2.1 Study design
An institution based prospective, cross-sectional study was conducted at Tikur Anbessa Specialized Hospital (TASH) between July and December, 2016.
2.2 Study Setting
TASH is located in the capital Addis Ababa and it is the largest and the first tertiary level referral university teaching hospital with an estimated bed capacity over 700.It has an emergency unit, intensive care unit, neurology ward, clinical laboratory, and radiology department with a CT and MRI scan providing an integrated clinical service by highly trained radiologists, neurologists and emergency care physicians for the entire nation.
2.3 Study population
The study population was all patients presenting to the emergency department with neurologic deficits suggestive of acute stroke and who fulfilled the inclusion criteria of age greater than 14 years, presentation within 72 hours of symptom onset, and confirmation of stroke diagnosis using emergency brain Computerize tomography scan. A non-fasting capillary blood sample was used to estimate the admission blood glucose (ABG) using a calibrated glucometer. Patients with Transient ischemic attack (TIA), trauma related cerebral hemorrhage, prior neurologic deficit, unknown duration from symptom onset or CT scan, and who declined to give consent were excluded.
2.4 Sample size and sampling technique
The sample size was calculated using the single population proportion formula n=Z 2*pq/d2 = 164 with estimated population proportion of 30% , α= 5% and d= 5%. During the study period, we performed a systematic enrollment of all first ever acute stroke patients consecutively who met the inclusion criteria and consented to participate in the study.
2.5 Data collection
The socio-demographic and clinical data were collected using structured questionnaire which was pre-tested on 8 acute stroke patients in a pilot study with complete response rate. We tried to avoid selection bias by randomly selecting the study population from the target population. At admission stroke severity was assessed by National Institute of Health Stroke Scale (NIHSS), well validated and commonly used measure of acute stroke-related neurologic deficit. NIHSS score was categorized into two: mild stroke (NIHSS score ≤ 14) and severe stroke (NIHSS score >14) . In all patients, ABG was documented and hyperglycemia was defined as ABG level ≥140 mg/dl and normoglycemia as ABG <140mg/dl . Known DM was diagnosed if patient was diagnosed with diabetes or taking antidiabetics drugs before stroke onset. If the ABG was >200 mg/dl and a repeat test after 8 hour of fasting showed ≥126 mg/dl, patients were defined as newly diagnosed DM.
The modified Rankin scale (mRS) was used to describe the functional outcome at 30-day after stroke onset which may coincide with the hospital discharge and for those who were discharged earlier we followed them by telephone using standardized interview protocol. mRS is a six point scores which focuses on global disability including instrumental and basic activity of daily living (ADL).The mRS score was categorized into; favorable outcome (independence in ADL, scores range 0-2), and poor outcome (dependence in ADL, scores range 3-5). mRS score of 6 means dead and documented as case fatality .
2.7 Statistical analysis
The statistical analysis was performed using SPSS version 20.0 computer program. Descriptive statistics were summarized using the frequency and proportion table for categorical data with mean (standard deviation) or median (interquartile range) for continuous data. Dichotomous categorical variables were compared using the Pearson’s Chi square test. Those factors that showed significant association were added for multivariate analysis. In multivariate analysis, age and baseline NIHSS score were added as covariates because they were accepted as independent predictors of stroke outcomes (15). Also interactions between hyperglycemia and history of diabetes were tested. A binary logistic regression model was used with adjustment for possible confounders to calculate odds ratios with 95% confidence interval (CI). A p value of < 0.05 was considered statistically significant.
2.8 Ethics approval and consent to participate
Ethics approval was obtained from the Institutional Review Board (IRB) of College of Health Science in Addis Ababa University. All participants were asked to give written informed consent. For patients with depressed consciousness or severe aphasia, consent was obtained from their care takers. For participants aged 14-18 years an assent form was obtained from the parents or legal guardians. Confidentiality and anonymity of all patient data were kept throughout the study. The study was performed in accordance with the Declaration of Helsinki.