Fibroblast growth factor 23 and sudden versus non-sudden cardiac death: the Cardiovascular Health Study

Fibroblast growth factor-23 and the risk of cardiovascular diseases and mortality in the general population: A systematic review and dose-response meta-analysis

BACKGROUND

In the past decade, fibroblast growth factor 23 (FGF23) has been recognized as an important biomarker of cardiovascular diseases. This study aimed to assess the relationship between FGF23 and the risk of cardiovascular diseases (CVDs) in general populations.

METHODS

The protocol was registered prospectively in PROSPERO (CRD42021281837) and two authors independently searched for relevant studies in the PubMed, EMBASE, and Cochrane Library databases. The random effects model was applied.

RESULTS

In total, 29 prospective studies involving 135,576 participants were included. In the general population, the category analysis revealed that elevated FGF23 levels were related to increased risks of myocardial infarction (MI) (RR: 1.40, 95%CI: 1.03-1.89), stroke (RR: 1.20, 95%CI: 1.02-1.43), heart failure (HF) (RR: 1.37, 95%CI: 1.23-1.52), CVD events (RR: 1.22, 95%CI: 0.99-1.51), cardiovascular mortality (RR: 1.46, 95%CI: 1.29-1.65), and all-cause mortality (RR: 1.50, 95%CI: 1.29-1.74). In the continuous analysis, per doubling of FGF23 was associated with increased risks of MI (RR: 1.08, 95%CI: 0.94-1.25), stroke (RR: 1.21, 95%CI: 0.99-1.48), HF (RR: 1.24, 95%CI: 1.14-1.35), CVD events (RR: 1.12, 95%CI: 0.99-1.27), cardiovascular mortality (RR: 1.43, 95%CI: 1.09-1.88), all-cause mortality (RR: 1.37, 95%CI: 1.15-1.62). Furthermore, the dose-response analysis demonstrated a potentially non-linear relationship between FGF23 and stroke, HF, and all-cause mortality. In contrast, a potentially linear relationship between FGF23 and cardiovascular mortality was observed (p for non-linearity = 0.73).

CONCLUSION

The present study suggests that increased serum FGF23 levels are positively related to CVD events and mortality in the general population. The clinical application of FGF23 levels to predict CVD risk requires further research.

Decreased Concentration of Fibroblast Growth Factor 23 (FGF-23) as a Result of Supplementation with Selenium and Coenzyme Q10 in an Elderly Swedish Population: A Sub-Analysis

There is a reduced intake of selenium in many countries due to low levels of selenium in the soil. This results in an increased cardiovascular risk. Fibroblast growth factor 23 (FGF-23) is active mainly in the metabolism of vitamin D and phosphorus. However, there are indications that FGF-23 may also provide information both on cardiovascular function and prognosis. The aim of the study was to evaluate the effect of supplementation with selenium and coenzyme Q₁₀ on the FGF-23 concentration in an elderly population with low concentrations of both selenium and coenzyme Q₁₀ and in which the supplementation improved cardiac function and mortality. In a randomised double-blind placebo-controlled trial, FGF-23 was measured in 219 individuals at the start and after 48 months. Selenium yeast (200 µg/day) and coenzyme Q₁₀ (200 mg/day) (n = 118) or placebo (n = 101) were given as a dietary supplement. The intervention time was 48 months. t-Tests, repeated measures of variance, and ANCOVA analyses were used to evaluate the differences in FGF-23 concentration. Following supplementation with selenium and coenzyme Q₁₀, a significantly lower level of FGF-23 could be seen (p = 0.01). Applying 10 years of follow-up, those who later died a cardiovascular death had a significantly higher FGF-23 concentration after 48 months compared with those who survived (p = 0.036), and a significantly lower FGF-23 concentration could be seen in those with a normal renal function compared to those with an impaired renal function (p = 0.027). Supplementation with selenium and coenzyme Q₁₀ to an elderly community-living population low in both substances prevented an increase of FGF-23 and also provided a reduced cardiovascular risk.

Longitudinal change in c-terminal fibroblast growth factor 23 and outcomes in patients with advanced chronic kidney disease

BACKGROUND

Fibroblast growth factor23 (FGF23) is elevated in CKD and has been associated with outcomes such as death, cardiovascular (CV) events and progression to Renal Replacement therapy (RRT). The majority of studies have been unable to account for change in FGF23 over time and those which have demonstrate conflicting results. We performed a survival analysis looking at change in c-terminal FGF23 (cFGF23) over time to assess the relative contribution of cFGF23 to these outcomes.

METHODS

We measured cFGF23 on plasma samples from 388 patients with CKD 3-5 who had serial measurements of cFGF23, with a mean of 4.2 samples per individual. We used linear regression analysis to assess the annual rate of change in cFGF23 and assessed the relationship between time-varying cFGF23 and the outcomes in a cox-regression analysis.

RESULTS

Across our population, median baseline eGFR was 32.3mls/min/1.73m², median baseline cFGF23 was 162 relative units/ml (RU/ml) (IQR 101-244 RU/mL). Over 70 months (IQR 53-97) median follow-up, 76 (19.6%) patients progressed to RRT, 86 (22.2%) died, and 52 (13.4%) suffered a major non-fatal CV event. On multivariate analysis, longitudinal change in cFGF23 was significantly associated with risk for death and progression to RRT but not non-fatal cardiovascular events.

CONCLUSION

In our study, increasing cFGF23 was significantly associated with risk for death and RRT.

Fibroblast growth factor 23 (FGF23) level is associated with ultrafiltration rate in patients on hemodialysis

Fibroblast growth factor 23 (FGF23) is a bone-derived hormone that regulates renal phosphate reabsorption and vitamin D synthesis in renal proximal tubules. High circulating FGF23 levels are associated with increased mortality in patients with chronic kidney disease and those on dialysis. Current data also suggest higher circulating levels of FGF23 are associated with cardiovascular mortality, vascular calcification, and left ventricular hypertrophy; however, evidence on the role of FGF23 in patients on dialysis is incomplete, and some of the data, especially those on cardiovascular disease (CVD), are controversial. This study aimed to evaluate factors associated with FGF23 in hemodialysis patients with or without CVD. Randomly selected 76 patients on maintenance hemodialysis at a single hemodialysis center were enrolled. After the exclusion of eight patients with extremely outlying FGF23 levels, 68 patients, including 48 males and 46 patients with a CVD history, were included in the study. The mean age was 64.4 ± 12.1 years, and the mean dialysis duration was 12.7 ± 7.1 years. Dialysis duration, time-averaged concentration of urea (TAC-urea), ultrafiltration rate (UFR), blood pressure during hemodialysis session, laboratory data, and echocardiographic parameters including interventricular septum thickness (IVST), left ventricular mass indices (LVMI), and ejection fraction were included in univariate and multivariate analyses. The median lgFGF23 levels in the overall cohort and in those with and without CVD were 2.14 (interquartile range, IQR − 0.43 to − 4.23), 2.01 (− 0.52 to 4.12), and 2.59 (0.07 to 4.32), respectively, and there was no difference between the patients with and without CVD (p = 0.14). The univariate analysis revealed that FGF23 was significantly associated with age (r =  − 0.12, p < 0.01), duration of hemodialysis (r =  − 0.11, p < 0.01), TAC-urea (r = 0.29, p = 0.01), UFR (r = 0.26, p = 0.04), alkaline phosphatase (ALP; r =  − 0.27, p = 0.03), corrected serum calcium (cCa; r = 0.32, p < 0.01), serum phosphate (iP, r = 0.57, p < 0.01), intact parathyroid hormone (iPTH; r = 0.38, p < 0.01), IVST (r = 0.30, p = 0.01), and LVMI (r = 0.26, p = 0.04). In multivariate regression analysis, FGF23 was significantly associated with cCa (F = 25.6, p < 0.01), iP (F = 22.5, p < 0.01), iPTH (F = 19.2, p < 0.01), ALP (F = 5.34, p = 0.03), and UFR (F = 3.94, p = 0.05). In addition, the univariate analysis after the categorization of patients according to CVD indicated that FGF23 was significantly associated with cCa (r = 0.34, p = 0.02), iP (r = 0.41, p < 0.01), iPTH (r = 0.39, p = 0.01), and TAC-urea (r = 0.45, p < 0.01) in patients with CVD, whereas only IVST (r = 0.53, p = 0.04) was associated with FGF23 in those without CVD. FGF23 levels in hemodialysis patients were extremely high and associated not only with mineral bone disease-related factors but also with UFR. Additionally, dialysis efficacy might be associated with lower FGF23 levels in patients with CVD.

Useful applications of growth factors for cardiovascular regenerative medicine

Novel advances for cardiovascular diseases (CVDs) include regenerative approaches for fibrosis, hypertrophy, and neoangiogenesis. Studies indicate that growth factor (GF) signaling could promote heart repair since most of the evidence is derived from preclinical models. Observational studies have evaluated GF serum/plasma levels as feasible biomarkers for risk stratification of CVDs. Noteworthy, two clinical interventional published studies showed that the administration of growth factors (GFs) induced beneficial effect on left ventricular ejection fraction (LVEF), myocardial perfusion, end-systolic volume index (ESVI). To date, large scale ongoing studies are in Phase I-II and mostly focussed on intramyocardial (IM), intracoronary (IC) or intravenous (IV) administration of vascular endothelial growth factor (VEGF) and fibroblast growth factor-23 (FGF-23) which result in the most investigated GFs in the last 10 years. Future data of ongoing randomized controlled studies will be crucial in understanding whether GF-based protocols could be in a concrete way effective in the clinical setting.

Fibroblast Growth Factor-23 and Risks of Cardiovascular and Noncardiovascular Diseases: A Meta-Analysis

Background Fibroblast growth factor-23 (FGF-23) has been hypothesized to play a role in the increased risk of cardiovascular disease in patients with CKD.Methods We identified prospective studies reporting associations between FGF-23 concentration and risk of cardiovascular events. Maximally adjusted risk ratios (RRs) were extracted for each outcome and scaled to a comparison of the top versus bottom third of the baseline FGF-23 concentration, and the results aggregated.Results Depending on the assay used, median FGF-23 concentrations were 43-74 RU/ml and 38-47 pg/ml in 17 general population cohorts; 102-392 RU/ml in nine cohorts of patients with CKD not requiring dialysis; and 79-4212 RU/ml and 2526-5555 pg/ml in eight cohorts of patients on dialysis. Overall, comparing participants in the top and bottom FGF-23 concentration thirds, the summary RRs (95% confidence intervals [95% CIs]) were 1.33 (1.12 to 1.58) for myocardial infarction, 1.26 (1.13 to 1.41) for stroke, 1.48 (1.29 to 1.69) for heart failure, 1.42 (1.27 to 1.60) for cardiovascular mortality, and 1.70 (1.52 to 1.91) for all-cause mortality. The summary RR for noncardiovascular mortality, calculated indirectly, was 1.52 (95% CI, 1.28 to 1.79). When studies were ordered by average differences in FGF-23 concentration between the top and bottom thirds, there was no trend in RRs across the studies.Conclusions The similarly-sized associations between increased FGF-23 concentration and cardiovascular (atherosclerotic and nonatherosclerotic) and noncardiovascular outcomes, together with the absence of any exposure-response relationship, suggest that the relationship between FGF-23 and cardiovascular disease risk may be noncausal.

The 24,25 to 25-hydroxyvitamin D ratio and fracture risk in older adults: The cardiovascular health study

25-hydroxyvitamin D [25(OH)D] may not optimally indicate vitamin D receptor activity. Higher concentrations of its catabolic product 24,25-dihydroxyvitmin D [24,25(OH)₂D] and a higher ratio of 24,25(OH)₂D to 25(OH)D (the vitamin D metabolite ratio [VMR]) may provide additional information on receptor activity. We compared the strength of associations of these markers with serum PTH concentrations, hip bone mineral density (BMD), and risk of incident hip fracture in community-living older participants in the Cardiovascular Health Study. Among 890 participants, the mean age was 78years, 60% were women, and the mean 25(OH)D was 28±11ng/ml. In cross-sectional analysis, the strength of association of each vitamin D measure with PTH was similar; a 1% higher 25(OH)D, 24,25(OH)₂D, and VMR were associated with 0.32%, 0.25%, and 0.26% lower PTH, respectively (p<0.05 for all). Among 358 participants with available BMD data, we found no associations of 25(OH)D or VMR with BMD, whereas higher 24,25(OH)₂D was modestly associated with greater hip BMD (1% higher 24,25(OH)₂D associated with 0.04% [95% CI 0.01-0.08%] higher BMD). Risk of incident hip fracture risk was evaluated using a case-cohort design. There were 289 hip fractures during a mean follow up time of 8.4years. Both higher 24,25(OH)₂D and VMR were associated with lower risk of hip fracture (HR per SD higher, 0.73 [0.61, 0.87] and 0.74 [0.61, 0.88], respectively) whereas 25(OH)D was not associated with hip fracture (HR 0.93 [0.79, 1.10]). We conclude that evaluating vitamin D status by incorporating assessment of 24,25(OH)D and the VMR provides information on bone health above and beyond 25(OH)D alone.

FGF23 and Nutritional Metabolism

The discovery of fibroblast growth factor 23 (FGF23) has provided a more complete understanding of the regulation of phosphate and mineral homeostasis in health and in chronic kidney disease. It has also offered new insights into stratification of risk of cardiovascular events and death among patients with chronic kidney disease and the general population. In this review, we provide an overview of FGF23 biology and physiology, summarize clinical outcomes that have been associated with FGF23, discuss potential mechanisms for these observations and their public health implications, and explore clinical and population health interventions that aim to reduce FGF23 levels and improve public health.

The Relation of Serum Potassium Concentration with Cardiovascular Events and Mortality in Community-Living Individuals

BACKGROUND AND OBJECTIVES

Hyperkalemia is associated with adverse outcomes in patients with CKD and in hospitalized patients with acute medical conditions. Little is known regarding hyperkalemia, cardiovascular disease (CVD), and mortality in community-living populations. In a pooled analysis of two large observational cohorts, we investigated associations between serum potassium concentrations and CVD events and mortality, and whether potassium-altering medications and eGFR<60 ml/min per 1.73 m2 modified these associations.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Among 9651 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA) and the Cardiovascular Health Study (CHS), who were free of CVD at baseline (2000-2002 in the MESA and 1989-1993 in the CHS), we investigated associations between serum potassium categories (<3.5, 3.5-3.9, 4.0-4.4, 4.5-4.9, and ≥5.0 mEq/L) and CVD events, mortality, and mortality subtypes (CVD versus non-CVD) using Cox proportional hazards models, adjusting for demographics, time-varying eGFR, traditional CVD risk factors, and use of potassium-altering medications.

RESULTS

Compared with serum potassium concentrations between 4.0 and 4.4 mEq/L, those with concentrations ≥5.0 mEq/L were at higher risk for all-cause mortality (hazard ratio, 1.41; 95% confidence interval, 1.12 to 1.76), CVD death (hazard ratio, 1.50; 95% confidence interval, 1.00 to 2.26), and non-CVD death (hazard ratio, 1.40; 95% confidence interval, 1.07 to 1.83) in fully adjusted models. Associations of serum potassium with these end points differed among diuretic users (Pinteraction<0.02 for all), such that participants who had serum potassium ≥5.0 mEq/L and were concurrently using diuretics were at higher risk of each end point compared with those not using diuretics.

CONCLUSIONS

Serum potassium concentration ≥5.0 mEq/L was associated with all-cause mortality, CVD death, and non-CVD death in community-living individuals; associations were stronger in diuretic users. Whether maintenance of potassium within the normal range may improve clinical outcomes requires future study.

FGF-23 and cardiovascular disease: review of literature

PURPOSE OF REVIEW

This review examines associations between fibroblast growth factor 23 (FGF-23) and cardiovascular disease.

RECENT FINDINGS

FGF-23 is a hormone produced by osteocytes and osteoblasts that aids with phosphate excretion by the kidney and acts as a negative feedback regulator for activated vitamin D synthesis. Recent studies have found associations between elevated FGF-23 levels and a number of cardiovascular diseases, including hypertension, left ventricular hypertrophy, endothelial dysfunction, cardiovascular events and mortality.

CONCLUSION

Recent studies have explored the possible effects of FGF-23 on the cardiovascular system. In animal and observational human studies, there is a link between elevated FGF-23 levels and multiple cardiovascular outcomes, including hypertension, left ventricular hypertrophy and cardiovascular events and mortality. Further studies are required to evaluate whether decreasing FGF-23 levels improves cardiovascular outcomes.

Development and Validation of a Sudden Cardiac Death Prediction Model for the General Population

BACKGROUND

Most sudden cardiac death (SCD) events occur in the general population among persons who do not have any prior history of clinical heart disease. We sought to develop a predictive model of SCD among US adults.

METHODS

We evaluated a series of demographic, clinical, laboratory, electrocardiographic, and echocardiographic measures in participants in the ARIC study (Atherosclerosis Risk in Communities) (n=13 677) and the CHS (Cardiovascular Health Study) (n=4207) who were free of baseline cardiovascular disease. Our initial objective was to derive a SCD prediction model using the ARIC cohort and validate it in CHS. Independent risk factors for SCD were first identified in the ARIC cohort to derive a 10-year risk model of SCD. We compared the prediction of SCD with non-SCD and all-cause mortality in both the derivation and validation cohorts. Furthermore, we evaluated whether the SCD prediction equation was better at predicting SCD than the 2013 American College of Cardiology/American Heart Association Cardiovascular Disease Pooled Cohort risk equation.

RESULTS

There were a total of 345 adjudicated SCD events in our analyses, and the 12 independent risk factors in the ARIC study included age, male sex, black race, current smoking, systolic blood pressure, use of antihypertensive medication, diabetes mellitus, serum potassium, serum albumin, high-density lipoprotein, estimated glomerular filtration rate, and QTc interval. During a 10-year follow-up period, a model combining these risk factors showed good to excellent discrimination for SCD risk (c-statistic 0.820 in ARIC and 0.745 in CHS). The SCD prediction model was slightly better in predicting SCD than the 2013 American College of Cardiology/American Heart Association Pooled Cohort risk equations (c-statistic 0.808 in ARIC and 0.743 in CHS). Only the SCD prediction model, however, demonstrated similar and accurate prediction for SCD using both the original, uncalibrated score and the recalibrated equation. Finally, in the echocardiographic subcohort, a left ventricular ejection fraction <50% was present in only 1.1% of participants and did not enhance SCD prediction.

CONCLUSIONS

Our study is the first to derive and validate a generalizable risk score that provides well-calibrated, absolute risk estimates across different risk strata in an adult population of white and black participants without a clinical diagnosis of cardiovascular disease.

Association of inflammatory, lipid and mineral markers with cardiac calcification in older adults

OBJECTIVE

Calcification of the aortic valve and adjacent structures involves inflammatory, lipid and mineral metabolism pathways. We hypothesised that circulating biomarkers reflecting these pathways are associated with cardiac calcification in older adults.

METHODS

We investigated the associations of various biomarkers with valvular and annular calcification in the Cardiovascular Health Study. Of the 5888 participants, up to 3585 were eligible after exclusions for missing biomarker, covariate or echocardiographic data. We evaluated analytes reflecting lipid (lipoprotein (Lp) (a), Lp-associated phospholipase A₂ (LpPLA₂) mass and activity), inflammatory (interleukin-6, soluble (s) CD14) and mineral metabolism (fetuin-A, fibroblast growth factor (FGF)-23) pathways that were measured within 5 years of echocardiography. The relationships of plasma biomarkers with aortic valve calcification (AVC), aortic annular calcification (AAC) and mitral annular calcification (MAC) were assessed with relative risk (RR) regression.

RESULTS

Calcification was prevalent: AVC 59%, AAC 45% and MAC 41%. After adjustment, Lp(a), LpPLA₂ mass and activity and sCD14 were positively associated with AVC. RRs for AVC per SD (95% CI) were as follows: Lp(a), 1.051 (1.022 to 1.081); LpPLA₂ mass, 1.036 (1.006 to 1.066) and LpPLA₂ activity, 1.037 (1.004 to 1.071); sCD14, 1.039 (1.005 to 1.073). FGF-23 was positively associated with MAC, 1.040 (1.004 to 1.078) and fetuin-A was negatively associated, 0.949 (0.911 to 0.989). No biomarkers were significantly associated with AAC.

CONCLUSION

This study shows novel associations of circulating FGF-23 and fetuin-A with MAC, and LpPLA₂ and sCD14 with AVC, confirming that previously reported for Lp(a). Further investigation of Lp and inflammatory pathways may provide added insight into the aetiology of AVC, while study of phosphate regulation may illuminate the pathogenesis of MAC.