Background and objectives: Elevated fibroblast growth factor-23 (FGF23) has been consistently associated with heart failure, particularly heart failure with preserved ejection fraction, among patients with CKD and in the general population. FGF23 may directly induce cardiac remodeling and heart failure. However, biases affecting observational studies impede robust causal inferences. Mendelian randomization leverages genetic determinants of a risk factor to examine causality. We performed a two-sample Mendelian randomization to assess causal associations between FGF23 and heart failure.
Design, setting, participants, & measurements: Genetic instruments were genome-wide significant genetic variants associated with FGF23, including variants near PIP5K1B, RGS14, LINC01229, and CYP24A1. We analyzed data from the Heart Failure Molecular Epidemiology for Therapeutic Targets and BioVU biobanks to examine associations of the four variants with overall heart failure, heart failure with preserved ejection fraction, and heart failure with reduced and mid-range ejection fraction. We developed an eGFR polygenic risk score using summary statistics from the Chronic Kidney Disease Genetics Consortium (CKDGen) genome-wide association study of eGFR in >1 million individuals and performed stratified analyses across eGFR polygenic risk score strata.
Results: Genetically determined FGF23 was not associated with overall heart failure in the Heart Failure Molecular Epidemiology for Therapeutic Targets consortium (odds ratio, 1.13; 95% confidence interval, 0.89 to 1.42 per unit higher genetically predicted log FGF23) and the full BioVU sample (odds ratio, 1.32; 95% confidence interval, 0.95 to 1.84). In stratified analyses in BioVU, higher FGF23 was associated with overall heart failure (odds ratio, 3.09; 95% confidence interval, 1.38 to 6.91) among individuals with low eGFR-polygenic risk score (<1 SD below the mean), but not those with high eGFR-polygenic risk score (P interaction = 0.02). Higher FGF23 was also associated with heart failure with preserved ejection fraction among all BioVU participants (odds ratio, 1.47; 95% confidence interval, 1.01 to 2.14) and individuals with low eGFR-polygenic risk score (odds ratio, 7.20; 95% confidence interval, 2.80 to 18.49), but not those high eGFR-polygenic risk score (P interaction = 2.25 × 10-4). No significant associations were observed with heart failure with reduced and midrange ejection fraction.
Conclusion: We found no association between genetically predicted FGF23 and heart failure in the Heart Failure Molecular Epidemiology for Therapeutic Targets consortium. In BioVU, genetically elevated FGF23 was associated with higher heart failure risk, specifically heart failure with preserved ejection fraction, particularly among individuals with low genetically predicted eGFR.
Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_07_28_CJN00960122.mp3.
Keywords: FGF23; Mendelian randomization analysis; heart failure; human genetics; mineral metabolism.
Copyright © 2022 by the American Society of Nephrology.