High sensitivity quantikine kit

All participants underwent clinical and laboratory evaluations at baseline to identify the presence and severity of cardiovascular risk factors as well as subclinical and clinical cardiovascular disease. The diagnosis of prevalent cardiovascular diseases at baseline and during follow up was centrally adjudicated.^{16 (link)} The definitions of hypertension, diabetes, dyslipidemia, and hyperuricemia used in this study are provided in the Supplemental Methods. Collection of blood samples at baseline was performed via venipuncture after a 12-hour fast. Further details on sample processing are available in the Supplemental Methods and previous publications.^{16 (link)–18 (link)} Plasma IL-6 levels were measured by enzyme-linked immunosorbent assay (ELISA, High Sensitivity Quantikine kit, R&D Systems, Minneapolis, MN, USA). The plasma samples used for IL-6 ELISA were prepared using ethylenediaminetetraacetic acid (EDTA) and were run in duplicates. The detectable limit was 0.10 pg/mL, the intra-assay coefficient of variability was 6.3% and the inter-assay coefficient of variability was 7%.^{19 (link),20 (link)}