Association of Fibroblast Growth Factor 23 and Cardiac Mechanics in the Cardiovascular Health Study

Key Points Evaluation of cardiac mechanics through two-dimensional speckle tracking echocardiography can identify early alterations in cardiac function. In a subset of the Cardiovascular Health Study, c-terminal and intact fibroblast growth factor 23 were not independently associated with cardiac mechanic indices. Background Elevated levels of fibroblast growth factor 23 (FGF23) are associated with left ventricular hypertrophy and heart failure in individuals with and without kidney disease. Prior studies investigated the association of FGF23 and structural cardiac changes using conventional echocardiography, which is limited in its ability to detect early cardiac dysfunction. We investigated the relationship between FGF23 levels and cardiac dynamics using two-dimensional speckle tracking echocardiography (2D-STE), a novel imaging modality. Methods This was a cross-sectional analysis of data from the Cardiovascular Health Study (CHS), an ongoing prospective, population-based cohort study. The study population included 506 participants from CHS with available c-terminal FGF23 (cFGF23) and intact FGF23 (iFGF23) measurements from 1996 to 1997 and 2D-STE images from 1994 to 1995. Forty-two percent of the study population had CKD, defined as an eGFR <60 ml/min per 1.73 m 2 , and the mean eGFR was 63 ml/min per 1.73 m 2 . The primary exposures were cFGF23 and iFGF23. The primary outcomes were six 2D-STE parameters performed at the 1994–1995 study visit. Linear regression models were used to examine the independent associations of FGF23 with six cardiac 2D-STE indices adjusting for demographics, cardiovascular risk factors, markers of kidney disease severity, and inflammation. Results cFGF23 levels were moderately correlated with iFGF23 levels in the CHS population. In fully adjusted models, cFGF23 was associated with left atrial dysfunction, but no other cardiac imaging parameter ( β estimate, −2.47; 95% confidence interval, −4.68 to −0.25; Table 2). iFGF23 was not associated with any of the six 2D-STE indices. Limitations include small sample size and noncurrent FGF23 measurements and 2D-STE imaging. Conclusions In a limited sample of individuals enrolled in the CHS with cFGF23 and iFGF23 measurements, we did not find consistent associations between FGF23 levels and 2D-STE parameters. Further investigations in a larger population with concurrent 2D-STE are needed to better understand the associations of FGF23 with early changes in cardiac mechanics.