FGF23 and chronic kidney disease: One group of risk factors are uremic toxins, defined as substances elevated in CKD, associated with disease in patients, and toxicity in vitro.[6] Uremic toxins include gut‐derived toxins such as indoxyl sulfate, but also CKD‐MBD toxins such as elevated phosphate, parathyroid hormone (PTH), and fibroblast growth factor‐23 (FGF23) that have been linked with arterial calcification, left ventricular hypertrophy (LVH), and myocardial fibrosis in animal models and patients with CKD.[7, 8, 9, 10]