Elevated Interleukin-6 Levels Are Associated With an Increased Risk of QTc Interval Prolongation in a Large Cohort of US Veterans.

BACKGROUND: Although accumulating data indicate that IL-6 (interleukin-6) can promote heart rate-corrected QT interval (QTc) prolongation via direct and indirect effects on cardiac electrophysiology, current evidence comes from basic investigations and small clinical studies only. Therefore, IL-6 is still largely ignored in the clinical management of long-QT syndrome and related arrhythmias. The aim of this study was to estimate the risk of QTc prolongation associated with elevated IL-6 levels in a large population of unselected subjects. METHODS AND RESULTS: An observational study using the Veterans Affairs Informatics and Computing Infrastructure was performed. Participants were US veterans who had an ECG and were tested for IL-6. Descriptive statistics and univariate and multivariate regression analyses were performed to study the relationship between IL-6 and QTc prolongation risk. Study population comprised 1085 individuals, 306 showing normal (<5 pg/mL), 376 moderately high (5-25 pg/mL), and 403 high (>25 pg/mL) IL-6 levels. Subjects with elevated IL-6 showed a concentration-dependent increase in the prevalence of QTc prolongation, and those presenting with QTc prolongation exhibited higher circulating IL-6 levels. Stepwise multivariate regression analyses demonstrated that increased IL-6 level was significantly associated with a risk of QTc prolongation up to 2 times the odds of the reference category of QTc (e.g. QTc >470 ms men/480 ms women ms: odds ratio, 2.28 [95% CI, 1.12-4.50] for IL-6 >25 pg/mL) regardless of the underlying cause. Specifically, the mean QTc increase observed in the presence of elevated IL-6 was quantitatively comparable (IL-6 >25 pg/mL:+6.7 ms) to that of major recognized QT-prolonging risk factors, such as hypokalemia and history of myocardial infarction. CONCLUSIONS: Our data provide evidence that a high circulating IL-6 level is a robust risk factor for QTc prolongation in a large cohort of US veterans, supporting a potentially important arrhythmogenic role for this cytokine in the general population.

Ultrasound measurement of rectus femoris muscle thickness as a quick screening test for sarcopenia assessment.

INTRODUCTION: Sarcopenia is a geriatric syndrome related to loss of muscle mass and function, leading to disability, frailty and higher mortality. According to European Working Group on Sarcopenia in Older People (EWGSOP) the diagnosis of sarcopenia requires the assessment of muscle mass, muscle force and function, that is time-consuming and not easily at hand in everyday clinical practice. We propose the B-mode ultrasound measurement of muscle thickness as a quick screening test to assess the presence of sarcopenia. METHODS: A cross-sectional study was realized, 119 patients (average age 82 years, 50.4% females) from the Department of Internal Medicine of the University Hospital of Siena (Italy) were enrolled. The diagnosis of sarcopenia was assessed according to EWGSOP criteria. Rectus femoris muscle (RFM) thickness (in cm) was measured by ultrasound B-mode scanning. Sensibility and specificity of the test was evaluated and Receiver Operating Analysis (ROC) was performed to assess the accuracy of the test. RESULTS: Average RFM thickness was 0.78 ± 0.26, significantly lower in sarcopenic patients (0.55 ± 0.2 vs. 0.9 ± 0.3; Mann-Whitney; p < 0.001) and females (0.7 ± 0.3 vs 0.86 ± 0.3; Mann-Whitney; p < 0.001). The cut-off point of 0.7 cm for females and 0.9 cm for males was established as a threshold to assess the presence of sarcopenia by ultrasound. Sensibility of ultrasound measurement of RFM thickness was 100%, specificity 64%, positive predictive value (PPV) 64.3% and negative predictive value (NPV) 100%. ROC analysis was performed in order to quantify how accurately RFM thickness can discriminate between sarcopenia and non-sarcopenia state. AUC for all patients was 0.9 and after a comparative analysis for gender higher values for males (0.94 vs. 0.92) were observed. CONCLUSION: We suggest a screening test for sarcopenia based on the ultrasound measurement of RFM thickness, as a not invasive and easy to perform method even in elderly patients with functional or cognitive impairment.