This study sought to test 2 hypotheses: 1) fibroblast growth factor (FGF)-23 identifies patients with stable ischemic heart disease (SIHD) at high risk of cardiovascular events independent of clinical factors, renal function, and established cardiovascular biomarkers; and 2) FGF-23 identifies patients who derive greater clinical benefit from angiotensin-converting enzyme inhibitor therapy.
FGF-23 is an endocrine regulator of mineral metabolism and markedly elevated levels are associated with cardiovascular events in patients with chronic kidney disease. Data in patients with SIHD are more sparse.
FGF-23 levels were measured in 3,627 patients with SIHD randomly assigned to trandolapril or placebo within the PEACE (Prevention of Events With Angiotensin-Converting Enzyme) trial and followed up for a median of 5.1 years.
After adjustment for clinical risk predictors, left ventricular ejection fraction, markers of renal function, and established cardiovascular biomarkers, FGF-23 concentration was independently associated with an increased risk of cardiovascular death or heart failure among patients allocated to placebo (quartile 4 hazard ratio: 1.73; 95% confidence interval, 1.09 to 2.74; p = 0.02) and significantly improved metrics of discrimination. Furthermore, among patients in the top quartile of FGF-23 levels, trandolapril significantly reduced cardiovascular death or incident heart failure (hazard ratio: 0.45; 95% confidence interval: 0.28 to 0.72), whereas there was no clinical benefit in the remaining patients (hazard ratio: 1.07; 95% confidence interval: 0.75 to 1.52; p interaction = 0.0039). This interaction was independent of and additive to stratification based on renal function.
Elevated levels of FGF-23 are associated with cardiovascular death and incident heart failure in patients with SIHD and identify patients who derive significant clinical benefit from angiotensin-converting enzyme inhibitor therapy regardless of renal function.