Is there an association between elevated or low serum levels of phosphorus, parathyroid hormone, and calcium and mortality in patients with end stage renal disease? A meta-analysis

Secondary hyperparathyroidism in chronic kidney disease: A narrative review focus on therapeutic strategy

Chronic kidney disease (CKD) affects over 10% of the global population. One crucial complication of CKD is secondary hyperparathyroidism (SHPT), marked by elevated parathyroid hormone levels due to hyperphosphataemia, hypocalcaemia, and low active vitamin D from impaired renal function. SHPT increases risks of bone deformities, vascular calcification, cardiovascular events and mortality. This review examines SHPT treatment strategies in patients with CKD. First-line treatments include phosphate binders, vitamin D receptor activators and calcimimetics. When these fail, invasive options like parathyroidectomy (PTX) and thermal ablation are considered. PTX effectively reduces symptoms and improves radiological outcomes, outperforming medical treatment alone in reducing cardiovascular risk and mortality. Thermal ablation techniques, such as microwave, radiofrequency, laser or high-intensity focused ultrasound, offer less invasive alternatives with promising results. Future research should explore the molecular mechanisms of parathyroid gland hyperplasia and evaluate various treatments' impacts.

International variations in serum PTH and calcium levels and their mortality associations in peritoneal dialysis patients: Results from PDOPPS

BACKGROUND

Mineral bone disorder (MBD) in chronic kidney disease (CKD) is associated with high symptom burden, fractures, vascular calcification, cardiovascular disease and increased morbidity and mortality. CKD-MBD studies have been limited in peritoneal dialysis (PD) patients. Here, we describe calcium and parathyroid hormone (PTH) control, related treatments and mortality associations in PD patients.

METHODS

We used data from eight countries (Australia and New Zealand (A/NZ), Canada, Japan, Thailand, South Korea, United Kingdom, United States (US)) participating in the prospective cohort Peritoneal Dialysis Outcomes and Practice Patterns Study (2014-2022) among patients receiving PD for >3 months. We analysed the association of baseline PTH and albumin-adjusted calcium (calciumAlb) with all-cause mortality using Cox regression, adjusted for potential confounders, including serum phosphorus and alkaline phosphatase.

RESULTS

Mean age ranged from 54.6 years in South Korea to 63.5 years in Japan. PTH and serum calciumAlb were measured at baseline in 12,642 and 14,244 patients, respectively. Median PTH ranged from 161 (Japan) to 363 pg/mL (US); mean calciumAlb ranged from 9.1 (South Korea, US) to 9.8 mg/dL (A/NZ). The PTH/mortality relationship was U-shaped, with the lowest risk at PTH 300-599 pg/mL. Mortality was nearly 20% higher at serum calciumAlb 9.6+ mg/dL versus 8.4-<9.6 mg/dL. MBD therapy prescriptions varied substantially across countries.

CONCLUSIONS

A large proportion of PD patients in this multi-national study have calcium and/or PTH levels in ranges associated with substantially higher mortality. These observations point to the need to substantially improve MBD management in PD to optimise patient outcomes.

LAY SUMMARY

Chronic kidney disease-mineral bone disorder (MBD) is a systemic condition, common in dialysis patients, that results in abnormalities in parathyroid hormone (PTH), calcium, phosphorus and vitamin D metabolism. A large proportion of peritoneal dialysis (PD) patients in this current multi-national study had calcium and/or PTH levels in ranges associated with substantially higher risks of death. Our observational study design limits our ability to determine whether these abnormal calcium and PTH levels cause more death due to possible confounding that was not accounted for in our analysis. However, our findings, along with other recent work showing 48-75% higher risk of death for the one-third of PD patients having high phosphorus levels (>5.5 mg/dL), should raise strong concerns for a greater focus on improving MBD management in PD patients.

Skeletal Muscle Injury in Chronic Kidney Disease-From Histologic Changes to Molecular Mechanisms and to Novel Therapies

Chronic kidney disease (CKD) is associated with significant reductions in lean body mass and in the mass of various tissues, including skeletal muscle, which causes fatigue and contributes to high mortality rates. In CKD, the cellular protein turnover is imbalanced, with protein degradation outweighing protein synthesis, leading to a loss of protein and cell mass, which impairs tissue function. As CKD itself, skeletal muscle wasting, or sarcopenia, can have various origins and causes, and both CKD and sarcopenia share common risk factors, such as diabetes, obesity, and age. While these pathologies together with reduced physical performance and malnutrition contribute to muscle loss, they cannot explain all features of CKD-associated sarcopenia. Metabolic acidosis, systemic inflammation, insulin resistance and the accumulation of uremic toxins have been identified as additional factors that occur in CKD and that can contribute to sarcopenia. Here, we discuss the elevation of systemic phosphate levels, also called hyperphosphatemia, and the imbalance in the endocrine regulators of phosphate metabolism as another CKD-associated pathology that can directly and indirectly harm skeletal muscle tissue. To identify causes, affected cell types, and the mechanisms of sarcopenia and thereby novel targets for therapeutic interventions, it is important to first characterize the precise pathologic changes on molecular, cellular, and histologic levels, and to do so in CKD patients as well as in animal models of CKD, which we describe here in detail. We also discuss the currently known pathomechanisms and therapeutic approaches of CKD-associated sarcopenia, as well as the effects of hyperphosphatemia and the novel drug targets it could provide to protect skeletal muscle in CKD.

Hypocalcemia and cardiovascular mortality in cinacalcet users

BACKGROUND

Calcimimetics are widely used in hemodialysis patients and influence serum calcium levels. Although the Kidney Disease: Improving Global Outcomes guidelines argued that low calcium levels induced by calcimimetics may be harmless, large observational studies investigating the association between hypocalcemia and mortality are scarce. We investigated the association between serum calcium levels and cardiovascular mortality in calcimimetics users using the nationwide Japanese registry for dialysis patients.

METHODS

In this 9-year prospective cohort study, the baseline data were collected at the end of 2009. We enrolled patients on maintenance hemodialysis or hemodiafiltration. We employed three models (baseline, time-dependent and time-averaged) to conduct Cox proportional hazard regression analyses.

RESULTS

Cinacalcet was prescribed to 12.7% (N = 22 853) at baseline. The median observation period was 98 (interquartile range 40-108) months and 108 (interquartile range 59-108) months in the whole cohort (N = 180 136) and in cinacalcet users, respectively. Three-quarters of survivors at the end of 2019 had continued calcimimetic therapy for 10 years, corresponding to a mean annual dropout rate of 2.9%. Hypocalcemia was not associated with cardiovascular mortality in the baseline or time-averaged model. In the time-dependent model, however, the lowest calcium decile (corrected calcium <8.4 mg/dL) was significantly associated with higher cardiovascular mortality than the reference (corrected calcium 8.7-8.9 mg/dL) in both cinacalcet users and all patients [hazard ratio (95% confidence interval) 1.32 (1.00, 1.75) and 1.15 (1.05, 1.26), respectively]. Hypocalcemia was especially associated with sudden death and death due to hemorrhagic stroke, heart failure and ischemic heart disease. Higher rate of fatal and non-fatal cardiovascular events was observed in hypocalcemic patients regardless of cinacalcet usage.

CONCLUSIONS

Our findings suggest that transient hypocalcemia was associated with an increased risk of cardiovascular death independent of cinacalcet usage. We should pay attention to hypocalcemia transiently induced by cinacalcet.

Early arteriovenous fistula failure associated with mortality and major adverse cardiovascular events in patients undergoing incident hemodialysis

BACKGROUND

Arteriovenous fistula (AVF) patency is important for patients undergoing hemodialysis. The association between early AVF failure and the prognosis, including all-cause mortality and major adverse cardiovascular events (MACE), has not been fully investigated. The present study was performed to investigate the association between early AVF failure and 3-year mortality, cardiovascular disease (CVD) mortality, and MACE.

METHODS

We analyzed 358 patients who started hemodialysis in our institution from October 2008 to February 2020. We defined early AVF failure as cases requiring percutaneous transluminal angioplasty or reoperation within 1 year after AVF surgery. The patients were divided into two groups according to the presence or absence of early AVF failure, and the prognosis of each group was examined. The association between early AVF failure and outcomes (3-year all-cause mortality, CVD mortality, and MACE) was determined using Cox proportional hazards regression analysis.

RESULTS

During the 3-year follow-up, 75 (20.9%) patients died (cardiovascular death: n = 39) and 145 patients developed MACE. According to the multivariable analysis, the early AVF failure group had a significantly higher risk of 3-year all-cause mortality (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.09-1.83; p = 0.009), CVD mortality (HR, 1.54; 95% CI, 1.29-2.08; p < 0.001), and MACE (HR, 1.68; 95% CI, 1.25-2.26; p < 0.001). When the patients were stratified by age, early AVF failure was associated with 3-year all-cause mortality in all groups except for the younger group (<65 years of age).

CONCLUSIONS

Early AVF failure was associated with an increased risk of 3-year all-cause mortality, CVD mortality, and MACE.

Cost-effectiveness analysis of cinacalcet vs. paricalcitol in the treatment of hyperparathyroidism secondary to chronic kidney disease

INTRODUCTION

For the reduction of PTH levels, two classes of drugs are available in the Brazilian market: non-selective and selective vitamin D receptor activators and calcimimetics. Among the mentioned drugs, the SUS provides oral calcitriol, paricalcitol and cinacalcet.

OBJECTIVES

Develop cost-effectiveness (CE) and budgetary impact (BI) analysis of cinacalcet versus paricalcitol for patients on dialysis with SHPT, from the perspective of SUS.

METHODOLOGY

A decision tree model was constructed for CE analysis, which considered the outcome of avoided parathyroidectomy and a time horizon of 1 year. As for the BI analysis, two scenarios were considered, one of which was measured demand and other epidemiological, based on data from the Brazilian Society of Nephrology (BSN).

RESULTS

The CE analysis showed that the use of cinacalcet results in one-off savings of R$1,394.64 per year and an incremental effectiveness of 0.08, in relation to avoided parathyroidectomy. The incremental CE ratio (ICER) was - R$ 17,653.67 per avoided parathyroidectomy for cinacalcet, as it was more effective and cheaper compared to paricalcitol. As for the BI analysis, it was estimated that the incremental BI with the expansion of the use of cinacalcet in the SUS will be between - R$ 1,640,864.62 and R$ 166,368.50 in the first year, considering the main and the epidemiological scenarios. At the end of 5 years after the expansion of use, an BI was estimated between - R$ 10,740,743.86 and - R$ 1,191,339.37; considering the same scenarios.

CONCLUSION

Cinacalcet was dominant to avoid parathyroidectomies, being cost-effective.

Cost-effectiveness analysis of intravenous paricalcitol vs. oral calcitriol in the treatment of hyperparathyroidism secondary to chronic kidney disease

INTRODUCTION

Hyperparathyroidism (SHPT) secondary to chronic kidney disease (CKD) is characterized by high levels of parathyroid hormone (PTH), hyperplasia of the parathyroid glands and cardiovascular disease. Selective and non-selective and selective vitamin D-receptor activators, calcimimetics, are available in the Brazilian market to reduce PTH levels.

OBJECTIVES

To develop a cost-effectiveness (C/E) and budgetary impact (BI) analysis of intravenous paricalcitol vs. oral calcitriol for patients on dialysis with SHPT, from the perspective of the Brazilian Public Health Care System (SUS).

METHODOLOGY

We built a decision-tree model to analyze C/E, which considered the outcome of avoided death and a time horizon of 1 year. As for the BI analysis, two scenarios were considered, one of demand and one of epidemiological approach, based on data from the Brazilian Society of Nephrology.

RESULTS

The analysis showed that the C/E ratio was R$ 1,213.68 per year, and an incremental effectiveness of 0.032, referring to avoided death. The incremental C/E ratio was R$37,927.50 per death averted by paricalcitol. It was estimated that the incremental BI with the expansion of paricalcitol use will be between R$1,600,202.28 and R$4,128,565.65 in the first year, considering the main and epidemiological scenarios. At the end of 5 years after the expansion of its use, an incremental BI was estimated between R$ 48,596,855.50 and R$ 62,90,555.73.

CONCLUSION

Intravenous paricalcitol has superior efficacy and similar safety to oral calcitriol, reducing the overall mortality of dialysis patients, although it implies a higher cost.

Análise de custo-efetividade do paricalcitol intravenoso vs. calcitriol oral no tratamento do hiperparatireoidismo secundário à doença renal crônica

Resumo Introdução: O hiperparatireoidismo secundário (HPTS) à doença crônica renal (DRC) é caracterizado por elevados níveis de paratormônio (PTH), hiperplasia das glândulas paratireoides e doença cardiovascular. Para a redução dos níveis do PTH, estão disponíveis no mercado brasileiro os ativadores não seletivos e seletivos do receptor da vitamina D e os calcimiméticos. Objetivos: Desenvolver análise de custo-efetividade (C/E) e de impacto orçamentário (IO) do paricalcitol intravenoso vs. calcitriol oral para pacientes em diálise com HPTS, na perspectiva do Sistema Único de Saúde. Metodologia: Foi construído um modelo de árvore de decisão para a análise de C/E, que considerou o desfecho morte evitada e um horizonte temporal de 1 ano. Quanto à análise de IO, foram considerados dois cenários, sendo um de demanda aferida e um de abordagem epidemiológica, baseado nos dados da Sociedade Brasileira de Nefrologia. Resultados: A análise mostrou que a relação de C/E foi de R$ 1.213,68 ao ano, e uma efetividade incremental de 0,032, referente à morte evitada. A razão de C/E incremental foi de R$ 37.927,50 por morte evitada para o paricalcitol. Estimou-se que o IO incremental com a ampliação do uso do paricalcitol estará entre R$ 1.600.202,28 e R$ 4.128.565,65 no primeiro ano, considerando os cenários principal e o epidemiológico. Já no fim de 5 anos após a ampliação do uso, estimou-se IO incremental entre R$ 48.596.855,50 e R$ 62.90.555,73. Conclusão: O paricalcitol intravenoso tem eficácia superior e segurança semelhante ao comparador calcitriol oral, diminuindo a mortalidade geral dos pacientes em diálise, embora implique maior custo.

Association between Serum Inorganic Phosphorus Levels and Adverse Outcomes in Chronic Kidney Disease: The Fukushima CKD Cohort Study

Objective Although an association between serum inorganic phosphorus levels and a poor prognosis has been noted in dialysis patients, these associations have been insufficiently reported in non-dialysis-dependent chronic kidney disease (NDD-CKD) patients. This study attempted to determine the association between serum inorganic phosphorus levels and adverse outcomes in Japanese NDD-CKD patients. Methods We investigated the relationships between serum inorganic phosphorus levels and adverse outcomes, such as kidney events, cardiovascular events, and all-cause death, in Japanese NDD-CKD patients using longitudinal data from the Fukushima CKD Cohort Study with a median follow-up period of 2.8 years. The study evaluated 822 patients with NDD-CKD enrolled between June 2012 and July 2014. A kidney event was defined as a combination of doubling of the baseline serum creatinine or end-stage renal disease. Cox regression was performed to analyze the relationships of the quartile of the serum inorganic phosphorus with kidney events, cardiovascular events, and all-cause death. Results The frequency of kidney events per 1,000 person-years exhibited a U-shaped distribution based on serum inorganic phosphorus levels, with these levels not significantly associated with an increased risk of cardiovascular events and all-cause death. A multivariable Cox regression analysis showed an increased risk of kidney events for the highest quartile of the serum inorganic phosphorus levels (≥3.7 mg/dL) versus the second quartile (2.9-3.2 mg/dL, hazard ratio, 3.30; 95% confidence interval, 1.50-7.28; p=0.003). There were no significant associations between the serum calcium levels and adverse outcomes. Conclusion Serum inorganic phosphorus levels were associated with an increased risk of CKD progression in Japanese NDD-CKD patients.

The optimal range of serum intact parathyroid hormone for a lower risk of mortality in the incident hemodialysis patients

The serum intact parathyroid hormone (iPTH) is associated with the prognosis of hemodialysis (HD) patients, however, its optimal range for reducing mortality remains inconsistent. We designed a prospective cohort study of 346 incident HD patients to assess the association between different serum iPTH level and mortality. According to the Kidney Disease Outcomes Quality Initiative (K/DOQI) international guidelines (2003), we divided patients into three groups (iPTH < 150 pg/mL, 150–300 pg/mL and >300 pg/mL). During the median follow-up of 58 months, 157 patients (45.38%) died. Multivariate Cox regression analysis showed that iPTH < 150 pg/mL and >300 pg/mL were associated with all-cause and cardiovascular mortality. Then, we performed a sensitivity analysis of patients divided into 6 serum PTH levels groups according to the folds of the K/DOQI target range. Multivariate Cox regression analysis showed that patients with serum iPTH ≥750 pg/mL, 600–749 pg/mL, 450–599 pg/mL had significantly higher risk of all-cause and cardiovascular mortality compared with those with serum iPTH in the range of 150–299 pg/mL. The association between serum iPTH and mortality shows a U-shaped curve. The optimal serum iPTH level which confers the lowest risk of all-cause and cardiovascular mortality could range from 150 pg/mL to 450 pg/mL in this group of incident HD patients.

The risk of medically uncontrolled secondary hyperparathyroidism depends on parathyroid hormone levels at haemodialysis initiation

BACKGROUND

Optimal parathyroid hormone (PTH) control during non-dialysis chronic kidney disease (ND-CKD) might decrease the subsequent risk of parathyroid hyperplasia and uncontrolled secondary hyperparathyroidism (SHPT) on dialysis. However, the evidence for recommending PTH targets and therapeutic strategies is weak for ND-CKD. We evaluated the patient characteristics, treatment patterns and PTH control over the first year of haemodialysis (HD) by PTH prior to HD initiation.

METHODS

We studied 5683 incident HD patients from 21 countries in Dialysis Outcomes and Practice Patterns Study Phases 4-6 (2009-18). We stratified by PTH measured immediately prior to HD initiation and reported the monthly prescription prevalence of active vitamin D and calcimimetics over the first year of HD and risk of PTH >600 pg/mL after 9-12 months on HD.

RESULTS

The 16% of patients with PTH >600 pg/mL prior to HD initiation were more likely to be prescribed active vitamin D and calcimimetics during the first year of HD. The prevalence of PTH >600 pg/mL 9-12 months after start of HD was greater for patients who initiated HD with PTH >600 (29%) versus 150-300 (7%) pg/mL (adjusted risk difference: 19%; 95% confidence interval : 15%, 23%). The patients with sustained PTH >600 pg/mL after 9-12 months on HD were younger, more likely to be black, and had higher serum phosphorus and estimated glomerular filtration rates at HD initiation.

CONCLUSIONS

Increased PTH before HD start predicted a higher PTH level 9-12 months later, despite greater use of active vitamin D and calcimimetics. More targeted PTH control during ND-CKD may influence outcomes during HD, raising the need for PTH target guidelines in these patients.

Parathyroid Hormone Serum Levels and Mortality among Hemodialysis Patients in the Gulf Cooperation Council Countries: Results from the DOPPS (2012-2018)

BACKGROUND

The prospective Dialysis Outcomes and Practice Patterns Study (DOPPS) has collected data since 2012 in all six Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates). We report the relationship of PTH with mortality in this largest GCC cohort of patients on hemodialysis studied to date.

METHODS

Data were from randomly selected national samples of hemodialysis facilities in GCC-DOPPS phases 5 and 6 (2012-2018). PTH descriptive findings and case mix-adjusted PTH/mortality Cox regression analyses were based on 1825 and 1422 randomly selected patients on hemodialysis, respectively.

RESULTS

Mean patient age was 55 years (median dialysis vintage, 2.1 years). Median PTH ranged from 259 pg/ml (UAE) to 437 pg/ml (Kuwait), with 22% having PTH <150 pg/ml, 24% with PTH of 150-300 pg/ml, 34% with PTH 301-700 pg/ml, and 20% with PTH >700 pg/ml. Patients with PTH >700 pg/ml were younger; on dialysis longer; less likely to be diabetic; have urine >200 ml/d; be prescribed 3.5 mEq/L dialysate calcium; had higher mean serum creatinine and phosphate levels; lower white blood cell counts; and more likely to be prescribed cinacalcet, phosphate binders, or IV vitamin D. A U-shaped PTH/mortality relationship was observed with more than two- and 1.5-fold higher adjusted HR of death at PTH >700 pg/ml and <300 pg/ml, respectively, compared with PTH of 301-450 pg/ml.

CONCLUSIONS

Secondary hyperparathyroidism is highly prevalent among GCC patients on hemodialysis, with a strong U-shaped PTH/mortality relationship seen at PTH <300 and >450 pg/ml. Future studies are encouraged for further understanding this PTH/mortality pattern in relationship to unique aspects of the GCC hemodialysis population.

Parathyroid Hormone Serum Levels and Mortality among Hemodialysis Patients in the Gulf Cooperation Council Countries: Results from the DOPPS (2012–2018)

Background

The prospective Dialysis Outcomes and Practice Patterns Study (DOPPS) has collected data since 2012 in all six Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates). We report the relationship of PTH with mortality in this largest GCC cohort of patients on hemodialysis studied to date.

Methods

Data were from randomly selected national samples of hemodialysis facilities in GCC-DOPPS phases 5 and 6 (2012–2018). PTH descriptive findings and case mix–adjusted PTH/mortality Cox regression analyses were based on 1825 and 1422 randomly selected patients on hemodialysis, respectively.

Results

Mean patient age was 55 years (median dialysis vintage, 2.1 years). Median PTH ranged from 259 pg/ml (UAE) to 437 pg/ml (Kuwait), with 22% having PTH <150 pg/ml, 24% with PTH of 150–300 pg/ml, 34% with PTH 301–700 pg/ml, and 20% with PTH >700 pg/ml. Patients with PTH >700 pg/ml were younger; on dialysis longer; less likely to be diabetic; have urine >200 ml/d; be prescribed 3.5 mEq/L dialysate calcium; had higher mean serum creatinine and phosphate levels; lower white blood cell counts; and more likely to be prescribed cinacalcet, phosphate binders, or IV vitamin D. A U-shaped PTH/mortality relationship was observed with more than two- and 1.5-fold higher adjusted HR of death at PTH >700 pg/ml and <300 pg/ml, respectively, compared with PTH of 301–450 pg/ml.

Conclusions

Secondary hyperparathyroidism is highly prevalent among GCC patients on hemodialysis, with a strong U-shaped PTH/mortality relationship seen at PTH <300 and >450 pg/ml. Future studies are encouraged for further understanding this PTH/mortality pattern in relationship to unique aspects of the GCC hemodialysis population.

Joint Longitudinal Low Calcium High Phosphorus Trajectory Associates with Accelerated Progression, Acute Coronary Syndrome and Mortality in Chronic Kidney Disease

The effects of long-term disturbance of the mineral metabolism on patients with chronic kidney disease (CKD) are unclear. We investigated whether the longitudinal Ca-P (joint calcium and phosphorus) trajectories are associated with incident end-stage renal disease (ESRD), acute coronary syndrome (ACS), and all-cause mortality in patients with CKD. We conducted a prospective cohort study by using data from a 13-year multidisciplinary pre-ESRD care registry. The final study population consisted of 4,237 CKD patients aged 20–90 years with data gathered from 2003 to 2015. Individuals’ Ca-P trajectories were defined using group-based multi-trajectory modeling into three distinct patterns: reference, moderately abnormal, and severely abnormal. Times to ESRD, ACS, and death were analyzed using multiple Cox regression. Compared with those with a “reference” Ca-P trajectory, the adjusted hazard ratios (aHRs) (95% confidence interval [CI]) for incidental ESRD were 5.92 (4.71–7.44) and 15.20 (11.85–19.50) for “moderately abnormal” and “severely abnormal” Ca-P trajectories, respectively. The corresponding aHRs for ACS were 1.94 (1.49–2.52) and 3.18 (2.30–4.39), and for all-cause mortality, they were 1.88 (1.64–2.16) and 2.46 (2.05–2.96) for “moderately abnormal” and “severely abnormal” Ca-P trajectories, respectively. For outcomes of progression to ESRD, the detrimental effects of abnormal Ca-P trajectories were more substantial in patients with CKD stage 3 than those with CKD stage 4 or 5 (p-value for interaction < 0.001). Future studies should validate reliable longitudinal cut-offs of serum phosphorus and consider the “lowering phosphorus— the lower the better, the earlier the better” approach to phosphorus control in CKD.

Influence of Parathyroidectomy on Kidney Graft Function in Secondary and Tertiary Hyperparathyroidism

BACKGROUND

Timing of parathyroidectomy (PTX) remains controversial in candidates for kidney transplant with concomitant renal hyperparathyroidism (HPT). The aim of this retrospective study was to identify the influence of early vs late posttransplant PTX compared to pretransplant PTX on renal graft function and morbidity.

METHODS

This single-center cohort study includes 57 patients with renal HPT and kidney transplantation treated between 2007 and 2017. Ninety-six patients had surgery for renal HPT between 2007 and 2017 as a consecutive sample. Group 1 (n = 30; tertiary HPT), group 2 (n = 66; secondary HPT). Of group 1, 4 patients were excluded for PTX before and after kidney transplantation. In group 2, 20 patients were excluded since they had not undergone kidney transplantation during follow-up. Twelve patients were excluded because of short follow-up (kidney transplantation in 2018), and 3 patients were excluded because of transplant failure within 90 days. Twenty-six patients underwent posttransplant PTX (10 patients within 12 months after transplant), and 31 patients had undergone PTX prior to kidney transplantation. Graft function, serum calcium concentrations, parathyroid hormone (PTH) levels, postoperative morbidity, and 90-day mortality were recorded.

RESULTS

Median age was 53.1 years in group 1 and 49.1 years in group 2. Most patients were male (53.8% in group 1; 54.8% in group 2). Median preoperative PTH levels were significantly different with 331.6 pg/mL in group 1 and 667.5 pg/mL in group 2 (P = .003). Creatinine levels changed little from 1.4 mg/dL (range, 0.8-2.5) to 1.7 mg/dL (range, 0.7-7.3) in group 1, and no difference was seen between early or late PTX after transplantation. In group 2, creatinine levels were 8.5 mg/dL (range, 4.6-11.7) before PTX and 8.7 mg/dL (range, 5.1-11.9) after PTX. We saw no correlation between postoperative PTH and kidney function. Thirty-five patients with postoperative PTH < 15 pg/mL displayed a mean postoperative creatinine of 5.5 mg/dL (range, 4.3-6.8), similar to other patients. Both the 30-day and 90-day mortality rates were zero.

CONCLUSIONS

PTX had no negative effect on graft function, whether performed before or after (early or late) kidney transplantation. Surgical cure of renal HPT should be performed as soon as possible to prevent secondary complications and can also be safely carried out early after transplantation.

The association of dialysis adequacy, body mass index, and mortality among hemodialysis patients

Background

Although hemodialysis (HD) adequacy, single-pool Kt/V_urea (spKt/V), is inversely correlated with body size, each is known to affect patient survival in the same direction. Therefore, we sought to examine the relationship between HD adequacy and mortality according to body mass index (BMI) in HD patients and explore a combination effect of BMI and HD adequacy on mortality risk.

Methods

We retrospectively reviewed patient data from the Korean Society of Nephrology registry, a nationwide database of medical records of HD patients, from January 2001 to June 2017. We included patients ≥18 years old who were receiving maintenance HD. Patients were categorized into three groups according to baseline BMI (< 20 (low), 20 to < 23 (normal), and ≥ 23 (high) kg/m²). Baseline spKt/V was divided into six categories.

Results

Among 18,242 patients on HD, the median follow-up duration was 5.2 (IQR, 1.9–8.9) years. Cox regression analysis showed that, compared to the reference (spKt/V 1.2–1.4), lower and higher baseline spKt/V were associated with greater and lower risks for all-cause mortality, respectively. However, among patients with high BMI (n = 5588), the association between higher spKt/V and lower all-cause mortality was attenuated in all adjusted models (P_interaction < 0.001). Compared to patients with normal BMI and spKt/V within the target range (1.2–1.4), those with low BMI had a higher risk for all-cause mortality at all spKt/V levels. However, the gap in mortality risk became narrower for higher values of spKt/V. Compared to patients with normal BMI and spKt/V in the target range, those with high BMI and spKt/V < 1.2 were not at increased risk for mortality despite low dialysis adequacy.

Conclusions

The association between spKt/V and mortality in HD patients may be modified by BMI.

Application of dynamic optimisation for planning a haemodialysis process

BACKGROUND

The aim of the study is to show that optimization tools can be used in planning the haemodialysis process in order to obtain the most effective treatment aimed at removing both urea and phosphorus. To this end we use the IV-compartment model of phosphorus kinetics.

METHODS

The use of the IV-compartment model of phosphorus kinetics forces us to apply new numerical tools which cope with a rebound phenomenon that can occur during haemodialysis. The proposed algorithm solves optimization problems with various constraints imposed on concentrations of urea and phosphorus.

RESULTS

We show that the optimization tools are effective in planning haemodialysis processes aimed at achieving desired levels of urea and phosphorus concentrations at the end of these processes. One of the numerical experiments reported in the paper concerns patients data who experienced a rebound phenomenon during haemodialysis due to a low level of phosphorus concentration.

CONCLUSION

In order to plan haemodialysis processes one should take into account the fact that these processes, in general, are described by different equations in different regions determined by phosphorus concentrations. This follows from the fact that mechanisms modelled by IV-compartment model are activated during dialysis. Therefore, advanced numerical tools have to be used in order to simulate and optimize these processes. The paper shows that these tools can be constructed and effectively applied in planning haemodialysis processes.

International and Racial Differences in Mineral and Bone Disorder Markers and Treatments Over the First 5 Years of Hemodialysis in the Dialysis Outcomes and Practice Patterns Study

RATIONALE & OBJECTIVE

Normalization of parathyroid hormone (PTH), serum calcium, and phosphorus levels may prevent coronary and bone disease in hemodialysis (HD) patients. We describe the trajectory of these mineral bone disorder parameters and treatments during the first 5 years of HD by international region and race.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

33,517 US black/African American, US non-black/African American, European, and Japanese HD patients from the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 5 (2009-2015).

PREDICTOR

Time since HD initiation.

OUTCOMES

Monthly cross-sections of mineral bone disorder parameters (PTH, serum calcium, and phosphorus) and medications (cinacalcet, active vitamin D, and phosphate binders).

RESULTS

Mean PTH levels declined precipitously during the first 4 months of HD in all 4 groups, then steadily increased during the next 4.5 years in the United States/Europe but not in Japan. 3 years after HD initiation (month 36), mean PTH level was highest in US black/African Americans (496 pg/mL), despite greater prescription of cinacalcet (23%) and active vitamin D (85%), and lowest in Japan (151 pg/mL). Mean serum calcium and phosphorus levels increased during the first 4 months of HD. By month 36, the mean calcium level was lower in Japan (8.8 mg/dL) than United States/Europe (9.0-9.1 mg/dL), while the mean phosphorus level was lower in Europe (4.8 mg/dL) than United States/Japan (5.1-5.3 mg/dL).

LIMITATIONS

Lack of data for medication dosages; most patients were not followed from HD onset.

CONCLUSIONS

Large differences exist in the levels, trajectories, and therapies for PTH, calcium, and phosphorus by country and race in the first 5 years of HD. Higher PTH levels were observed in the United States, especially among black/African American patients, despite greater use of cinacalcet and active vitamin D than in Japan or Europe. Potential contributors to differences in PTH levels should be explored to study their impact on PTH management strategies and consequent bone and cardiovascular complications.

A Decision-Analytic Model to Assess the Cost-Effectiveness of Etelcalcetide vs. Cinacalcet

INTRODUCTION

Etelcalcetide is a novel intravenous calcimimetic for the treatment of secondary hyperparathyroidism (SHPT) in haemodialysis patients. The clinical efficacy and safety of etelcalcetide (in addition to phosphate binders and vitamin D and/or analogues [PB/VD]) was evaluated in three phase III studies, including two placebo-controlled trials and a head-to-head study versus the oral calcimimetic cinacalcet.

OBJECTIVE

The objective of this study was to develop a decision-analytic model for economic evaluation of etelcalcetide compared with cinacalcet.

METHODS

We developed a life-time Markov model including potential treatment effects on mortality, cardiovascular events, fractures, and subjects' persistence. Long-term efficacy of etelcalcetide was extrapolated from the reduction in parathyroid hormone (PTH) in the phase III trials and the available data from the outcomes study in cinacalcet (EVOLVE trial). Etelcalcetide was compared with cinacalcet, both in addition to PB/VD. We applied unit costs averaged from five European countries and a range of potential etelcalcetide pricing options assuming parity price to weekly use of cinacalcet and varying it by a 15 or 30% increase.

RESULTS

Compared with cinacalcet, the incremental cost-effectiveness ratio of etelcalcetide was €1,355 per QALY, €24,521 per QALY, and €47,687 per QALY for the three prices explored. The results were robust across the probabilistic and deterministic sensitivity analyses.

CONCLUSIONS

Our modelling approach enabled cost-utility assessment of the novel therapy for SHPT based on the observed and extrapolated data. This model can be used for local adaptations in the context of reimbursement assessment.

Exploring the potential value of improved care for secondary hyperparathyroidism with a novel calcimimetic therapy

AIMS

This study explored the use of a value-based pricing approach for the new calcimimetic etelcalcetide indicated for the treatment of secondary hyperparathyroidism (SHPT) in patients receiving hemodialysis. It used the US payer perspective and applied the cost-effectiveness framework. Because etelcalcetide is an intravenous therapy that can be titrated for individual patients, and because its utilization is yet to be assessed in real world settings, a range of plausible doses were estimated for etelcalcetide to define a range of prices. These were either in relation to the existing oral calcimimetic cinacalcet or compared to no calcimimetic treatment.

MATERIALS AND METHODS

The value-based price of etelcalcetide was determined via a Markov model. This model combined data from the etelcalcetide trials and previously published cost-effectiveness models in SHPT, and allowed extrapolation of treatment effects on mortality, cardiovascular events, fracture, and parathyroidectomy. Several dosing scenarios were explored covering the dose ranges of 30.0-64.18 mg per day for cinacalcet and 1.07-3.11 mg per day for etelcalcetide. These included the mean dose from the etelcalcetide trials, the preliminary defined daily dose, and the expected most common dose in real world. An acceptable price range for etelcalcetide was assessed by comparing the incremental cost-effectiveness ratios obtained with the willingness-to-pay threshold range of $100,000-$300,000/quality-adjusted life-years.

RESULTS

Cost-effectiveness analysis supported value-based prices for etelcalcetide ranging from $21.15-$49.97/mg vs cinacalcet, and $13.79-$119.45/mg vs no calcimimetics.

LIMITATIONS

There is uncertainty around what the real-world dosing will be for etelcalcetide. Another important nuance is that no studies have examined etelcalcetide effects on hard outcomes and, therefore, this modeling exercise relied on an extrapolation approach.

CONCLUSIONS

This cost-effectiveness analysis, including scenarios to address uncertainties, allowed estimation of a value-based price range to aid reimbursement decisions in the US.

Achievement of Kidney Disease: Improving Global Outcomes mineral and bone targets between 2010 and 2014 in incident dialysis patients in France: the Photo-Graphe3 study

Background

Abnormal serum phosphate, calcium and parathyroid hormone (PTH) levels in patients with chronic kidney disease (CKD) undergoing haemodialysis have been associated with poor survival. The French Phosphorus and Calcium Observatory (Photo-Graphe^® 3) aimed to estimate the percentage of CKD patients achieving the three Kidney Disease: Improving Global Outcomes (KDIGO) targets about optimal serum phosphate, calcium and PTH over a 3.5-year follow-up period.

Methods

This was a prospective, multicentre, epidemiological observational study conducted with nephrologists in France, selected using a clustering approach. Eligible patients were adults undergoing intermittent haemodialysis or haemodiafiltration therapy started within the preceding 12 months. Data about clinical events, serum biochemistry and treatment were collected once every 6 months for 2.5 years and 12 months thereafter.

Results

Overall, 9010 incident patients were included (men, 63%; median age, 71 years) of whom 7515 (83.4%) were treated by haemodialysis and 1495 (16.6%) by haemodiafiltration. None had a history of fracture or revascularization while 89 (1%) patients had a history of parathyroidectomy >6 months. Overall, 874 (10%) patients received a kidney graft, 2183 (24%) died and 1148 (13%) were lost to follow-up. The proportion achieving the three KDIGO targets increased significantly from 11% to 16% (P < 0.0001) until Year 2, but remained stable afterwards. The percentage of incident dialysis patients with normal serum phosphate (P < 0.0001) or normal serum calcium (P < 0.0001) levels increased significantly over time, while no significant change was observed for those with controlled PTH.

Conclusion

Less than 20% of patients achieved the KDIGO recommendations although their proportion increased slightly over time.

Phosphorus and mortality risk in end-stage renal disease: A meta-analysis

BACKGROUND

Studies on the association of abnormal serum phosphorus level with all-cause mortality in patients with end-stage renal disease (ESRD) have yielded inconsistent results.

OBJECTIVE

To evaluate the association of abnormal serum phosphorus level with all-cause mortality in patients with ESRD requiring dialysis by conducting a meta-analysis.

METHODS

Pubmed and Embase databases were searched through March 2017 to identify all observational studies that assessed the association between abnormal serum phosphorus level and all-cause mortality risk in patients with ESRD requiring dialysis. Pooled hazard risk (HR) with 95% confidence interval (CI) was calculated for the highest versus referent phosphorus category and lower versus referent phosphorus category, separately.

RESULTS

Nine cohort studies were eligible for analysis. During 12 to 97.6months follow-up duration, 24,463 death events occurred among 1,992,869 ESRD patients. Meta-analysis showed that the pooled HR of all-cause mortality was 1.16 (95% CI 1.06-1.28) for the lower versus referent serum phosphorus category. Similarly, patients with highest serum phosphorus levels were associated with an increased risk of all-cause mortality (HR 1.39; 95% CI 1.31-1.47) compared with those in the referent phosphorus category. Subgroup analyses revealed that the effect of phosphorus on the all-cause mortality risk appeared to be stronger within 2years follow-up.

CONCLUSIONS

Both very high and very low values of phosphorus are independently associated with an increased risk for all-cause mortality in ESRD patients requiring dialysis. This meta-analysis highlighted a non-linear association of serum phosphorus with all-cause mortality among dialysis-dependent ESRD patients.

Evaluation of the Relationship between the Serum Alkaline Phosphatase Level at Dialysis Initiation and All-Cause Mortality: A Multicenter, Prospective Study

Background/Aim

High serum alkaline phosphatase (ALP) levels predict mortality independent of bone metabolism parameters and liver function test results in patients on hemodialysis. The relationship between serum ALP at dialysis initiation and mortality during maintenance dialysis is unknown; therefore, we aimed to identify an association.

Methods

This multicenter, prospective cohort study analyzed 1,213 patients registered in the Aichi Cohort Study of Prognosis in Patients Newly Initiated into Dialysis from October 2011 to September 2013. Patients were divided into 2 groups based on serum ALP levels. All-cause mortality and incidences of cardiovascular events after dialysis initiation were compared using the log-rank test and multivariate Cox proportional hazard regression analysis. We performed stratified analysis based on parathyroid hormone (PTH) levels.

Results

During the follow-up, 109 (18.0%) and 86 (14.1%) patients died in the high ALP group (232 ≥IU/L; High ALP group) and low ALP group (232 <IU/L; Low ALP group), respectively. All-cause mortality was significantly higher in the High ALP group than in the Low ALP group (p = 0.014). The serum ALP level was significantly correlated with the all-cause mortality rate (hazard ratio = 1.17 per 100 IU/L increase of ALP, 95% confidence interval: 1.11–1.24, p < 0.001). The all-cause mortality rate was significantly higher in the High ALP group among patients with low (<150 pg/mL) or normal (150–300 pg/mL) PTH levels (p = 0.012 and p = 0.005, respectively) than in the Low ALP group; there was no significant difference among patients with a high (≥300 pg/mL) PTH level (p = 1.000).

Conclusion

The serum ALP level at dialysis initiation is associated with all-cause mortality during maintenance dialysis.

Differences between 2nd and 3rd generation seric parathormone determination methods on mortality in haemodialysis patients

Parathormone plays a key role in controlling mineral metabolism. PTH is considered a uremic toxin causing cardiovascular damage and cardiovascular mortality in dialysis patients. There are two different assays to measure PTH called 2nd generation or intact PTH (iPTH) and 3rd generation or bioPTH (PTHbio).

OBJECTIVE

To evaluate the differences in mortality of dialysis patients between both assays to measure PTH, as well as the possible prognostic role of the PTHbio/iPTH ratio.

METHODS

145 haemodialysis patients were included with 2-year monitoring including baseline laboratory test and annually thereafter.

RESULTS

21 patients died in the first year and 28 in the second. No correlation was found between PTH, PTHbio and PTHbio/iPTH ratio with mortality. Both PTH have a perfect correlation between them and correlate similarly with other molecules of the mineral metabolism. The extreme baseline values of PTH are those of higher mortality. In survival by iPTH intervals (according to guidelines and COSMOS study), a J curve is observed. When iPTH increases, the ratio decreases, possibly when increasing fragments no. 1-84. There is no greater prognostic approximation on mortality with PTHbio than PTHi. There was also no difference in mortality when progression ratio PTHbio/PTHi was analysed.

CONCLUSIONS

We didn't find any advantages to using bioPTH vs. PTHi as a marker of mortality. BioPTH limits of normality must be reevaluated because its relationship with iPTH is not consistent. Not knowing these limits affects its prognostic value.

A decrease in intact parathyroid hormone (iPTH) levels is associated with higher mortality in prevalent hemodialysis patients

BACKGROUND

The mortality of dialysis patients is 10- to 100-fold higher than in the general population. Baseline serum PTH levels, and more recently, changes in serum PTH levels (ΔPTH) over time, have been associated to mortality in dialysis patients.

METHODS

We explored the relationship between ΔPTH over 1 year with mortality over the next year in a prospective cohort of 115 prevalent hemodialysis patients from a single center that had median baseline iPTH levels within guideline recommendations.

RESULTS

Median baseline iPTH levels were 205 (116.5, 400) pg/ml. ΔiPTH between baseline and 1 year was 85.2 ± 57.1 pg/ml. During the second year of follow-up, 27 patients died. ΔiPTH was significantly higher in patients who survived (+157.30 ± 25.82 pg/ml) than in those who died (+39.03 ± 60.95 pg/ml), while baseline iPTH values were not significantly different. The highest mortality (48%) was observed in patients with a decrease in ΔiPTH (ΔiPTH quartile 1, negative ΔiPTH) and the lowest (12%) mortality in quartile 3 ΔiPTH (ΔiPTH increase 101-300 pg/ml). In a logistic regression model, ΔiPTH was associated with mortality with an odds ratio (OR) of 0.998 (95% CI 0.996-0999, p = 0.038). In multivariable analysis, mortality risk was 73% and 88% lower for patients with ΔiPTH 0-100 pg/ml and 101-300 pg/ml, respectively, than for those with a decrease in ΔiPTH. In patients with a decrease in ΔiPTH, the OR for death was 4.131 (1.515-11.27)(p = 0.006).

CONCLUSIONS

In prevalent hemodialysis patients with median baseline iPTH values within the guideline recommended range, a decrease in ΔiPTH was associated with higher mortality. Further studies are required to understand the mechanisms and therapeutic implications of this observation that challenges current clinical practice.

Mortality after Renal Allograft Failure and Return to Dialysis

INTRODUCTION

The outcomes of patients who fail their kidney transplant and return to dialysis (RTD) has not been investigated in a nationally representative sample. We hypothesized that variations in management of transplant chronic kidney disease stage 5 leading to kidney allograft failure (KAF) and RTD, such as access, nutrition, timing of dialysis, and anemia management predict long-term survival.

METHODS

We used an incident cohort of patients from the United States Renal Data System who initiated hemodialysis between January 1, 2003 and December 31, 2008, after KAF. We used Cox regression analysis for statistical associations, with mortality as the primary outcome.

RESULTS

We identified 5,077 RTD patients and followed them for a mean of 30.9 ± 22.6 months. Adjusting for all possible confounders at the time of RTD, the adjusted hazards ratio (AHR) for death was increased with lack of arteriovenous fistula at initiation of dialysis (AHR 1.22, 95% CI 1.02-1.46, p = 0.03), albumin <3.5 g/dL (AHR 1.33, 95% CI 1.18-1.49, p = 0.0001), and being underweight (AHR 1.30, 95% CI 1.07-1.58, p = 0.006). Hemoglobin <10 g/dL (AHR 0.96, 95% CI 0.86-1.06, p = 0.46), type of insurance, and zip code-based median household income were not associated with higher mortality. Glomerular filtration rate <10 mL/min/1.73 m2 at time of dialysis initiation (AHR 0.83, 95% CI 0.75-0.93, p = 0.001) was associated with reduction in mortality.

CONCLUSIONS

Excess mortality risk observed in patients starting dialysis after KAF is multifactorial, including nutritional issues and vascular access. Adequate preparation of patients with failing kidney transplants prior to resuming dialysis may improve outcomes.

Analysis of the kinetics of the parathyroid hormone, and of associated patient outcomes, in a cohort of haemodialysis patients

Background

Observational studies have recently associated a decrease in serum parathyroid hormone (PTH) level with a higher rate of mortality among hemodialysis (HD) patients. Decreases in PTH level can result from medical intervention (MPD) and surgical parathyroidectomy (PTX), or may occur spontaneously, usually associated with an underlying malnutrition-inflammation syndrome (SPD). The aim of our study was to prospectively identify the incidence of decreases in PTH level in a cohort of HD patients and the frequency distribution of the different causes (MPD, PTX and SPD), as well as to evaluate the survival outcomes for each PTH group (MPD, PTX and SPD) compared to patients who did not experience a PTH decrease over the first 36 months of the study (NPD).

Methods

The 197 patients receiving HD at our center in January 2010, and meeting our eligibility criteria, were enrolled in our prospective study, and were observed for a period of 60 months. A decrease in PTH level >50 % between two successive PTH measurements obtained within an interval <3 months was defined as a significant event. MPD referred to a decrease in PTH due to an increased oral calcium intake, increased dialysate calcium concentration (DCC), increased alfacalcidol use, or use of cinacalcet therapy. A surgical 7/8 PTX was performed in young patients or in patients in whom cinacalcet therapy failed. SPD referred to a decrease in PTH related to a medical or surgical event. Baseline characteristics among patients in each group (MPD, PTX, SPD, and NPD) were evaluated using Fisher’s exact test. The 60-month survival was evaluated using Kaplan-Meier and Cox multivariable proportional hazards models. Univariate and multivariate Cox analyzes were used identify variables with mortality. The relative risk of mortality was expressed as a hazard ratio (HR).

Results

The distribution of the 197 patients forming our four study groups was 34 % in the NPD group, 35 % in the SPD group, 25 % in the MSD group and 6 % in the PTX group. Among patients in the SPD group, the main acute comorbid conditions were peripheral vascular and cardiac complications, sepsis, fractures, and cancers with an increase in serum CRP level (from 14.3 ± 18 to 132 ± 90 mg/L) and a decrease in serum albumin (from 33 ± 4.5 to 28.6 ± 4 g/L). In the MPD group, the main therapeutic change was an increase in DCC, either independently or in association with cinacalcet therapy. The median survival rate among patients was 10 months for SPD, compared to 22 months among patients in the MPD group (p < 0.001). Using multivariable Cox model and taking the NPD group as reference, the risk of mortality was lower among patients in the MPD group (HR, 0.42[0.2-0.87] p = 0.01), with survival being comparable for the SPD and NPD groups (HR, 1.3 [0.75-2.2]). No mortality was observed in the PTX group.

Conclusion

The poor outcomes associated with SPD, related to acute comorbid conditions, should not lead to undertreat secondary hyperparathyroidism whose appropriate medical or surgical therapies are associated with better outcomes.

Serum phosphorus, cardiovascular and all-cause mortality in the general population: A meta-analysis

BACKGROUND

The association between elevated serum phosphorus concentration and cardiovascular or all-cause mortality yielded conflicting results.

OBJECTIVE

To assess the association between elevated serum phosphorus concentration and cardiovascular or all-cause mortality in the general population by conducting a meta-analysis.

METHODS

We systematically searched the Pubmed and Embase databases until March 2016 for the prospective studies investigating serum phosphorus concentration and cardiovascular or all-cause mortality in the general population. We pooled risk ratio (RR) and corresponding 95% confidence intervals (CI) for the highest versus the reference category of serum concentration of phosphorus.

RESULTS

Six prospective cohort studies involving 120,269 subjects were identified. When compared the highest with the reference concentration of serum phosphorus, the pooled RR of cardiovascular mortality and all-cause mortality were 1.36 (95% CI 1.07-1.72) and 1.35 for all-cause mortality (95% CI 1.15-1.58), respectively. Stratified analyses revealed that elevated serum phosphorus significantly increased all-cause mortality risk among men (RR 1.33; 95% CI 1.11-1.60), but not in women (RR 1.09; 95% CI 0.89-1.33).

CONCLUSIONS

Elevated serum phosphorus concentration is independently associated with excessive risk of cardiovascular and all-cause mortality in the general population without chronic kidney disease. Serum phosphorus on all-cause mortality risk appears to be pronounced in men but exhibits no clear effect on women. However, gender difference of elevated serum phosphorus on mortality risk should be verified by more prospective studies.

Update on Mineral and Bone Disorders in Chronic Kidney Disease

The inappropriate phosphorus retention observed in chronic kidney disease is central to the pathophysiology of mineral and bone disorders observed in these patients. Subsequent derangements in serum fibroblast growth factor 23, parathyroid hormone, and calcitriol concentrations play contributory roles. Therapeutic intervention involves dietary phosphorus restriction and intestinal phosphate binders in order to correct phosphorus retention and maintain normocalcemia. Additional therapies may be considered to normalize serum fibroblast growth factor 23 and parathyroid hormone.

The Relation Between Variability of Intact Parathyroid Hormone, Calcium, and Cardiac Mortality in Hemodialysis Patients

Chronic kidney disease-mineral and bone disorder (CKD-BMD) is a condition known to be associated with cardiovascular disease and mortality in hemodialysis (HD) patients. The relation between calcium (Ca), phosphorus (P), and intact parathyroid hormone (iPTH) variability in HD patients and cardiac mortality is unknown. The purpose of this study was to assess the relation between variability in these parameters and cardiac mortality. Baseline demographic and biochemical parameters of 218 HD patients together with Ca values corrected with albumin and P values measured on a monthly basis and iPTH levels measured at 3-monthly intervals were recorded over 2 years. Standard deviation (SD) and smoothness index (SI) for each parameter were calculated to assess Ca, P, and iPTH variability. The relations between all parameters and cardiac mortality were then analyzed. Cardiac mortality was observed in 38 patients in the 2-year study period. Nonsurviving patients' ages, systolic and diastolic blood pressure (DBP), high sensitivity C-reactive protein (HsCRP) levels, mean iPTH, and SD iPTH were significantly higher than those of surviving patients, while albumin levels, SI iPTH and SI Ca were significantly lower. Age, low albumin, high DBP, SI iPTH, and SI Ca were identified as independent predictors of cardiac mortality at multivariate analysis. Our study shows that Ca and iPTH variability affect cardiac mortality independently of mean and baseline values. When supported by further studies, the relation between Ca and iPTH variability and cardiac mortality in HD patients can lead to a new perspective in terms of prognosis and treatment planning.

Renal biomarkers for the prediction of cardiovascular disease

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is a well-known risk factor for cardiovascular disease (CVD). Renal biomarkers might be valuable in predicting CVD. Investigation of these biomarkers may uncover some of the poorly understood mechanisms that link renal and CVD as well as aid in the modification of disease and serve as a useful tool in diagnosing early disease and monitoring therapeutic responses. In this review we discuss the clinical utility of emerging and known renal biomarkers in predicting CVD.

RECENT FINDINGS

Prior to adopting a biomarker into routine clinical practice, evidence-based laboratory medicine requires optimal technical and analytical performance, which is a prerequisite to have confidence in the result. Furthermore, an ideal biomarker should have evidence of its utility in predicting clinical, therapeutic and other health outcomes as well as proving its organizational impact and cost-effectiveness. The renal biomarkers that have been associated with CVD include cystatin C as a better marker of glomerular filtration than creatinine, albuminuria, neutrophil gelatinase associated lipocalin, a marker of acute kidney injury, fibroblast growth factor-23 and parathyroid hormone. Only urine albumin has been adopted into routine clinical practice.

SUMMARY

Of all the renal biomarkers, only albumin is clearly associated with CVD. The other biomarkers are earlier in clinical development and the evidence base for their clinical utility needs to be expanded substantially before they can be adopted into routine practice.

Parathyroid hormone, cardiovascular and all-cause mortality: A meta-analysis

BACKGROUND

Inconsistent findings have reported on parathyroid hormone (PTH) concentration and cardiovascular or all-cause mortality.

OBJECTIVE

To investigate whether elevated PTH concentration was an independent predictor for cardiovascular or all-cause mortality in the general population by conducting a meta-analysis based on prospective studies.

METHOD

We searched Cochrane Library, Pubmed, and Embase databases up to June 2015. Only prospective studies evaluating serum PTH concentration and cardiovascular or all-cause mortality were included. Pooled adjust risk ratio (RR) and corresponding 95% confidence intervals (CI) were calculated for the highest vs. lowest PTH concentration.

RESULTS

Ten studies with 31,616 subjects were identified and analyzed. Compared the highest to the lowest PTH concentration, elevated serum PTH concentration increased the risk of all-cause mortality (RR 1.19; 95% CI 1.08-1.30) but not for cardiovascular mortality (RR 1.26; 95% CI 0.96-1.66). Subgroup analyses indicated that cardiovascular mortality risk appeared to be more pronounced among men (RR 1.68; 95% CI 1.05-2.67).

CONCLUSIONS

Elevated PTH concentration is an independent predictor of all-cause mortality. Elevated serum PTH concentration appears to increase risk of cardiovascular mortality among men.

Economic Evaluation of Cinacalcet in the United States: The EVOLVE Trial

BACKGROUND

Previous economic evaluations of cinacalcet in patients with secondary hyperparathyroidism (sHPT) relied on the combination of surrogate end points in clinical trials and epidemiologic studies.

OBJECTIVES

The objective was to conduct an economic evaluation of cinacalcet on the basis of the EValuation Of Cinacalcet HCl Therapy to Lower CardioVascular Events (EVOLVE) trial from a US payer perspective.

METHODS

We developed a semi-Markov model to assess the cost-effectiveness of cinacalcet in addition to conventional therapy, compared with conventional therapy alone, in patients with moderate-to-severe sHPT receiving hemodialysis. We used treatment effect estimates from the unadjusted intent-to-treat (ITT) analysis and prespecified covariate-adjusted ITT analysis as our main analyses. We assessed model sensitivity to variations in individual inputs and overall decision uncertainty through probabilistic sensitivity analyses.

RESULTS

The incremental cost-effectiveness ratio (ICER) for cinacalcet was $61,705 per life-year and $79,562 per quality-adjusted life-year (QALY) gained using the covariate-adjusted ITT analysis. Probabilistic sensitivity analysis suggested a 73.2% chance of the ICER being below a willingness-to-pay threshold of $100,000. Treatment effects from unadjusted ITT analysis yielded an ICER of $115,876 per QALY. The model was most sensitive to the treatment effect on mortality.

CONCLUSIONS

In the unadjusted ITT analysis, cinacalcet does not represent a cost- effective use of health care resources when applying a willingness-to-pay threshold of $100,000 per QALY. When using the covariate-adjusted ITT treatment effect, which represents the least biased estimate, however, cinacalcet is a cost-effective therapy for patients with moderate-to-severe sHPT on hemodialysis.

Approximation of Corrected Calcium Concentrations in Advanced Chronic Kidney Disease Patients with or without Dialysis Therapy

Background

The following calcium (Ca) correction formula (Payne) is conventionally used for serum Ca estimation: corrected total Ca (TCa) (mg/dl) = TCa (mg/dl) + [4 – albumin (g/dl)]; however, it is inapplicable to advanced chronic kidney disease (CKD) patients.

Methods

1,922 samples in CKD G4 + G5 patients and 341 samples in CKD G5D patients were collected. Levels of TCa (mg/day), ionized Ca²⁺ (iCa²⁺) (mmol/l) and other clinical parameters were measured. We assumed the corrected TCa to be equal to eight times the iCa²⁺ value (measured corrected TCa). We subsequently performed stepwise multiple linear regression analysis using the clinical parameters.

Results

The following formula was devised from multiple linear regression analysis. For CKD G4 + G5 patients: approximated corrected TCa (mg/dl) = TCa + 0.25 × (4 – albumin) + 4 × (7.4 – pH) + 0.1 × (6 – P) + 0.22. For CKD G5D patients: approximated corrected TCa (mg/dl) = TCa + 0.25 × (4 – albumin) + 0.1 × (6 – P) + 0.05 × (24 – HCO₃^-) + 0.35. Receiver operating characteristic analysis showed the high values of the area under the curve of approximated corrected TCa for the detection of measured corrected TCa ≥8.4 mg/dl and ≤10.4 mg/dl for each CKD sample. Both intraclass correlation coefficients for each CKD sample demonstrated superior agreement using the new formula compared to the previously reported formulas.

Conclusion

Compared to other formulas, the approximated corrected TCa values calculated from the new formula for patients with CKD G4 + G5 and CKD G5D demonstrates superior agreement with the measured corrected TCa.

Compliance with guidelines and predictors of mortality in hemodialysis. Learning from Serbia patients

OBJECTIVES

The aims of the study were to determine the percentage of patients on regular hemodialysis (HD) in Serbia failing to meet KDOQI guidelines targets and find out factors associated with the risk of time to death and the association between guidelines adherence and patient outcome.

METHODS

A cohort of 2153 patients on regular HD in 24 centers (55.7% of overall HD population) in Serbia were followed from January 2010 to December 2012. The percentage of patients failing to meet KDOQI guidelines targets of dialysis dose (Kt/V>1.2), hemoglobin (>110g/L), serum phosphorus (1.1-1.8mmol/L), calcium (2.1-2.4mmol/L) and iPTH (150-300pg/mL) was determined. Cox proportional hazards analysis was used to select variables significantly associated with the risk of time to death.

RESULTS

The patients were on regular HD for 5.3±5.3 years, dialyzed 11.8±1.9h/week. Kt/V<1.2 had 42.4% of patients, hemoglobin <110g/L had 66.1%, s-phosphorus <1.1mmol/L had 21.7% and >1.8mmol/L 28.6%, s-calcium <2.1mmol/L had 11.7% and >2.4mmol/L 25.3%, iPTH <150pg/mL had 40% and >300pg/mL 39.7% of patients. Using Cox model (adjustment for patient age, gender, duration of HD treatment) age, duration of HD treatment, hemoglobin, iPTH and diabetic nephropathy were selected as significant independent predictors of time to death. When targets of five examined parameters were included in Cox model, target for KtV, hemoglobin and iPTH were found to be significant independent predictors of time to death.

CONCLUSION

Substantial proportion of patients examined failed to meet KDOQI guidelines targets. The relative risk of time to death was associated with being outside the targets for Kt/V, hemoglobin and iPTH.

Achievement of guideline targets in elderly patients on hemodialysis: a multicenter study

OBJECTIVES

Advanced age is associated with shorter survival on dialysis. The aim of the present study was to compare the adherence with KDOQI guideline targets and the association between mortality and satisfying the guidelines targets between hemodialysis patients aged 65 years and over and those younger than 65 years.

METHODS

Data were collected using a questionnaire sent to all 46 HD centers in Serbia with totally 3868 HD patients. The 24 centers responded and sent the data on all patients aged 18 years or older that were on regular HD for more than 3 months (2153 patients, 1320 males, aged 18-90 years). Data are presented in two groups: a group of patients younger than 65 years (1438, 66.8 %) and a group of patients aged 65 years and over (715, 33.2 %). The percentage of patients whose values failed to meet the targets recommended by KDOQI Clinical Practice Guidelines was calculated for dialysis dose (spKt/V), hemoglobin, serum phosphorus, serum calcium and plasma iPTH (150-300 pg/mL). Patients were followed from enrollment until their death, kidney transplantation, departure from the center or the end of the study.

RESULTS

Elderly patients were more likely to have hypertension, significantly lower systolic and diastolic blood pressure and smaller dialysis vintage than younger patients. They were less frequently treated with high-flux membranes and hemodiafiltration and they had significantly lower number of dialysis hours per week and significantly lower interdialytic weight gain. They used ESA and phosphate binders less frequently than younger patients (p < 0.001 and p = 0.002). Older patients had similar Kt/V as younger ones but they had significantly more frequent Hb level outside the target range than younger patients. During the year follow-up period, by using a Cox proportional hazards model it has been confirmed that age, dialysis vintage, weekly dialysis time and target values for Kt/V were significant independent predictors of time to death for younger patients and gender, dialysis vintage and iPTH were independent predictor of time to death for older patients.

CONCLUSION

Despite less favorable dialysis prescription, older patients had similar Kt/V and less frequent deviations from the target values proposed by KDOQI for serum phosphorus and iPTH but more frequent deviation for Hb value as compared with younger patients. Risk factors for mortality differ between older and younger patients; out of five KDOQI targets, only Kt/V proved to be a significant risk factor for mortality for younger and iPTH for older patients.

Total, dietary, and supplemental calcium intake and mortality from all-causes, cardiovascular disease, and cancer: A meta-analysis of observational studies

AIMS

This systematic review and meta-analysis of observational studies was conducted to summarize the evidence on the association between calcium intake and mortality.

METHODS AND RESULTS

PubMed, Institute for Scientific Information (ISI) (Web of Science), SCOPUS, SciRUS, Google Scholar, and Excerpta Medica dataBASE (EMBASE) were searched to identify related articles published through May 2014. We found 22 articles that assessed the association between total, dietary, and supplementary intake with mortality from all-causes, cardiovascular disease (CVD), and cancer. Findings from this meta-analysis revealed no significant association between total and dietary calcium intake and mortality from all-causes, CVD, and cancer. Subgroup analysis by the duration of follow-up revealed a significant positive association between total calcium intake and CVD mortality for cohort studies with a mean follow-up duration of >10 years (relative risk (RR): 1.35; 95% confidence interval (CI): 1.09-1.68). A significant inverse association was seen between dietary calcium intake and all-cause (RR: 0.84; 95% CI: 0.70-1.00) and CVD mortality (RR: 0.88; 95% CI: 0.78-0.99) for studies with a mean follow-up duration of ≤10 years. Although supplemental calcium intake was not associated with CVD (RR: 0.95; 95% CI: 0.82-1.10) and cancer mortality (RR: 1.22; 95% CI: 0.81-1.84), it was inversely associated with the risk of all-cause mortality (RR: 0.91; 95% CI: 0.88-0.94).

CONCLUSIONS

We found a significant relationship between the total calcium intake and an increased risk of CVD mortality for studies with a long follow-up time and a significant protective association between dietary calcium intake and all-cause and CVD mortality for studies with a mean follow-up of ≤10 years. Supplemental calcium intake was associated with a decreased risk of all-cause mortality.

Effect Modifying Role of Serum Calcium on Mortality-Predictability of PTH and Alkaline Phosphatase in Hemodialysis Patients: An Investigation Using Data from the Taiwan Renal Registry Data System from 2005 to 2012

Predicting mortality in dialysis patients based on low intact parathyroid hormone levels is difficult, because aluminum intoxication, malnutrition, older age, race, diabetes, or peritoneal dialysis may influence these levels. We investigated the clinical implications of low parathyroid hormone levels in relation to the mortality of dialysis patients using sensitive, stratified, and adjusted models and a nationwide dialysis database. We analyzed data from 2005 to 2012 that were held on the Taiwan Renal Registry Data System, and 94,983 hemodialysis patients with valid data regarding their intact parathyroid levels were included in this study. The patient cohort was subdivided based on the intact parathyroid hormone and alkaline phosphatase levels. The mean hemodialysis duration within this cohort was 3.5 years. The mean (standard deviation) age was 62 (14) years. After adjusting for age, sex, diabetes, the hemodialysis duration, serum albumin levels, hematocrit levels, calcium levels, phosphate levels, and the hemodialysis treatment adequacy score, the single-pool Kt/V, the crude and adjusted all-cause mortality rates increased when alkaline phosphatase levels were higher or intact parathyroid hormone levels were lower. In general, at any given level of serum calcium or phosphate, patients with low intact parathyroid hormone levels had higher mortality rates than those with normal or high iPTH levels. At a given alkaline phosphatase level, the hazard ratio for all-cause mortality was 1.33 (p < 0.01, 95% confidence interval 1.27–1.39) in the group with intact parathyroid hormone levels < 150 pg/mL and serum calcium levels > 9.5 mg/dL, but in the group with intact parathyroid hormone levels > 300 pg/mL and serum calcium levels > 9.5 mg/dL, the hazard ratio was 0.92 (95% confidence interval 0.85–1.01). Hence, maintaining albumin-corrected high serum calcium levels at > 9.5 mg/dL may correlate with poor prognoses for patients with low intact parathyroid hormone levels.

Increased risk of all-cause mortality and renal graft loss in stable renal transplant recipients with hyperparathyroidism

BACKGROUND

Hyperparathyroidism is reported in 10% to 66% of renal transplant recipients (RTR). The influence of persisting hyperparathyroidism on long-term clinical outcomes in RTR has not been examined in a large prospective study.

METHODS

We investigated the association between baseline parathyroid hormone (PTH) levels and major cardiovascular events, renal graft loss, and all-cause mortality by Cox Proportional Hazard survival analyses in 1840 stable RTR derived from the Assessment of LEscol in Renal Transplantation trial. Patients were recruited in a mean of 5.1 years after transplantation, and follow-up time was 6 to 7 years.

RESULTS

Significant associations between PTH and all 3 outcomes were found in univariate analyses. When adjusting for a range of plausible confounders, including measures of renal function and serum mineral levels, PTH remained significantly associated with all-cause mortality (4% increased risk per 10 units; P=0.004), and with graft loss (6% increased risk per 10 units; P<0.001), but not with major cardiovascular events. Parathyroid hormone above the upper limit of normal (65 pg/mL) indicated a 46% (P=0.006) higher risk of death and an 85% higher risk of graft loss (P<0.001) compared with low/normal values.

CONCLUSIONS

Hyperparathyroidism is an independent, potentially remediable, risk factor for renal graft loss and all-cause mortality in RTR.

A prospective observational study of all-cause mortality in relation to serum 25-OH vitamin D3 and parathyroid hormone levels in patients with type 2 diabetes

BACKGROUND

Low levels of vitamin D have been related to increased mortality and morbidity in several non-diabetic studies. We aimed to prospectively study relationships between serum 25-OH vitamin D3 (vitamin D) and of serum parathyroid hormone (PTH) to total mortality in type 2 diabetes. We also aimed to compare the levels of these potential risk-factors in patients with and without diabetes.

METHODS

The main study design was prospective and observational. We used baseline data from 472 men and 245 women who participated in the "Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care" study. Patients were 55-66 years old at recruitment, and an age-matched non-diabetic sample of 129 individuals constituted controls for the baseline data. Carotid-femoral pulse-wave velocity (PWV) was measured with applanation-tonometry and carotid intima-media thickness (IMT) with ultrasound. Patients with diabetes were followed for all-cause mortality using the national Swedish Cause of Death Registry.

RESULTS

Levels of vitamin D were lower in patients with diabetes than in controls, also after correction for age and obesity, while PTH levels did not differ. Nine women and 24 men died during 6 years of median follow up of the final cohort (n = 698). Vitamin D levels were negatively related to all-cause mortality in men independently of age, PTH, HbA1c, waist circumference, 24-h systolic ambulatory-blood pressure (ABP) and serum-apoB (p = 0.049). This finding was also statistically significant when PWV and IMT were added to the analyses (p = 0.028) and was not affected statistically when medications were also included in the regression-analysis (p = 0.01). In the women with type 2 diabetes, levels of PTH were positively related with all-cause mortality in the corresponding calculations (p = 0.016 without PWV and IMT, p = 0.006 with PWV and IMT, p = 0.045 when also adding medications to the analysis), while levels of vitamin D was without statistical significance (p >0.9).

CONCLUSIONS

Serum vitamin D in men and serum PTH in women give prognostic information in terms of total-mortality that are independent of regular risk factors in addition to levels of ABP, IMT and PWV.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01049737.

Effects of cinacalcet on atherosclerotic and nonatherosclerotic cardiovascular events in patients receiving hemodialysis: the EValuation Of Cinacalcet HCl Therapy to Lower CardioVascular Events (EVOLVE) trial

Background

Premature cardiovascular disease limits the duration and quality of life on long‐term hemodialysis. The objective of this study was to define the frequency of fatal and nonfatal cardiovascular events attributable to atherosclerotic and nonatherosclerotic mechanisms, risk factors for these events, and the effects of cinacalcet, using adjudicated data collected during the EValuation of Cinacalcet HCl Therapy to Lower CardioVascular Events (EVOLVE) Trial.

Methods and Results

EVOLVE was a randomized, double‐blind, placebo‐controlled clinical trial that randomized 3883 hemodialysis patients with moderate to severe secondary hyperparathyroidism to cinacalcet or matched placebo for up to 64 months. For this post hoc analysis, the outcome measure was fatal and nonfatal cardiovascular events reflecting atherosclerotic and nonatherosclerotic cardiovascular diseases. During the trial, 1518 patients experienced an adjudicated cardiovascular event, including 958 attributable to nonatherosclerotic disease. Of 1421 deaths during the trial, 768 (54%) were due to cardiovascular disease. Sudden death was the most frequent fatal cardiovascular event, accounting for 24.5% of overall mortality. Combining fatal and nonfatal cardiovascular events, randomization to cinacalcet reduced the rates of sudden death and heart failure. Patients randomized to cinacalcet experienced fewer nonatherosclerotic cardiovascular events (adjusted relative hazard 0.84, 95% CI 0.74 to 0.96), while the effect of cinacalcet on atherosclerotic events did not reach statistical significance.

Conclusions

Accepting the limitations of post hoc analysis, any benefits of cinacalcet on cardiovascular disease in the context of hemodialysis may result from attenuation of nonatherosclerotic processes.

Clinical Trials Registration

Unique identifier: NCT00345839. URL: ClinicalTrials.gov.

Can serum levels of alkaline phosphatase and phosphate predict cardiovascular diseases and total mortality in individuals with preserved renal function? A systemic review and meta-analysis

BACKGROUND

It is demonstrated that elevated serum levels of alkaline phosphatase (ALP) and phosphate indicate a higher risks of cardiovascular disease (CVD) and total mortality in population with chronic kidney disease (CKD), but it remains unclear whether this association exists in people with normal or preserved renal function.

METHOD

Clinical trials were searched from Embase and PubMed from inception to 2013 December using the keywords "ALP", "phosphate", "CVD", "mortality" and so on, and finally 24 trials with a total of 147634 patients were included in this study. Dose-response and semi-parametric meta-analyses were performed.

RESULTS

A linear association of serum levels of ALP and phosphate with risks of coronary heart disease (CHD) events, CVD events and deaths was identified. The relative risk (RR) of ALP for CVD deaths was 1.02 (95% confidence interval [CI], 1.01-1.04). The RR of phosphate for CVD deaths and events was 1.05 (95% CI, 1.02-1.09) and 1.04 (95% CI: 1.03-1.06), respectively. A non-linear association of ALP and phosphate with total mortality was identified. Compared with the reference category of ALP and phosphate, the pooled RR of ALP for total mortality was 1.57 (95% CI, 1.27-1.95) for the high ALP group, while the RR of phosphate for total mortality was 1.33 (95% CI, 1.21-1.46) for the high phosphate group. It was observed in subgroup analysis that higher levels of serum ALP and phosphate seemed to indicate a higher mortality rate in diabetic patients and those having previous CVD. The higher total mortality rate was more obvious in the men and Asians with high ALP.

CONCLUSION

A non-linear relationship exists between serum levels of ALP and phosphate and risk of total mortality. There appears to be a positive association of serum levels of ALP/phosphate with total mortality in people with normal or preserved renal function, while the relationship between ALP and CVD is still ambiguous.

Parathyroid hormone and clinical outcome in kidney transplant patients with optimal transplant function

BACKGROUND

The aim of the study was to investigate whether serum levels of intact parathyroid hormone (iPTH) are associated with an increased risk of cardiovascular events, graft loss, or mortality in kidney transplant patients with optimal transplant function.

METHODS

From the Norwegian Renal Registry, we identified 522 patients who received a first kidney transplant from 2001 to 2008 with optimal transplant function defined as an estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m2, more than one yr after transplantation. Cox's proportional hazard models were used to assess the association between iPTH measured 10 wk after transplantation and the composite endpoint. The estimates were adjusted for age, gender, serum calcium, serum phosphate, diabetes mellitus, cardiovascular disease, and time on dialysis prior to transplantation.

RESULTS

Median follow-up time was 3.9 yr (interquartile range, IQR: 2.0-6.0 yr). Patients in the third iPTH quartile (9.3-14.4 pM) had the lowest risk for reaching the composite endpoint. Patients in the fourth iPTH quartile (>14.4 pM) had an increased risk compared to those in the third quartile (HR: 2.60, 95% CI: 1.10-6.16, p=0.03).

CONCLUSION

In patients with optimal transplant function, iPTH levels are associated with a clinical outcome consisting of cardiovascular events, graft loss, and all-cause mortality.