Comment

Stroke epidemiology in the developing world

There are limited data from Africa on the burden and associations between pre-diabetes (pre-DM), diabetes mellitus (DM) and stroke occurrence in a region experiencing a profound rise in stroke burden.

To characterize the associations between stroke and dysglycemic status among West Africans.

The Stroke Investigative Research and Educational Network (SIREN) is a multicenter, case-control study involving 15 sites in Ghana and Nigeria. Cases include adults aged ≥18 years with clinical and radiological evidence of an acute stroke. Controls were age-and-gender matched stroke-free adults. Detailed evaluations for vascular factors were performed. Pre-diabetes was defined as HBA1c of 5.7%-6.4% or Fasting blood glucose (FBG) 5.6-7.0 mmol/L and DM as HBA1c >6.5% or FBG>7.0 mmol/L. We used conditional logistic regression to estimate adjusted odds ratios (aOR) with 95% Confidence Interval.

Among 2,935 stroke cases the mean age was 60.0 ± 14.2 years with 55.2% being males. By glycemic status, 931 (31.7%) were euglycemic, 633 (21.6%) had Pre-diabetes and 1371 (46.7%) had DM. Of the age- and sex-matched stroke-free controls 69.2% were euglycemic, 13.3% had pre-DM and 17.5% had DM. Pre-DM [aOR (95% CI): 3.68(2.61-5.21)] and DM [4.29 (3.19-5.74)] were independently associated with stroke. The aOR of Pre-DM for ischemic stroke 3.06 (2.01–4.64)] was lower than 4.82 (3.37-6.89) for DM. However, the aOR of Pre-DM for hemorrhagic stroke 6.81 (95% CI: 3.29 – 14.08)] was higher than 3.36 (1.94–5.86) for DM. Furthermore, the aOR of pre-DM for ischemic stroke subtypes were 9.64 (1.30-71.57) for cardio-embolic stroke, 3.64 (1.80–7.34) for small-vessel occlusive disease and 4.63 (0.80-26.65) for large-vessel disease.

Pre-DM is strongly and independently associated with stroke in Africans. Improving glycemic control through screening, healthy lifestyle and pharmacotherapy at a population level may be strategic in reducing the rising burden of stroke in Africa.

Objectives: While few studies investigated the incidence of stroke in Iran, no Iranian cohort has estimated the standardized-incidence rate and early fatality of first-ever-stroke subtypes along with associated factors. Methods: Golestan Cohort Study is a prospective study launched in northeastern Iran in 2004, including 50,045 individuals aged 40-75 at baseline. Age-standardized incidence rate of first-ever-stroke was calculated per 100,000 person-years, according to World Standard Population. The 28-day case fatality was calculated by dividing the number of fatal first-ever-stroke during the first 28 days by total events. Cox proportional hazard models were conducted to assess incidence and fatality risk factors. We used Population Attributable Fractions to estimate the incidence and early fatality proportions reduced by ideal risk factor control. Results: 1,135 first-ever-strokes were observed during 8.6 (median) years follow-up. First-ever-stroke standardized incidence rate was estimated 185.2 (95% CI: 173.2-197.2) per 100,000 person-years. The 28-day case fatality was 44.1% (95% CI: 40.4-48.2). Hypertension and pre-stroke physical activity were the strongest risk factors associated with first-ever-stroke incidence (Hazard ratio: 2.83; 2.47-3.23) and 28-day case fatality (Hazard ratio: 0.59; 0.44-0.78), respectively. Remarkably, opium consumption was strongly associated with hemorrhagic stroke incidence (Hazard ratio: 1.52; 1.04-2.23) and ischemic stroke fatality (Hazard ratio: 1.44; 1.01-2.09). Overall, modifiable risk factors contributed to 83% and 61% of first-ever-stroke incidence and early fatality, respectively. Conclusion: Efficient risk factor control can considerably reduce stroke occurrence and fatality in our study. Establishing awareness campaigns and 24-hour stroke units seem necessary for improving the stroke management in this area.

To investigate prospective key genes and pathways associated with the pathogenesis and prognosis of stroke types along with subtypes. Human genes using genome assembly build 38 patch release 13 with known gene symbols through NCBI gene database (https://www.ncbi.nlm.nih.gov/gene) were fetched. PubMed advanced queries were constructed using stroke-related keywords and associations were calculated using Normalized pointwise mutual information (nPMI) between each gene symbol and queries. Genes related with stroke risk within their types and subtypes were investigated in order to discover genetic markers to predict individuals who are at the risk of developing stroke with their subtypes. A total of 2,785 (9.4%) genes were found to be linked to the risk of stroke. Based on stroke types, 1,287 (46.2%) and 376 (13.5%) genes were found to be related with ischemic stroke (IS) and hemorrhagic stroke (HS) respectively. Further stratification of IS based on TOAST classification, 86 (6.6%) genes were confined to Large artery atherosclerosis; 131 (10.1%) and 130 (10%) genes were related with the risk of small vessel disease and Cardioembolism subtypes of IS. Evidences reported through published meta-analysis and GWAS studies suggested for the association of nine highly associated genes and therefore, we concluded a prognostic panel of nine genes comprising of CYP4A11, ALOX5P, NOTCH, NINJ2, FGB, MTHFR, PDE4D, HDAC9, and ZHFX3 can be treated as a diagnostic marker to predict individuals who are at the risk of developing stroke. Validation of these nine prognostic markers are further required by conducting case-control studies embedded with large sample size.

This review focuses on the need of mobile health (or m-Health) based devices for remote diagnosis of patients suffering from upper limb or upper extremity (UE) paresis due to stroke in developing or low and middle-income (LMI) countries. More than 70% of stroke survivors suffer from UE paresis. UE paresis limits the ability of an individual to perform activities of daily living (ADL), as well as social and recreational activities and hence needs sufficient care. Therefore, this paper considers advanced diagnostic procedures of post stroke upper limb paresis. To begin with, a detailed survey of death due to stroke, post-stroke disability and scarcity of rehabilitation centers in context of developing countries are presented briefly. It has been found that in developing countries, especially in the rural areas, patients suffering from disabilities due to stroke do not receive appropriate on-time treatment due to developmental and financial barriers. Conventional rehabilitation management systems fail to cater required rehabilitation services thereby arousing the need for evolution of wearable m-Health devices for uninterrupted monitoring of patients with UE paresis. Some lacunae in existing rehabilitation management systems and proposal for alleviating these gaps are presented in this paper. Continuous monitoring of affected body part can lead to timely diagnosis and faster recovery. Therefore, this paper attempts to establish the need for m-Health based device for UE monitoring to facilitate a better rehabilitation process for the stroke survivors.

Recent developments of low-cost, compact acoustic sensors, advanced signal processing tools and powerful computational resources allow researchers design new scoring systems for acoustic detection of arterial stenoses. In this study, numerical simulations of blood flow inside stenosed arteries are performed to understand the effect of stenosis severity and eccentricity on the turbulence induced wall pressure fluctuations and the generated sound.

Axisymmetric and eccentric elliptic stenoses of five different severities are generated inside a 6.4 mm diameter femoral artery model. Large eddy simulations of pulsatile, non-Newtonian blood flow are performed using the open source software OpenFOAM.

Post-stenotic turbulence activity is found to be almost zero for 50 and 60% severities. For severities of 75% and more, turbulent kinetic energy rises significantly with increasing severity. The location of the highest turbulence activity on the vessel wall from the stenosis exit decreases with increasing severity. The maximum level of turbulent kinetic energy seen in 95% severity models is about 9 and 31 times higher than that of 87% and 75% models, respectively. Spectrum of wall pressure fluctuations show that 50 and 60% axisymmetric models are almost silent. The spectrum starts to get richer with 75% severity, and the fluctuation intensity increases with severity. Compared to the axisymmetric models, more activity is observed in the 0–150 Hz band for the 50 and 60% eccentric models. Axial extent of the acoustically active region is also longer in them. Converting wall pressure data into sound revealed that murmurs that can be considered as signs of vascular stenosis are obtained for models with 75% and higher severity.

Sound patterns generated from simulation results are similar to the typical sounds obtained by Doppler ultrasonography, and present distinct characters. Together with a sensor technology that can measure these sounds from within the stenosed artery, they can be processed and used for the purpose of non-invasive diagnosis. Computational fluid dynamics studies that simulate large number of cases with different stenosis severities and morphologies will play a critical role in developing the necessary sound databases, which can be used to train new diagnostic devices.

Expert consensus guidelines recommend optimizing global risk factor control in diabetic stroke survivors to improve outcomes. Since relatively little is known about the adequacy of risk factor control among diabetic stroke survivors in sub-Saharan Africa, we sought to assess control rates of key traditional risk factors among Ghanaian stroke survivors with diabetes. A secondary objective was to assess the burden of undiagnosed dysglycemic states among stroke survivors without a prior diagnosis of diabetes mellitus (DM)

Cross-sectional study of outpatient stroke survivors consecutively enrolled in a stroke registry at a tertiary medical center in Ghana between January 2018 and March 2020. We collected baseline demographic and clinical details including blood pressure, lipid panel, fasting blood glucose results, medications prescribed for secondary prevention, and stroke type information. BP control target was set at <130/80 mmHg, LDL-cholesterol <2.6 mmol/l and Fasting blood glucose (FBG) <7.0 mmol/l. Factors associated with poor control of vascular risk factors were assessed using multivariate logistic regression models.

Of 1101 stroke survivors enrolled into the registry, 279 (25.3%) had a comorbid diagnosis of DM. Mean (±SD) age among the diabetic vs. non-diabetic stroke patients was 61.4 ± 12.0 years vs. 57.6 ± 14.6 years (p < 0.0001). Among the diabetic stroke patients, 61.7% had LDL-cholesterol <2.6 mmol/L, 8.2% had BP <130/80 mm Hg and 28.6% had FBG <7.0 mmol/L. Significant predictors of poor control of BP were younger age, having co-morbid DM and number of antihypertensive medication classes while poor LDL-cholesterol was associated with longer duration of stroke diagnosis. Among those without a prior diagnosis of DM, FBG analysis of 540 subjects with available data showed that 21.7% had FBG <5.7 mmol/L, 39.0% had impaired fasting blood glucose and 39.3% had FBG in the diabetes mellitus range. Patients who were older, female, or experienced an ischemic stroke trended towards being more likely to have undiagnosed DM.

Among Ghanaian diabetic stroke survivors, blood pressure and blood glucose, are especially poorly controlled. There is also a high burden of undiagnosed pre-diabetes and DM among stroke survivors substantially heightening their risk for further adverse CVD outcomes.