Treating Public Health Dilemma of Gingival Recession by the Dehydrated Amnion Allograft: A 5-Year Longitudinal Study

Aim: This study aimed to evaluate the efficacy of dehydrated amnion allograft with coronally positioned flap procedure in paired Miller's class I recession defects.

Methods: A total of 51 subjects were included in the study with bilateral Miller's class I gingival recession defects. In the test group, patients were treated with an amniotic membrane (AM) with a coronally positioned flap, while in the control group, patients were treated with coronally positioned flap alone. Clinical parameters such as recession depth, recession width (RW), probing depth (PD), relative attachment level (RAL), width of keratinized gingiva (WKG), and thickness of keratinized gingiva (TKG) were recorded at baseline and after 5 years of follow-up.

Result: The mean baseline recession was 2.95 ± 0.89 in the test group and 2.70 ± 0.85 in the control group, and both were statically non-significant. At the end of 6 months, all the parameters, when compared with the baseline, showed a significant improvement. Intergroup comparison showed the non-significant difference in all settings except the TKG.

Conclusion: AM proved to help improve the TKG. This increase in thickness helps in the long-term maintenance of the gingival margin in Miller's class I recession defect.

Fibroblast Growth Factor 23 and Long-Term Cardiac Function: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Although FGF23 (fibroblast growth factor 23) is associated with heart failure and atrial fibrillation, the mechanisms driving these associations are unclear. Sensitive measures of cardiovascular structure and function may provide mechanistic insight behind the associations of FGF23 with various cardiovascular diseases.

METHODS

In MESA (the Multi-Ethnic Study of Atherosclerosis), we evaluated the associations of baseline serum FGF23 (2000-2002) with measures of left ventricular (LV) and left atrial mechanical function on cardiac magnetic resonance at 10-year follow-up (2010-2012).

RESULTS

Of 2276 participants with available FGF23 and cardiac magnetic resonance at 10-year follow-up, participants with higher FGF23 levels were more likely White race, taking antihypertensive medications, and had lower kidney function. After covariate adjustment, FGF23 was associated with higher LV mass (β coefficient per 1 SD higher, 1.14 [95% CI, 0.16-2.12], P=0.02), worse LV global circumferential strain (β coefficient per 1 SD higher, 0.15 [95% CI, 0.05-0.25], P=0.003), worse LV midwall circumferential strain (β coefficient per 1 SD higher, 0.20 [95% CI, 0.08-0.31], P=0.001), and lower left atrial total emptying fraction (β coefficient per 1 SD higher, -0.52 [95% CI, -1.02 to -0.02], P=0.04). These associations were consistent across racial/ethnic groups and the spectrum of glomerular filtration rates. FGF23 was not associated with the presence of myocardial scar (odds ratio per 1 SD higher, 1.12 [95% CI, 0.86-1.45], P=0.42).

CONCLUSIONS

In a multiethnic, community-based cohort, baseline FGF23 levels were independently associated with higher LV mass, lower LV systolic function, and reduced left atrial function over long-term follow-up. These findings provide potential mechanistic insight into associations of FGF23 with incident heart failure and atrial fibrillation.

Fibroblast Growth Factor 23 and Exercise Capacity in Heart Failure with Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is characterized by left ventricular hypertrophy and decreased exercise capacity. Fibroblast growth factor 23 (FGF23), a hormone involved in phosphate, vitamin D, and iron homeostasis, is linked to left ventricular hypertrophy and HF. We measured c-terminal FGF23 (cFGF23) and intact FGF23 (iFGF23) levels and examined their associations with exercise capacity in patients with HFpEF.

METHODS AND RESULTS

Using multivariable linear regression and linear mixed models, we studied the associations of cFGF23 and iFGF23 with baseline and mean weekly change over 24 weeks in peak oxygen consumption and 6-minute walk distance in individuals enrolled in the Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in HFpEF trial. Our study population included 172 individuals with available plasma for cFGF23 and iFGF23 measurements. Median (25th-75th percentile) baseline cFGF23 and iFGF23 levels were 208.7 RU/mL (132.1-379.5 RU/mL) and 90.3 pg/mL (68.6-128.5 pg/mL), respectively. After adjustment for cardiovascular disease and hematologic and kidney parameters, higher cFGF23 was independently associated with a lower peak oxygen consumption at baseline. Higher iFGF23 was independently associated with shorter 6-minute walk distance at baseline. No significant associations were appreciated with the longitudinal outcomes.

CONCLUSIONS

In patients with HFpEF, higher FGF23 levels are independently associated with decreased exercise capacity at baseline.

Over-under cartilage tympanoplasty: technique, results and a call for improved reporting

OBJECTIVE

This study aimed to describe the microscopic over-under cartilage tympanoplasty technique, provide hearing results and detail clinically significant complications.

METHOD

This was a retrospective case series chart review study of over-under cartilage tympanoplasty procedures performed by the senior author between January 2015 and January 2019 at three tertiary care centres. Cases were excluded for previous or intra-operative cholesteatoma, if a mastoidectomy was performed during the procedure or if ossiculoplasty was performed. Hearing results and complications were obtained.

RESULTS

Sixty-eight tympanoplasty procedures met the inclusion criteria. The median age was 13 years (range, 3-71 years). The mean improvement in pure tone average was 6 dB (95 per cent confidence interval 4-9 dB; p < 0.0001). The overall perforation closure rate was 97 per cent (n = 66). Revision surgery was recommended for a total of 6 cases (9 per cent) including 2 post-operative perforations, 1 case of middle-ear cholesteatoma and 3 cases of external auditory canal scarring.

CONCLUSION

Over-under cartilage tympanoplasty is effective at improving clinically meaningful hearing with a low rate of post-operative complications.

Over-under cartilage tympanoplasty: technique, results and a call for improved reporting

OBJECTIVE

This study aimed to describe the microscopic over-under cartilage tympanoplasty technique, provide hearing results and detail clinically significant complications.

METHOD

This was a retrospective case series chart review study of over-under cartilage tympanoplasty procedures performed by the senior author between January 2015 and January 2019 at three tertiary care centres. Cases were excluded for previous or intra-operative cholesteatoma, if a mastoidectomy was performed during the procedure or if ossiculoplasty was performed. Hearing results and complications were obtained.

RESULTS

Sixty-eight tympanoplasty procedures met the inclusion criteria. The median age was 13 years (range, 3-71 years). The mean improvement in pure tone average was 6 dB (95 per cent confidence interval 4-9 dB; p < 0.0001). The overall perforation closure rate was 97 per cent (n = 66). Revision surgery was recommended for a total of 6 cases (9 per cent) including 2 post-operative perforations, 1 case of middle-ear cholesteatoma and 3 cases of external auditory canal scarring.

CONCLUSION

Over-under cartilage tympanoplasty is effective at improving clinically meaningful hearing with a low rate of post-operative complications.

Nasal polyps with osseous metaplasia: A misunderstood situation

Osseous metaplasia in nasal polyps is rare but benign. To exclude dangerous lesions, sending the entirety of histological samples is mandatory in cases presenting with clustered densities on CT scan. Microdebrider should not be used for this surgery.

The combination of insulin resistance and visceral adipose tissue estimation improves the performance of metabolic syndrome as a predictor of type 2 diabetes

AIMS

To assess the performance of metabolic syndrome as a predictor of type 2 diabetes in a model that also includes both a measure of insulin resistance and a metabolic score for visceral fat, and to propose a novel metabolic syndrome definition.

METHODS

In a prospective Metabolic Syndrome Cohort (n=6143), we evaluated improvements in type 2 diabetes risk prediction using International Diabetes Federation-defined and Adult Treatment Panel III-defined metabolic syndrome, after inclusion in the model of updated homeostatic model assessment of insulin resistance and a metabolic score for visceral fat. We also developed a modified metabolic syndrome construct, 'MS-METS', which used the metabolic score for visceral fat instead of waist circumference to evaluate improved predictive performance for risk of developing type 2 diabetes.

RESULTS

Participants who had metabolic syndrome as defined by both the Adult Treatment Panel III and the International Diabetes Federation criteria had a higher risk of type 2 diabetes compared to participants who did not meet these criteria. Addition of updated homeostatic model assessment of insulin resistance and metabolic score for visceral fat to both metabolic syndrome definitions increased predictive performance for type 2 diabetes risk. Homeostatic model assessment of insulin resistance was the only additional predictor of type 2 diabetes in participants without metabolic syndrome. Conversely, in participants with metabolic syndrome, the use of the metabolic score for visceral fat was the stronger added predictor for type 2 diabetes. When evaluating participants using the MS-METS definition we observed the largest improvement in predictive ability for type 2 diabetes risk and a significant reduction in risk overestimation compared to evaluation using metabolic syndrome defined according to the International Diabetes Federation and Adult Treatment Panel III criteria alone.

CONCLUSION

Inclusion of updated homeostatic model assessment of insulin resistance and metabolic score for visceral fat increases performance of metabolic syndrome in prediction of type 2 diabetes. Assessment of insulin resistance could be more useful than conventional metabolic syndrome and assessment of visceral adipose tissue could be more useful in people with metabolic syndrome. Metabolic syndrome as defined using our modified MS-METS construct improved the accuracy of type 2 diabetes prediction.

Apparent Treatment-Resistant Hypertension Assessed by Office and Ambulatory Blood Pressure in Chronic Kidney Disease-A Report from the Chronic Renal Insufficiency Cohort Study

Background

Apparent treatment-resistant hypertension is common in patients with CKD. Whether measurement of 24-hour ambulatory BP monitoring is valuable for risk-stratifying patients with resistant hypertension and CKD is unclear.

Methods

We analyzed data from the Chronic Renal Insufficiency Cohort study, a prospective study of participants (n=1186) with CKD. Office BP was measured using standardized protocols; ambulatory BP was measured using Spacelabs monitors. Apparent treatment-resistant hypertension was defined on the basis of office BP, ambulatory BP monitoring, and use of more than three antihypertensive medications. Outcomes were composite cardiovascular disease, kidney outcomes, and mortality. Groups were compared using Cox regression analyses with a control group of participants without apparent treatment-resistant hypertension.

Results

Of 475 participants with apparent treatment-resistant hypertension on the basis of office BP, 91.6% had apparent treatment-resistant hypertension confirmed by ambulatory BP monitoring. Unadjusted event rates of composite cardiovascular disease, kidney outcomes, and mortality were higher in participants with ambulatory BP monitoring-defined apparent treatment-resistant hypertension compared with participants without apparent treatment-resistant hypertension. In adjusted analyses, the risks of composite cardiovascular disease (hazard ratio, 1.27; 95% confidence interval [95% CI], 0.59 to 2.7), kidney outcomes (hazard ratio, 1.68; 95% CI, 0.88 to 3.21), and mortality (hazard ratio, 1.27; 95% CI, 0.5 to 3.25) were not statistically significantly higher in participants with ambulatory BP monitoring-defined apparent treatment-resistant hypertension compared with participants without apparent treatment-resistant hypertension.

Conclusions

In our study population with CKD, most patients with apparent treatment-resistant hypertension defined on the basis of office BP have apparent treatment-resistant hypertension confirmed by ambulatory BP monitoring. Although ABPM-defined apparent treatment-resistant hypertension was not independently associated with clinical outcomes, it identified participants at high risk for adverse clinical outcomes.

0139 Associations of Actigraphic Sleep Parameters with Maximal Oxygen Consumption and Resting Metabolism in Well-Functioning Older Adults

Introduction

Both poor sleep and poor cardiorespiratory fitness are common in older age and associated with negative health outcomes. Additionally, among older adults, higher resting metabolic rate (RMR) has been associated with increased morbidity and mortality risk. To evaluate whether, and in what ways, sleep may affect these relationships, we investigated the association of actigraphic sleep indices with cardiorespiratory fitness and RMR in older adults.

Methods

We studied 393 community-dwelling participants in the Baltimore Longitudinal Study of Aging (mean age 73.5±10.3 years, 52% women) who completed 6.7±0.9 nights of wrist actigraphy, RMR testing, and a maximal graded exercise test. Primary predictors included mean actigraphic total sleep time (TST, minutes), sleep efficiency (SE, %), wake after sleep onset (WASO, minutes), and average wake bout length (WBL, minutes). Cardiorespiratory fitness, as measured by maximal oxygen consumption (V O2MAX; ml/kg/min), and RMR (kcal/day) were the primary outcomes.

Results

After adjustment for age, sex, race, body mass index, comorbidity index, and depressive symptoms, longer WBL was associated with lower V O2MAX (β=-0.12, 95% confidence interval (CI)=-0.20, -0.04), greater WASO was associated with lower V O2MAX (β=-0.09, 95% CI=-0.17, -0.01), and greater SE was associated with higher V O2MAX (β=0.12, 95% CI=0.03, 0.20). In addition, longer TST was associated with lower RMR (β=-0.10, 95% CI=-0.19, -0.01) and longer WBL was linked to higher RMR (β=0.12, 95% CI=0.04, 0.21).

Conclusion

In well-functioning older adults, indices of greater wakefulness after sleep onset are linked with poorer cardiorespiratory fitness and higher resting metabolism, while longer and more efficient sleep are associated with better fitness and lower resting metabolic rate. Our findings suggest that sleep disturbance may be linked to disrupted energy homeostasis, evidenced by excessive energy expenditure at rest and inefficient energy utilization in response to maximal demands. Prospective analyses are necessary to determine the nature of these associations.

Support

This study was supported in part by National Institute on Aging (NIA) grants R01AG050507 and T32-AG027668, the NIA Intramural Research Program (IRP), and Research and Development Contract HHSN-260-2004-00012C.

Anemia and Incident End-Stage Kidney Disease

Background

Chronic kidney disease (CKD) progression can be a cause and potentially a consequence of anemia. Previous studies suggesting that anemia is associated with CKD progression have not utilized methodologic approaches to address time-dependent confounding.

Methods

We evaluated the association of anemia (defined using World Health Organization criteria of hemoglobin <12 g/dL in women and <13 g/dL in men) with incident ESRD and all-cause death in individuals with CKD using data from the Chronic Renal Insufficiency Cohort Study. Marginal structural models were used to account for time-dependent confounding.

Results

Among 3919 participants, 1859 (47.4%) had anemia at baseline. Over median follow up of 7.8 years, we observed 1,010 ESRD events and 994 deaths. In multivariable analyses, individuals with anemia had higher risk for ESRD compared to those without (HR 1.62, 95% CI 1.24-2.11). In stratified analyses, the increased risk for incident ESRD with anemia was observed in males (HR 2.15, 95% CI: 1.53-3.02) but not females (HR 1.20, 95% CI 0.82-1.78. The association between anemia and ESRD was significant among all racial/ethnic groups except non-Hispanic blacks (non-Hispanic white, HR 2.16, 95% CI 1.53-3.06; Hispanic, HR 1.92, 1.04-3.51; others, HR 2.94; 95% CI 1.16-7.44; non-Hispanic black, HR 1.39; 95% CI 0.95-2.02). There was no association between anemia and all-cause death.

Conclusions

In this cohort, anemia was independently associated with increased risk for incident ESRD. Future work is needed to evaluate the mechanisms by which anemia leads to CKD progression as well as the impact of novel therapeutic agents to treat anemia.

Burden and Outcomes of Heart Failure Hospitalizations in Adults With Chronic Kidney Disease

BACKGROUND

Data on rates of heart failure (HF) hospitalizations, recurrent hospitalizations, and outcomes related to HF hospitalizations in chronic kidney disease (CKD) are limited.

OBJECTIVES

This study examined rates of HF hospitalizations and re-hospitalizations within a large CKD population and evaluated the burden of HF hospitalizations with the risk of subsequent CKD progression and death.

METHODS

The prospective CRIC (Chronic Renal Insufficiency Cohort) study measured the estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (ACR) at baseline. The crude rates and rate ratios of HF hospitalizations and 30-day HF re-hospitalizations were calculated using Poisson regression models. Cox regression was used to assess the association of the frequency of HF hospitalizations within the first 2 years of follow-up with risk of subsequent CKD progression and death.

RESULTS

Among 3,791 participants, the crude rate of HF admissions was 5.8 per 100 person-years (with higher rates of HF with preserved ejection fraction vs. HF with reduced ejection fraction). The adjusted rate of HF was higher with a lower eGFR (vs. eGFR >45 ml/min/1.73 m²); the rate ratios were 1.7 and 2.2 for eGFR 30 to 44 and <30 ml/min/1.73 m² (vs. >45 ml/min/1.73 m²), respectively. Similarly, the adjusted rates of HF hospitalization were significantly higher in those with higher urine ACR (vs. urine ACR <30 mg/g); the rate ratios were 1.9 and 2.6 for urine ACR 30 to 299 and ≥300 mg/g, respectively. Overall, 20.6% of participants had a subsequent HF re-admission within 30 days. HF hospitalization within 2 years of study entry was associated with greater adjusted risks for CKD progression (1 hospitalization: hazard ratio [HR]: 1.93; 95% confidence interval [CI]: 1.40 to 2.67; 2+ hospitalizations: HR: 2.14; 95% CI: 1.30 to 3.54) and all-cause death (1 hospitalization: HR: 2.20; 95% CI: 1.71 to 2.84; 2+ hospitalizations: HR: 3.06; 95% CI: 2.23 to 4.18).

CONCLUSIONS

Within a large U.S. CKD population, the rates of HF hospitalizations and re-hospitalization were high, with even higher rates across categories of lower eGFR and higher urine ACR. Patients with CKD hospitalized with HF had greater risks of CKD progression and death. HF prevention and treatment should be a public health priority to improve CKD outcomes.

Profile of osteoarticular tuberculosis in children

OBJECTIVE

To determine clinical profile of osteoarticular tuberculosis (TB) in children.

METHODS

Cross-sectional analysis from 2007 to 2013. All patients diagnosed with bone TB, spinal TB or TB abscesses were included.

RESULTS

Out of 1318 children with TB, 39 (2.96%) had osteoarticular TB, of which 16 (42%) had osteomyelitis, 8 (20.5%) had spinal involvement, 7 (17.9%) had TB synovitis, 2 (5.1%) had psoas abscess and 6 (15.4%) had abscesses. The mean age of presentation was 7.1 ± 3.5 years (range 2-14 years). Of the 33 cases in which a culture was done, 25 (64%) showed a positive culture. Drug sensitivity tests were done in 21 patients of which 10 (47.6%) tested were drug resistant, of which 4 (36.4%) were multidrug resistant (MDR), 2 (18.2%) were extensively drug resistant (XDR), 3 were pre-XDR (27.3%) and 1 was polyresistant (9.1%). Nine (23.1%) patients had TB in the past with a treatment duration of 8.3 ± 5.3 months. Contact with a TB patient had occurred in 10 (25.6%) cases. Associated pulmonary TB were seen in 6 (15.39%) and TB meningitis were seen in 1 (2.6%) patients. Surgical intervention was needed in 11 (28.2%) patients of which 5 (45.5%) underwent curettage, drainage was done in 1 (9.1%), arthrotomy in 4 (36.4%) and spinal surgery in 1 (9.1%) patient.

CONCLUSION

Drug resistant osteoarticular TB is an emerging problem in children.

Superior Vena Cava Syndrome and Hypoxic Ischemic Encephalopathy Secondary to a Massive, Right-Sided Immature Cervical Teratoma

Cervical teratomas are a rare form of fetal teratoma that can grow to massive size. Generally, these masses can be surgically excised after birth with excellent physical and functional prognosis because the benign variants respect anatomical borders. The primary complications of these masses are associated with compromise of the trachea and esophagus: upper airway obstruction and polyhydramnios. We report the first documented occurrence of superior vena cava syndrome and hypoxic ischemic encephalopathy associated with a massive, right-sided cervical teratoma. This case highlights that when cervical teratomas are right-sided and sufficiently large, they can extend inferiorly and compromise central venous return to the heart. This unique presentation would likely have required fetal surgical excision to avoid catastrophic cerebral injury.

Efficacy and Safety of Mineralocorticoid Receptor Antagonists in Patients With Heart Failure and Chronic Kidney Disease

Mineralocorticoid receptor antagonists (MRA) improve clinical outcomes in patients with heart failure with reduced ejection fraction (HFrEF) and reduce risk of heart failure (HF) hospitalization in patients with heart failure with preserved ejection fraction (HFpEF). However, the benefit and risks of MRA use are not clear in HF patients and chronic kidney disease (CKD) with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². We conducted a systematic review evaluating the efficacy and safety of MRA in patients with HF and CKD. PubMed, Embase, and Cochrane Central databases were searched for relevant studies on patients with HF and reduced renal function (defined as eGFR <60 mL/min/1.73 m²). Seven studies with 5,522 patients were included. We found 3 studies in patients with HFrEF, 1 study with HFpEF, and 2 in acute HF and 1 with mixed patient population of HF. Post hoc analyses from randomized controlled trials demonstrated reduction of risk in the primary end point (adverse cardiovascular outcomes and/or all-cause mortality and/or HF hospitalization) with MRA use in the CKD subgroup (eGFR 30 to 60 mL/min/1.73 m²) despite a greater risk of hyperkalemia and higher rates of drug discontinuation. In 3 observational studies, propensity score matching was performed to compare patients treated with and without MRA and did not identify benefits, but conclusions from these studies were limited due to residual confounding and concern for bias. In conclusion, benefits of MRA use in HF appear to be consistent in patients with reduced renal function (eGFR 30 to 60 mL/min/1.73 m).

Hepatocellular carcinoma tumour burden score to stratify prognosis after resection

BACKGROUND

Although the Barcelona Clinic Liver Cancer (BCLC) staging system has been largely adopted in clinical practice, recent studies have emphasized the need for further refinement and subclassification of this system.

METHODS

Patients who underwent hepatectomy with curative intent for BCLC-0, -A or -B hepatocellular carcinoma (HCC) between 2000 and 2017 were identified using a multi-institutional database. The tumour burden score (TBS) was calculated, and overall survival (OS) was examined in relation to TBS and BCLC stage.

RESULTS

Among 1053 patients, 63 (6·0 per cent) had BCLC-0, 826 (78·4 per cent) BCLC-A and 164 (15·6 per cent) had BCLC-B HCC. OS worsened incrementally with higher TBS (5-year OS 77·9, 61 and 39 per cent for low, medium and high TBS respectively; P < 0·001). No differences in OS were noted among patients with similar TBS, irrespective of BCLC stage (61·6 versus 58·9 per cent for BCLC-A/medium TBS versus BCLC-B/medium TBS, P = 0·930; 45 versus 13 per cent for BCLC-A/high TBS versus BCLC-B/high TBS, P = 0·175). Patients with BCLC-B HCC and a medium TBS had better OS than those with BCLC-A disease and a high TBS (58·9 versus 45 per cent; P = 0·005). On multivariable analysis, TBS remained associated with OS among patients with BCLC-A (medium TBS: hazard ratio (HR) 2·07, 95 per cent c.i. 1·42 to 3·02, P < 0·001; high TBS: HR 4·05, 2·40 to 6·82, P < 0·001) and BCLC-B (high TBS: HR 3·85, 2·03 to 7·30; P < 0·001) HCC. TBS could also stratify prognosis among patients in an external validation cohort (5-year OS 79, 51·2 and 28 per cent for low, medium and high TBS respectively; P = 0·010).

CONCLUSION

The prognosis of patients with HCC varied according to the BCLC stage but was largely dependent on the TBS.

Renal Dysfunction in Heart Failure With Preserved Ejection Fraction: Insights From the RELAX Trial

BACKGROUND

Patients with heart failure with preserved ejection fraction (HFpEF) and chronic kidney disease (CKD) represent a high-risk phenotype. The Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure with Preserved Ejection Fraction (RELAX) trial enrolled a high proportion of CKD participants, allowing investigation into differences in HFpEF by CKD status.

METHODS AND RESULTS

Among 212 participants, we investigated the associations of CKD with biomarkers, cardiac structure, and exercise capacity, and identified predictors of change in estimated glomerular filtration rate (eGFR) over trial follow-up. CKD participants (eGFR ≤60 mL/min/1.73m²) were older, had more comorbidities, and had worse diastolic function. Lower eGFR was associated with higher levels of endothelin-1, N-terminal pro-B-type natriuretic peptide, aldosterone, uric acid, and biomarkers of fibrosis (P < .05 for all). Whereas lower eGFR was associated with worse peak oxygen consumption (VO₂) after adjustment for demographics, clinical comorbidities, exercise modality, ejection fraction, and chronotropic index (β coefficient per 1 SD decrease in eGFR: -0.61, 95% CI: -1.01, -0.22, P = .002), this association was attenuated after further adjustment for hemoglobin (β coefficient: -0.26, 95% CI: -0.68, 0.16, P = .22). Hemoglobin mediated 35% of the association between eGFR and peak VO₂. Sildenafil therapy was independently associated with worsening eGFR over the trial (β coefficient: -2.79, 95% CI: -5.34, -0.24, P = .03).

CONCLUSION

Renal dysfunction in HFpEF is characterized by echocardiographic and biomarker profiles indicative of more advanced disease, and reduced hemoglobin is a strong mediator of the association between renal dysfunction and low exercise capacity. Sildenafil therapy was associated with worsening of renal function in RELAX.

Serial Fibroblast Growth Factor 23 Measurements and Risk of Requirement for Kidney Replacement Therapy: The CRIC (Chronic Renal Insufficiency Cohort) Study

RATIONALE & OBJECTIVE

Studies using a single measurement of fibroblast growth factor 23 (FGF-23) suggest that elevated FGF-23 levels are associated with increased risk for requirement for kidney replacement therapy (KRT) in patients with chronic kidney disease. However, the data do not account for changes in FGF-23 levels as kidney disease progresses.

STUDY DESIGN

Case-cohort study.

SETTING & PARTICIPANTS

To evaluate the association between serial FGF-23 levels and risk for requiring KRT, our primary analysis included 1,597 individuals in the Chronic Renal Insufficiency Cohort Study who had up to 5 annual measurements of carboxy-terminal FGF-23. There were 1,135 randomly selected individuals, of whom 266 initiated KRT, and 462 individuals who initiated KRT outside the random subcohort.

EXPOSURE

Serial FGF-23 measurements and FGF-23 trajectory group membership.

OUTCOMES

Incident KRT.

ANALYTICAL APPROACH

To handle time-dependent confounding, our primary analysis of time-updated FGF-23 levels used time-varying inverse probability weighting in a discrete time failure model. To compare our results with prior data, we used baseline and time-updated FGF-23 values in weighted Cox regression models. To examine the association of FGF-23 trajectory subgroups with risk for incident KRT, we used weighted Cox models with FGF-23 trajectory groups derived from group-based trajectory modeling as the exposure.

RESULTS

In our primary analysis, the HR for the KRT outcome per 1 SD increase in the mean of natural log-transformed (ln)FGF-23 in the past was 1.94 (95% CI, 1.51-2.49). In weighted Cox models using baseline and time-updated values, elevated FGF-23 level was associated with increased risk for incident KRT (HRs per 1 SD ln[FGF-23] of 1.18 [95% CI, 1.02-1.37] for baseline and 1.66 [95% CI, 1.49-1.86] for time-updated). Membership in the slowly and rapidly increasing FGF-23 trajectory groups was associated with ∼3- and ∼21-fold higher risk for incident KRT compared to membership in the stable FGF-23 trajectory group.

LIMITATIONS

Residual confounding and lack of intact FGF-23 values.

CONCLUSIONS

Increasing FGF-23 levels are independently associated with increased risk for incident KRT.

Longitudinal Evolution of Markers of Mineral Metabolism in Patients With CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

The pathogenesis of disordered mineral metabolism in chronic kidney disease (CKD) is largely informed by cross-sectional studies of humans and longitudinal animal studies. We sought to characterize the longitudinal evolution of disordered mineral metabolism during the course of CKD.

STUDY DESIGN

Retrospective analysis nested in a cohort study.

SETTING & PARTICIPANTS

Participants in the Chronic Renal Insufficiency Cohort (CRIC) Study who had up to 5 serial annual measurements of estimated glomerular filtration rate, fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), serum phosphate, and serum calcium and who subsequently reached end-stage kidney disease (ESKD) during follow-up (n = 847).

EXPOSURE

Years before ESKD.

OUTCOMES

Serial FGF-23, PTH, serum phosphate, and serum calcium levels.

ANALYTICAL APPROACH

To assess longitudinal dynamics of disordered mineral metabolism in human CKD, we used "ESKD-anchored longitudinal analyses" to express time as years before ESKD, enabling assessments of mineral metabolites spanning 8 years of CKD progression before ESKD.

RESULTS

Mean FGF-23 levels increased markedly as time before ESKD decreased, while PTH and phosphate levels increased modestly and calcium levels declined minimally. Compared with other mineral metabolites, FGF-23 levels demonstrated the highest rate of change (velocity: first derivative of the function of concentration over time) and magnitude of acceleration (second derivative). These changes became evident approximately 5 years before ESKD and persisted without deceleration through ESKD onset. Rates of changes in PTH and phosphate levels increased modestly and without marked acceleration around the same time, with modest deceleration immediately before ESKD, when use of active vitamin D and phosphate binders increased.

LIMITATIONS

Individuals who entered the CRIC Study at early stages of CKD and who did not progress to ESKD were not studied.

CONCLUSIONS

Among patients with progressive CKD, FGF-23 levels begin to increase 5 years before ESKD and continue to rapidly accelerate until transition to ESKD.

Ferric citrate reduces fibroblast growth factor 23 levels and improves renal and cardiac function in a mouse model of chronic kidney disease

Iron deficiency, anemia, hyperphosphatemia, and increased fibroblast growth factor 23 (FGF23) are common and interrelated complications of chronic kidney disease (CKD) that are linked to CKD progression, cardiovascular disease and death. Ferric citrate is an oral phosphate binder that decreases dietary phosphate absorption and serum FGF23 concentrations while increasing iron stores and hemoglobin in patients with CKD. Here we compared the effects of ferric citrate administration versus a mineral sufficient control diet using the Col4a3 knockout mouse model of progressive CKD and age-matched wild-type mice. Ferric citrate was given to knockout mice for four weeks beginning at six weeks of age when they had overt CKD, or for six weeks beginning at four weeks of age when they had early CKD. Ten-week-old knockout mice on the control diet showed overt iron deficiency, anemia, hyperphosphatemia, increased serum FGF23, hypertension, decreased kidney function, and left ventricular systolic dysfunction. Ferric citrate rescued iron deficiency and anemia in knockout mice regardless of the timing of treatment initiation. Circulating levels and bone expression of FGF23 were reduced in knockout mice given ferric citrate with more pronounced reductions observed when ferric citrate was initiated in early CKD. Ferric citrate decreased serum phosphate only when it was initiated in early CKD. While ferric citrate mitigated systolic dysfunction in knockout mice regardless of timing of treatment initiation, early initiation of ferric citrate also reduced renal fibrosis and proteinuria, improved kidney function, and prolonged life span. Thus, initiation of ferric citrate treatment early in the course of murine CKD lowered FGF23, slowed CKD progression, improved cardiac function and significantly improved survival.

Single Measurements of Carboxy-Terminal Fibroblast Growth Factor 23 and Clinical Risk Prediction of Adverse Outcomes in CKD

RATIONALE & OBJECTIVE

An elevated fibroblast growth factor 23 (FGF-23) level is independently associated with adverse outcomes in populations with chronic kidney disease, but it is unknown whether FGF-23 testing can improve clinical risk prediction in individuals.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Participants in the Chronic Renal Insufficiency Cohort (CRIC) Study (n = 3,789).

EXPOSURE

Baseline carboxy-terminal FGF-23 (cFGF-23) level.

OUTCOMES

All-cause and cardiovascular (CV) mortality, incident end-stage renal disease (ESRD), heart failure (HF) admission, and atherosclerotic events at 3, 5, and 8 years.

ANALYTICAL APPROACH

We assessed changes in model performance by change in area under the receiver operating characteristic curve (ΔAUC), integrated discrimination improvement (IDI), relative IDI, and net reclassification index (NRI) above standard clinical factors. We performed sensitivity analyses, including an additional model comparing the addition of phosphate rather than cFGF-23 level and repeating our analyses using an internal cross-validation cohort.

RESULTS

Addition of a single baseline value of cFGF-23 to a base prediction model improved prediction of all-cause mortality (ΔAUC, 0.017 [95% CI, 0.001-0.033]; IDI, 0.021 [95% CI, 0.006-0.036]; relative IDI, 32.7% [95% CI, 8.5%-56.9%]), and HF admission (ΔAUC, 0.008 [95% CI, 0.0004-0.016]; IDI, 0.019 [95% CI, 0.004-0.034]; relative IDI, 10.0% [95% CI, 1.8%-18.3%]), but not CV mortality, ESRD, or atherosclerotic events at 3 years of follow-up. The NRI did not reach statistical significance for any of the 3-year outcomes. The incremental predictive utility of cFGF-23 level diminished in analyses of the 5- and 8-year outcomes. The cFGF-23 models outperformed the phosphate model for each outcome.

LIMITATIONS

Power to detect increased CV mortality likely limited by low event rate. The NRI is not generalizable without accepted prespecified risk thresholds.

CONCLUSIONS

Among individuals with CKD, single measurements of cFGF-23 improve prediction of risks for all-cause mortality and HF admission but not CV mortality, ESRD, or atherosclerotic events. Future studies should evaluate the predictive utility of repeated cFGF-23 testing.