant was unable to communicate. The questionnaire captured sociodemographic information, smoking and alcohol consumption, history of hypertension, diabetes mellitus, cardiac disease, and HIV infection. Other information collected included: use of medications for hypertension, diabetes, HIV, illicit drug use and use of hormonal contraception for females. The date of onset of stroke symptoms and date of arrival to the hospital was also recorded. Cigarette smoking and alcohol consumption was categorized as ever smoked and taken alcohol in life or never smoked or taken alcohol respectively. Current smokers/current alcohol consumers were defined as cigarette smoking/alcohol consumption within the last 12 months respectively.
All participants had their waist and hip circumference measured using a tape measure and recorded in centimeters. All participants were examined for radial pulse rate and rhythm, to detect for irregular pulses, and blood pressure (BP) measurements on the normal forearm and arm respectively. BP measurements was done using a standard digital BP machine AD Medical Inc. Three BP readings were collected spaced 5 minutes apart and an average BP was computed. Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mmHg or diastolic blood pressure (DBP) ≥ 90 mmHg. Precordial and neck carotid auscultation was performed using the stethoscope bell for mid-diastolic murmurs and carotid bruits respectively. Examination findings were recorded in a pre-specified case report forms.
We aseptically collected 15mls of venous blood from each study participant: 5mls were analyzed for random total cholesterol, triglycerides, low density and high density lipoproteins using BIO- SYSTEMS machine, 5 mls were analyzed for complete blood count using HEMOLYZER 3 PRO machine and 5mls were analyzed for sickling test. Sickling test was performed using sodium metabisulphite and slides were viewed using Olympus microscope.
Capillary fingertip blood samples were collected from each participant to check for random blood glucose (RBG) levels and HIV rapid testing using a glucometer GLUCOPLUS™ and SD Bioline respectively. A fasting blood glucose (FBG) sample was collected in the following morning for participants with (RBG) levels of ≥ 11.1 mmol/l. DM diagnosis was defined as a RBG reading of ≥ 11.1 mmol/l, and or a FBG reading of ≥ 7 mmol/l. For participants who were reactive to SD Bioline, samples were tested using Unigold Biotech.
Non-contrast brain computer tomography (NCCT) using GE Healthcare Optima or Magnetic Resonance Imaging (MRI) GE SIGNA CREATOR were performed to study participants at the MAMC radiology department and interpreted by a trained radiologist. Brain infarction was defined as a hypo dense area occupying a vascular territory and brain hemorrhage as a hyper dense lesion by NCCT. Infarction on MRI was defined as an area of iso/hypointensity on T1, high signal intensity on T2/Flair with high diffusion weighted imaging and low Apparent Diffusion Coefficient values and hemorrhage was defined as an area of variable T1/T2 signal based on age of stroke and a dark signal area in T2 sequence.
Transthoracic echocardiography (ECHO) using GE Medical Systems was performed by a trained cardiologist and interpretation was based on European Society of Cardiology/American Society of Echocardiography (12). Left ventricular muscle mass was assessed using a four chamber view at the end of diastole, a septal thickness > 10 mm and > 11 mm was considered LVH for females and males respectively. Mitral Stenosis (MS) was defined as mitral valve area of > 1.5 cm2 in short axis view and mean pressure gradient of < 5 mmHg using continuous Wave Doppler. A 12 lead electrocardiography (ECG) using Bionet machine was performed on the study participants to look for evidence of Atrial fibrillation.
Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS) (11). A score of 1–4 was defined as minor stroke, 5–15 moderate stroke, 15–20 moderate to severe and 21–42 severe stroke. Stroke outcomes was defined as death or survival with disabilities using the Modified Rankin Scale (MRS) (11) at 24 hours, 72 hours, 7 days, 14 days and at 30 days from admission.