Effect of glycaemic excursions on QT interval in diabetes patients
Nadeem, Asma
Nadeem, Asma
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Publication Date
2023-09-19
Type
Thesis
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Abstract
Glucose excursions in Diabetes Mellitus patients are associated with increased risk of cardiac morbidity and mortality (Kaul, Tarr, Ahmad, Kohner, & Chibber, 2013). With the evidence from several clinical trials, it is understood that the hyperglycaemia contributes to increased cardiovascular disease (CVD) risk, particularly cardiac arrythmia due to prolongation of QT interval in Electrocardiogram (ECG). On the other hand, there is considerable evidence from meta-analysis of clinical trials that suggest a strong association of hypoglycaemia with prolongation of QT and CVD outcomes. There are various other factors that are also related to QT-prolongation. The aim of this research is to synthesise available literature to analyse and establish a clear understanding of effect of glucose excursions on QT interval which consequently increases CVD risk. Objective of the thesis is to study the relationship of glucose excursions with QT-interval in electrocardiogram to understand the extent of the effect of hyper- and hypoglycaemia on QT-interval. A systematic approach for literature review and evidence synthesis has been employed to collect available clinical evidence and to analyse the reported outcomes. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, three databases, PubMed, Cochrane and Embase were searched for evidence published between 2000 and 2022. The search resulted in a total of 3039 records reporting clinical trials, observational studies, case reports and meta-analysis. After removing the duplicates (n=440), 2599 articles were selected for title and abstract review followed 250 full paper reviews for eligibility of inclusion. A total of 77 articles were selected for review and 43 studies were selected for meta-analysis based on data availability. The meta-analysis is performed on all data, and sub-groups based on sub-types of diabetes and healthy population. These 43 studies were further grouped as 17 experimental studies, 18 observational studies and 8 case reports. A pooled analysis of experimental studies showed a positive effect in both hypoglycaemia (Cohen’s d = 1.14; 95% CI 1.01-1.26) and hyperglycaemia (Cohen’s d = 0.5; 95% CI 0.38-0.63) compared to normal glucose levels. Hypoglycaemia has a strong effect compared to hyperglycaemia in both healthy volunteers and diabetes patients. QTc was also prolonged in all case reports (>460 ms). Similarly, results show that QTc is prolonged in hypoglycaemia, reported in observational studies (Cohen’s d = 0.58; 95% CI 0.01-1.18). It is observed that diabetic population has more QTc prolonged cases than healthy population. QTc is more prolonged in hypoglycaemic population (34.23 ms; 95% CI 30.71-37.75 ms) than hyperglycaemic population (11.04 ms; 95% CI 8.30-13.78 ms).
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Publisher
NUI Galway