The Correlation Between Fasting Blood Glucose and Stroke

Stroke has been linked to diabetes, but can analysis of fasting glucose provide greater insight into who is most at risk?

Stroke presents tremendous psychological and economic burdens on families and society. Thus, the prevention of stroke has now become a main priority for global public health. Research has demonstrated that diabetes can increase the likelihood of having a stroke. A cohort study with five hundred and ten thousand people determined that diabetes significantly increased the risk of ischemic stroke and haematencephalon. In addition, a prospective study determined that insulin resistance can predict primary stroke. However, these studies focus on diabetes status instead of ongoing glucose levels, as the study exposure limits generalization in research findings. Given that fasting blood glucose is the least affected by diet, fasting blood glucose levels are considered a better tool to measure blood glucose levels than random blood glucose levels. Thus, it is imperative to analyze the association between fasting blood glucose and the risk of stroke. 

Researchers collected blood samples the morning after an overnight fast and analyzed biochemical and clinical parameters on the same day. Fasting blood glucose was analyzed by an oxidase enzymatic method. High-density lipoprotein cholesterol, total cholesterol, and triglyceride levels were examined enzymatically utilizing commercial reagents with an automatic biochemistry analyzer. Friedewald formula determined low-density lipoprotein cholesterol levels. The primary outcome of the research was hospitalization or death caused by stroke collected by ICD-10 codes. If a participant suffers more than one stroke during the follow-up, the study only considers the first stroke. The study conducted a meta-analysis adding the current study findings with earlier observations on fasting blood glucose and stroke risk. PubMed, web of knowledge, medRxiv, and bioRxiv databases were utilized to find related articles. Two authors extracted information independently. When disagreements arose, a third author intervened. The study was carried out after the preferred reporting items for systemic review and meta-analyses guidelines. The study utilized a random effect method to determine the pooled risk estimation based on study heterogeneity. The begg and egger tests detected possible population bias.  

Participants with lower fasting blood glucose were less likely to suffer from obesity, hypertension, and hyperlipidemia than those with higher fasting blood glucose. The study determined that higher fasting blood glucose levels were significantly associated with an increased risk of total and ischemic stroke. The risk association was outstanding in women. Despite excluding the baseline of hypertension, hyperlipidemia, cardiovascular disease, cancer, and COPD, these correlations persisted in analyses of women. When examining stroke subgroups, there is no evidence that fasting blood glucose is correlated with non-ischemic stroke, but the correlation with ischemic stroke remains. Compared to males, females with diabetes are at a higher risk of stroke. The sex specificity of the severity of diabetes-associated cardiovascular disease was previously believed to be caused by differences between males and females in treatment and chronic disease management. However, despite gradual equality of treatment, the likelihood of severe cardiovascular disease in postmenopausal women is still more remarkable.  

The strength of this study consists of the measurement of plasma fasting blood glucose and the complete follow-up. Reports show that HbA1c played a significant role in differentiating people with high cardiovascular risk from those without diabetes. Lack of HbA1c measurements and levels of estradiol and testosterone in the study subjects not being measured presented limitations in the study. To conclude, the study demonstrated that higher fasting blood glucose levels were correlated with an increased stroke in the overall population, and meta-analysis corroborated this finding. Furthermore, it is seen that the correlation is more prominent in females than in males. Therefore, normal fasting blood glucose levels and affordable measurements could be utilized to identify individuals with a higher risk of stroke in the future.  

Practice Pearls: 

• Stroke is a prevalent cause of human disease and death and causes millions of disabilities adjusted life years annually. 
• Research has demonstrated that diabetes can increase the likelihood of having a stroke. 
• Higher fasting blood glucose levels are correlated with an increased risk for stroke in the overall population 

Zhang, Ya et al. “Association between fasting blood glucose levels and stroke events: a large-scale community-based cohort study from China.” BMJ open vol. 11,8 e050234. August 18 2021,  

Yao, Tao et al. “Association between fasting blood glucose and outcomes and mortality in acute ischaemic stroke patients with diabetes mellitus: a retrospective observational study in Wuhan, China.” BMJ open vol. 10,6 e037291. June 23, 2020. 

Emmanuella Louissaint, PharmD Candidate, LECOM College of Pharmacy