Interleukin-6 and suPAR are associated with diastolic function in type 1 diabetes: The Thousand & 1 Study

Abstract Background Heart failure (HF) is a common complication in individuals with type 1 diabetes (T1D). Inflammation is an important contributor to the pathogenesis and progression of both T1D and HF – especially HF with preserved ejection fraction (HFpEF). Diastolic dysfunction is a hallmark of HFpEF. Despite this, the association between diastolic function and inflammatory biomarkers is not well-known in individuals with T1D. Methods The Thousand & 1 study of individuals with T1D without known heart disease was studied. Diastolic parameters, including E/e’, was obtained by echocardiography and associated with Interleukin-6 (IL-6), soluble urokinase-type plasminogen activator receptor (suPAR) and high-sensitivity C-reactive protein (hsCRP). These inflammatory biomarkers were analysed as continuous variables and dichotomized in above/below 3 pg/mL (IL-6), 4 ng/mL (suPAR), and 4 mg/L (hsCRP). In multivariable regression analysis, adjustments were made for age, gender, body mass index, duration of diabetes, HbA1c, systolic blood pressure, left ventricular ejection fraction, glomerular filtration rate, albuminuria status, use of statins, tobacco use and physical activity levels. In an additional analyse, we also adjusted for N-terminal pro–B-type natriuretic peptide (NT-proBNP). Results We included 1,014 individuals (52% male, mean age 50±15). IL-6 was elevated in 207 individuals, suPAR in 182 individuals, and hsCRP in 863 individuals. Mean E/e’ was 7.6 and mean left ventricular ejection fraction was 58±5%. In fully adjusted models, inflammatory biomarkers were significantly associated with diastolic function. Thus, individuals with IL-6 > 3 pg/mL had 0.6 (95% confidence intervals: 0.2 to 1.0), P=0.001) higher E/e’ compared to individuals with IL-6 < 3 pg/mL. For every doubling of suPAR levels, E/e’ increased by 0.5 (0.2 to 0.9, P=0.003). For every doubling of hsCRP levels, E/e’ increased by 0.1 (0.02 to 0.2, P=0.022). Individuals with elevated levels of all three biomarkers had 1.9 (0.5 to 3.2, P=0.006) higher E/e’ compared to low levels of all three biomarkers. Including NTproBNP to the model did essentially not change the estimates. Conclusions Firstly, in T1D, elevated levels of IL-6, suPAR and hsCRP are associated with diastolic function assessed by E/e’, independent of traditional risk factors including NT-proBNP. Secondly, IL-6, suPAR and hsCRP may contain information about diastolic function in T1D which is not detected by NT-proBNP.Figure 1Figure 2