Are PTH serum levels predictive of coronary calcifications in haemodialysis patients?

Mineral and bone metabolism markers and mortality in diabetic patients on haemodialysis

BACKGROUND

Diabetic patients on haemodialysis have a higher risk of mortality than non-diabetic patients. The aim of this COSMOS (Current management of secondary hyperparathyroidism: a multicentre observational study) analysis was to assess whether bone and mineral laboratory values [calcium, phosphorus and parathyroid hormone (PTH)] contribute to this risk.

METHODS

COSMOS is a multicentre, open-cohort, 3-year prospective study, which includes 6797 patients from 227 randomly selected dialysis centres in 20 European countries. The association between mortality and calcium, phosphate or PTH was assessed using Cox proportional hazard regression models using both penalized splines smoothing and categorization according to KDIGO guidelines. The effect modification of the association between the relative risk of mortality and serum calcium, phosphate or PTH by diabetes was assessed.

RESULTS

There was a statistically significant effect modification of the association between the relative risk of mortality and serum PTH by diabetes (P = .011). The slope of the curve of the association between increasing values of PTH and relative risk of mortality was steeper for diabetic compared with non-diabetic patients, mainly for high levels of PTH. In addition, high serum PTH (>9 times the normal values) was significantly associated with a higher relative risk of mortality in diabetic patients but not in non-diabetic patients [1.53 (95% confidence interval 1.07-2.19) and 1.17 (95% confidence interval 0.91-1.52)]. No significant effect modification of the association between the relative risk of mortality and serum calcium or phosphate by diabetes was found (P = .2 and P = .059, respectively).

CONCLUSION

The results show a different association of PTH with the relative risk of mortality in diabetic and non-diabetic patients. These findings could have relevant implications for the diagnosis and treatment of chronic kidney disease-mineral and bone disorders.

Impact of Parathyroid Hormone Level on Intracoronary Calcification and Short- and Long-Term Outcomes in Dialysis Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND

Dialysis patients have strong intracoronary calcification, accelerated by secondary hyperparathyroidism as well as atherosclerosis. We evaluated the association of intact parathyroid hormone (iPTH) level with intracoronary calcification evaluated by intravascular ultrasound (IVUS), and its impact on both stent expansion after percutaneous coronary intervention (PCI) and long-term clinical outcomes, in dialysis patients with coronary artery disease (CAD).Methods and Results: A total of 116 patients on dialysis, who underwent PCI with IVUS guidance between March 2012 and December 2020, were enrolled. Patients were divided into 2 groups based on their median iPTH level. The degree of intracoronary calcification was evaluated by calcification score using grayscale IVUS in the target lesions. Preprocedural calcification scores were significantly higher in the high iPTH group compared with the low iPTH group (2.9±1.1 vs. 2.1±0.7, P<0.001). After PCI, the high iPTH group had a significantly lower stent expansion index (0.6±0.2 vs. 0.7±0.1, P<0.001) and stent symmetry index (0.5±0.1 vs. 0.7±0.1, P<0.001) compared with the low iPTH group. The incidence of major adverse cardiac or cerebrovascular events within 3 years was significantly higher in the high iPTH group (log-rank P<0.05).

CONCLUSIONS

High iPTH level is likely to increase intracoronary calcification, and cause inadequate stent expansion, which may be associated with increased risk of future adverse events in dialysis patients with CAD requiring PCI.

Osteoglycin as a Potential Biomarker of Mild Kidney Function Impairment in Type 2 Diabetes Patients

Osteoglycin (OGN) could be a biomarker of mild kidney function impairment in type 2 diabetes (T2D). Our study aimed to determine the association between serum OGN and impaired kidney function risk in T2D patients and to analyze its potential role as an estimator of kidney disturbances in this population. This cross-sectional study included 147 T2D patients (65 ± 8 years, 58.5% males), and 75 healthy controls (63 ± 10 years, 36% males). Circulating OGN levels were determined by ELISA. Linear regression modeling was performed to determine the variables influencing circulating OGN, and an ROC curve was plotted to assess the usefulness of OGN as an estimator of diabetic kidney disease risk. Circulating OGN was significantly increased in T2D patients compared to controls (18.41 (14.45–23.27) ng/mL vs. 8.74 (7.03–12.35) ng/mL; p < 0.001). We found a progressive increase in serum OGN according to the severity of kidney impairment in T2D patients (normal kidney function: 16.14 (12.13–20.48) ng/mL; mildly impaired kidney function: 19.15 (15.78–25.90) ng/mL; moderate impaired kidney function: 21.80 (15.06–29.22) ng/mL; p = 0.006). Circulating OGN was an independent estimator of mildly impaired kidney function risk in T2D patients. We suggest that serum OGN could act as an albuminuria-independent biomarker of incipient kidney dysfunction in T2D patients.

Relationship between parathyroid hormone and renin-angiotensin-aldosterone system in hemodialysis patients with secondary hyperparathyroidism

INTRODUCTION

Hyperparathyroidism (HPT) is associated with mortality and cardiovascular disease (CVD) in dialysis patients. However, its mechanism is still unclear. It is suspected that parathyroid hormone (PTH) is associated with the renin-angiotensin-aldosterone system (RAAS) as a possible mechanism. Thus, we examined their hormonal interaction in hemodialysis patients with secondary HPT.

MATERIALS AND METHODS

Seventeen hemodialysis patients with HPT were included. All patients underwent total parathyroidectomy (PTx). Serum intact PTH (iPTH), calcium and phosphate levels, plasma renin activity (PRA), and plasma aldosterone levels (ALD) were measured pre- and post-PTx.

RESULTS

Pre-serum iPTH tended to be correlated with pre-PRA and were significantly correlated with pre-ALD (pre-PRA: r = 0.44, p = 0.07, pre-ALD: r = 0.49, p < 0.05). With the reduction in serum iPTH after PTx, PRA and ALD significantly decreased after PTx. Additionally, the change in serum iPTH tended to be correlated with the changes in PRA and ALD (PRA; r = 0.46, p = 0.05, ALD; r = 0.45, p = 0.06).

CONCLUSION

Our results suggest that PTH could be interrelated with RAAS in hemodialysis patients with secondary HPT.

Serum indoxyl sulfate as a potential biomarker of aortic arterial stiffness in coronary artery disease

BACKGROUND AND AIMS

Indoxyl sulfate (IS), a dietary tryptophan metabolite, acts as a cardiotoxin and uremic toxin. High IS levels are associated with chronic kidney disease and cardiovascular diseases. This study investigated the association between serum IS levels and aortic arterial stiffness (AAS) in coronary artery disease (CAD) patients.

METHODS AND RESULTS

The carotid-femoral pulse wave velocity (cfPWV) was measured by the SphygmoCor system and patients with values of >10 m/s were classified in the AAS group. The baseline characteristics were recorded and measured (including biochemical and clinical data). Serum IS levels were determined using liquid chromatography-mass spectrometry. AAS occurred in 50 (34.7%) of 144 patients with CAD. They were older, had higher IS levels and percentages of diabetes, systolic blood pressure, blood urea nitrogen, and creatinine but lower estimated glomerular filtration rates. The IS level and older age significantly correlated with AAS [odds ratio (OR) = 3.834, p = 0.031; OR = 1.095, p = 0.002, respectively]. Furthermore, the serum IS level (β = 0.167, adjusted R² change: 0.026, p = 0.027) had a significant positive correlation with cfPWV.

CONCLUSIONS

Taken together, higher serum IS levels are potential independent biomarkers for AAS in patients with CAD. Therefore, early checking of serum IS levels may help prevent CAD progression and have clinical implications in the near future.

Mineral Bone Abnormalities and Vascular Calcifications

Vascular calcification (VC) is common in chronic kidney disease, increases in prevalence as patients progress to end-stage renal disease, and is significantly associated with mortality. VC is a complex and highly regulated process similar to bone formation whereby hydroxyapatite crystals deposit in the intimal or medial layer of arteries. Mineral bone abnormalities are common in chronic kidney disease; reduction in glomerular filtration rate and changes in vitamin D, parathyroid hormone, and fibroblast growth factor 23 result in the dysregulation of phosphorus and calcium metabolism. Cell culture studies, animal models, and observational and clinical studies all suggest this abnormal mineral metabolism plays a role in the initiation and progression of VC in kidney disease. This review will focus on these mineral bone abnormalities and how they may contribute to mechanisms that induce VC in kidney disease.

Relationship between serum osteoprotegerin and vascular calcifications in hemodialysis patients

BACKGROUND

Uremia is a vasculopathic process, and both cardiac calcification and vascular calcification seen from the early stages of chronic kidney disease. Osteoprotegerin could play a crucial role in atherosclerotic plaque formation, maturation and calcification. The goal of this study was to determine the relationship of serum osteoprotegerin with vascular calcification in patients with end stage kidney disease who were maintained on regular hemodialysis.

METHODS

Sixty clinically stable chronic renal failure patients undergoing regular hemodialysis were enrolled in this cross sectional study. Thirty patients (mean age 56.7 ± 10.5 years) with abdominal aortic calcification were selected by basal abdominal X-ray who underwent multi-slice computerized tomography scan to measure coronary artery calcification score; and thirty patients (mean age 56.5 ± 8.4 years) without abdominal aortic calcification. All patients were evaluated by serum calcium, phosphorus, albumin, lipid profile, intact parathyroid hormone (iPTH), serum creatinine, serum urea, serum uric acid, serum C-reactive protein, and hemoglobin. Serum osteoprotegerin samples were collected before dialysis and estimated by the ELISA kit.

RESULTS

Serum osteoprotegerin level was significantly higher in patients with vascular calcification than in those without calcifications. Serum osteoprotegerin correlated positively with serum phosphorus, calcium phosphorus product, alkaline phosphatase, iPTH, C-reactive protein, serum uric acid, low-density lipoprotein (LDL) and left ventricular mass index (LVMI) (p < 0.005), and negatively with hemoglobin, ejection fraction (p < 0.005) and HDL (p < 0.05).

CONCLUSIONS

These findings suggest that osteoprotegerin may be involved in the development of vascular calcification in hemodialysis patients.

Association between vascular calcification assessed by simple radiography and non-fatal cardiovascular events in hemodialysis patients

BACKGROUND

Vascular calcification (VC) is one of the factors associated with cardiovascular mortality in hemodialysis (HD) patients. Recommendations concerning screening for VC differ. Possible ability to prevent and reversibility of VC are major subjects on debate whether screening for VC could improve outcomes of renal patients. The objective of the study was to evaluate the significance of simple vascular calcification score (SVCS) based on plane radiographic films and to test its association with non-fatal cardiovascular events in patients on chronic HD.

METHODS

A study population consisted of 95 prevalent HD patients in the HD unit of Hospital of Lithuanian University of Health sciences Kaunas Clinics. Clinical data and laboratory tests information were collected from medical records. SVCS was evaluated as it is described by Adragao et al. After measurement of VC, HD patients were observed for novel non-fatal cardiovascular events.

RESULTS

Patients were divided into two groups: SVCS≥3 (57 patients [60%]) and <3 (38 patients [40%]). The Kaplan-Meier survival curves show a significant difference in non-fatal cardiovascular events in the group with SVCS≥3 vs. <3 group (26.3% vs. 7.8%; log rank 5,49; P=0.018). Multivariate Cox regression analysis confirmed a negative impact of VC, hyperphosphatemia, and lower ejection fraction on cardiovascular events. No statistically significant differences were observed comparing parameters of Ca-P metabolism disorders between groups with different SVCS. On separate analysis, the presence of VC in hands was also associated with higher rate of novel cardiovascular events (score 0 goup-5 events [10.6%] vs. score≥1 group-13 events [27%], log rank P=0.035).

CONCLUSION

VC assessed by simple and inexpensive radiological method was an independent predictor of novel non-fatal cardiovascular events in HD patients.

The role of bone biopsy for the diagnosis of renal osteodystrophy: a short overview and future perspectives

Chronic kidney disease (CKD) patients present specific bone and mineral metabolism disturbances, which account for important morbidity and mortality. The term renal osteodystrophy, classically used for the nomination of CKD-associated bone disorder, has been limited to the histologic description of bone lesions, requiring the use of bone biopsy. Biochemical markers and imaging tools do not adequately predict the complex bone changes that are observed in renal osteodystrophy. Parathyroid hormone, which is a universally used biomarker of bone turnover in clinical practice, lacks specificity and sensitivity. Therefore, tetracycline double-labelled transiliac bone biopsy, with bone histology and histomorphometric evaluation, remains the best clinical tool to discriminate bone turnover and to evaluate the other dimensions of renal osteodystrophy. This review will focus on the value of classic bone histomorphometric analysis of trabecular bone in CKD patients and unfold new perspectives of this diagnostic tool, including cortical bone evaluation and bone tissue immunohistochemistry.

The Risk of Peripheral Arterial Disease after Parathyroidectomy in Patients with End-Stage Renal Disease

Purpose

The changes of the risk of peripheral arterial disease (PAD) in patients with end-stage renal disease after parathyroidectomy are scant.

Methods

We used a nationwide health insurance claims database to select all dialysis-dependent patients with end-stage renal disease aged 18 years and older for the study population in 2000 to 2006. Of the patients with end-stage renal disease, we selected 947 patients who had undergone parathyroidectomy as the parathyroidectomy group and frequency matched 3746 patients with end-stage renal disease by sex, age, years since the disease diagnosis, and the year of index date as the non-parathyroidectomy group. We used a multivariate Cox proportional hazards regression analysis with the use of a robust sandwich covariance matrix estimate, accounting for the intra-cluster dependence of hospitals or clinics, to measure the risk of peripheral arterial disease for the parathyroidectomy group compared with the non-parathyroidectomy group after adjusting for sex, age, premium-based income, urbanization, and comorbidity.

Results

The mean post-op follow-up periods were 5.08 and 4.52 years for the parathyroidectomy and non-parathyroidectomy groups, respectively; the incidence density rate of PAD in the PTX group was 12.26 per 1000 person-years, significantly lower than the data in the non-PTX group (24.09 per 1000 person-years, adjusted HR = 0.66, 95% CI = 0.46–0.94).

Conclusion

Parathyroidectomy is associated with reduced risk of peripheral arterial disease in patients with end-stage renal disease complicated with severe secondary hyperparathyroidism.

Adynamic bone disease: from bone to vessels in chronic kidney disease

Adynamic bone disease (ABD) is a well-recognized clinical entity in the complex chronic kidney disease (CKD)-mineral and bone disorder. Although the combination of low intact parathyroid hormone (PTH) and low bone alkaline phosphatase levels may be suggestive of ABD, the gold standard for precise diagnosis is histomorphometric analysis of tetracycline double-labeled bone biopsies. ABD essentially is characterized by low bone turnover, low bone volume, normal mineralization, and markedly decreased cellularity with minimal or no fibrosis. ABD is increasing in prevalence relative to other forms of renal osteodystrophy, and is becoming the most frequent type of bone lesion in some series. ABD develops in situations with reduced osteoanabolic stimulation caused by oversuppression of PTH, multifactorial skeletal resistance to PTH actions in uremia, and/or dysregulation of Wnt signaling. All may contribute not only to bone disease but also to the early vascular calcification processes observed in CKD. Various risk factors have been linked to ABD, including calcium loading, ageing, diabetes, hypogonadism, parathyroidectomy, peritoneal dialysis, and antiresorptive therapies, among others. The relationship between low PTH level, ABD, increased risk fracture, and vascular calcifications may at least partially explain the association of ABD with increased mortality rates. To achieve optimal bone and cardiovascular health, attention should be focused not only on classic control of secondary hyperparathyroidism but also on prevention of ABD, especially in the steadily growing proportions of diabetic, white, and elderly patients. Overcoming the insufficient osteoanabolic stimulation in ABD is the ultimate treatment goal.

Reduced Stroke Risk After Parathyroidectomy in End-Stage Renal Disease: A 13-Year Population-Based Cohort Study

Research information on the risk of stroke in patients with dialysis-dependent end-stage renal disease (ESRD) who have undergone parathyroidectomy (PTX) is scant. We used a nationwide health insurance claims database to select all patients with dialysis-dependent ESRD age 18 years and older for the study population. Of the patients with ESRD, we selected 1083 patients who had undergone PTX between 1998 and 2006 as the PTX group and frequency-matched 1083 patients with ESRD by sex, age, years since the disease diagnosis, and the year of undergoing PTX as the non-PTX group. We used a multivariate Cox proportional hazards regression analysis to measure the risk of stroke for the PTX group compared with the non-PTX group after adjusting for sex, age, premium-based income, urbanization, and comorbidity. The mean follow-up periods were 6.08 and 5.38 years for the PTX and non-PTX groups, respectively. After adjusting for previously mentioned variables, significant risk reductions of stroke (adjusted hazard ratio = 0.57, 95% confidence interval = 0.41-0.79), particularly those of hemorrhagic stroke (adjusted hazard ratio = 0.34, 95% confidence interval = 0.20-0.57), with PTX were observed. Chronologically, the risk of stroke in the PTX group decreased in the second year after PTX and persisted for >3 years. PTX reduces the risk of stroke, particularly that of hemorrhagic stroke, in patients with dialysis-dependent ESRD. Other factors for risk reduction include sex (females), an age <65 years, and the presence of comorbidity.

Evaluating targets and costs of treatment for secondary hyperparathyroidism in incident dialysis patients: the FARO-2 study

Background

The aim of this analysis was to estimate biochemical parameters and the costs of treatment of secondary hyperparathyroidism (SHPT) in a subpopulation of the FARO-2 study.

Methods

The FARO-2 observational study aimed at evaluating the patterns of treatment for SHPT in naïve hemodialysis patients. Data related to pharmacological treatments and biochemical parameters (parathyroid hormone [PTH], calcium, phosphate) were recorded at entry to hemodialysis (baseline) and 6 months later (second survey). The analysis was performed from the Italian National Health Service perspective.

Results

Two prominent treatment groups were identified, ie, one on oral calcitriol (n=105) and the other on intravenous paricalcitol (n=33); the intravenous calcitriol and intravenous paricalcitol + cinacalcet combination groups were not analyzed due to low patient numbers. At baseline, serum PTH levels were significantly higher in the intravenous paricalcitol group (P<0.0001). At the second survey, the intravenous paricalcitol group showed a higher percentage of patients at target for PTH than in the oral calcitriol group without changing the percentage of patients at target for phosphate. Moreover, between baseline and the second survey, intravenous paricalcitol significantly increased both the percentage of patients at target for PTH (P=0.033) and the percentage of patients at target for the combined endpoint PTH, calcium, and phosphate (P=0.001). The per-patient weekly pharmaceutical costs related to SHPT treatment, erythropoietin-stimulating agents and phosphate binders accounted for 186.32€ and 219.94€ at baseline for oral calcitriol and intravenous paricalcitol, respectively, while after 6 months, the costs were 180.51€ and 198.79€, respectively. Either at the beginning of dialysis or 6 months later, the total cost of SHPT treatment was not significantly lower in the oral calcitriol group compared with the intravenous paricalcitol group, with a difference among groups that decreased by 46% between the two observations. The cost of erythropoietin stimulating agents at the second survey was lower (−22%) in the intravenous paricalcitol group than in the oral calcitriol group (132.13€ versus 168.36€, respectively).

Conclusion

Intravenous paricalcitol significantly increased the percentage of patients at target for the combined endpoint of PTH, calcium, and phosphate (P=0.001). The total cost of treatment for the patients treated with intravenous paricalcitol 6 months after entry to dialysis was not significantly higher than the cost for patients treated with oral calcitriol.

Vascular calcification: from pathophysiology to biomarkers

The link between vascular calcification (VC) and increased mortality is now well established. Over time, as clinical importance of this phenomenon has begun to be fully considered, scientists have highlighted more and more physiopathological mechanisms and signaling pathways that underlie VC. Several conditions such as diabetes, dyslipidemia and renal diseases are undoubtedly identified as predisposing factors. But even if the process is better understood, many questions still remain unanswered. This review briefly develops the various theories that attempt to explain mineralization genesis. Nonetheless, the main purpose of the article is to provide a profile of the various existing biomarkers of VC. Indeed, in the past years, a lot of inhibitors and promoters, which form a dense and interconnected network, were identified. Given importance to assess and control mineralization process, a focusing on accumulated knowledge of each marker seemed to be necessary. Therefore, we tried to define their respective role in the physiopathology and how they can contribute to calcification risk assessment. Among these, Klotho/fibroblast growth factor-23, fetuin-A, Matrix Gla protein, Bone morphogenetic protein-2, osteoprotegerin, osteopontin, osteonectin, osteocalcin, pyrophosphate and sclerostin are specifically discussed.

Parathyroidectomy improves survival in patients with severe hyperparathyroidism: a comparative study

Background and objectives

Secondary hyperparathyroidism (SHPT) in CKD is associated with an increased risk for mortality, but definitive data showing that parathormone control decreases mortality is still lacking. This study aimed to compare the mortality of patients with severe SHPT submitted to parathyroidectomy(PTX) with those who did not have access to surgery.

Methods

This is a retrospective study in a cohort of 251 CKD patients with severe SHPT who were referred to a CKD-MBD Center for PTX from 2005 until 2012.

Results

Most of our patients had indication of PTX, but only 49% of them had access to this surgical procedure. After a mean follow-up of 23 months, 72 patients had died. Non-survivors were older; more often had diabetes, lower serum 25 vitamin D and mostly had not been submitted to surgery. The relative risk of death was lower in the PTX patients (0.428; 95% CI, 0.28 to 0.67; p<0.0001). After adjustments, mortality risk was dependent on age (1.04; 95% CI, 1.01 to 1.07; p = 0.002), 25 vitamin D (0.43; 95% CI, 0.24 to 0.81; p = 0.006) and no access to PTX (4.13; 95% CI, 2.16 to 7.88; p<0.0001). Results remained the same in a second model using the PTX date as the study start date for the PTX group.

Conclusions

Our data confirms the benefit of PTX on mortality in patients with severe SHPT. The high mortality encountered in our population is significant and urges the need to better treat these patients.

Impact of mineral and bone disorder on healthcare resource use and associated costs in the European Fresenius medical care dialysis population: a retrospective cohort study

Background

Secondary hyperparathyroidism (SHPT) is associated with mortality in patients with chronic kidney disease (CKD), but the economic consequences of SHPT have not been adequately studied in the European population. We assessed the relationship between SHPT parameters (intact parathyroid hormone [iPTH], calcium, and phosphate) and hospitalisations, medication use, and associated costs among CKD patients in Europe.

Methods

The analysis of this retrospective cohort study used records of randomly selected patients who underwent haemodialysis between January 1, 2005 and December 31, 2006 at participating European Fresenius Medical Care facilities in 10 countries. Patients had ≥ 1 iPTH value recorded, and ≥ 1 month of follow-up after a 3-month baseline period during which SHPT parameters were assessed. Time at risk was post-baseline until death, successful renal transplantation, loss to follow-up, or the end of follow-up. Outcomes included cost per patient-month, rates of hospitalisations (cardiovascular disease [CVD], fractures, and parathyroidectomy [PTX]), and use of SHPT-, diabetes-, and CVD-related medications. National costs were applied to hospitalisations and medication use. Generalised linear models compared costs across strata of iPTH, total calcium, and phosphate, adjusting for baseline covariates.

Results

There were 6369 patients included in the analysis. Mean ± SD person-time at risk was 13.1 ± 6.4 months. Patients with iPTH > 600 pg/mL had a higher hospitalisation rate than those with lower iPTH. Hospitalisation rates varied little across calcium and phosphate levels. SHPT-related medication use varied with iPTH, calcium, and phosphate. After adjusting for demographic and clinical variables, patients with baseline iPTH > 600 pg/mL had 41% (95% CI: 25%, 59%) higher monthly total healthcare costs compared with those with iPTH in the K/DOQI target range (150–300 pg/mL). Patients with baseline phosphate and total calcium levels above target ranges (1.13–1.78 mmol/L and 2.10–2.37 mmol/L, respectively) had 38% (95% CI: 27%, 50%) and 8% (95% CI: 0%, 17%) higher adjusted monthly costs, respectively. Adjusted costs were 25% (95% CI: 18%, 32%) lower among patients with baseline phosphate levels below the target range. Results were consistent in sensitivity analyses.

Conclusions

These data suggest that elevated SHPT parameters increase the economic burden of CKD in Europe.

Improved long-term survival of dialysis patients after near-total parathyroidectomy

BACKGROUND

Severe secondary hyperparathyroidism, which is associated with life-threatening complications, can develop in dialysis-dependent end-stage renal disease patients. The aim of this study was to compare short- and long-term mortality in dialysis patients who underwent near-total parathyroidectomy (NTPTX) and matched nonoperated controls.

STUDY DESIGN

We identified 150 dialysis patients who underwent NTPTX (1993-2009) at our institution and compared them with 1,044 nonoperated control patients identified in the US Renal Data System registry, matched for age, sex, race, diabetes as cause of kidney failure, years on dialysis, and dialysis modality. Survival outcomes were estimated using multivariable Cox proportional hazards models with stratification on the matching sets, adjusted for cardiovascular comorbidities, smoking, inability to ambulate/transfer, and payor status.

RESULTS

During a follow-up of a mean of 3.6 years (range 0.1 month to 16.4 years), NTPTX patients had a significant reduction in the long-term risk of all-cause death (hazard ratio = 0.68; 95% CI, 0.52-0.89; p = 0.006) compared with controls. Thirty-day mortality rates for NTPTX patients and controls were 246 vs 105 per 1,000 person-years (p = 0.21). In adjusted analyses, NTPTX patients had a 37% reduced risk of all-cause death and a 33% reduced risk of cardiovascular death compared with controls. A durable reduction in mean parathyroid hormone was observed after NTPTX; from 1,776 ± 1,416.6 pg/mL to 301 ± 285.7 pg/mL (p < 0.0001).

CONCLUSIONS

In our center, NTPTX in dialysis patients was associated with a significant reduction in long-term risk of death compared with matched control patients, without a significantly increased short-term risk.

The IMPACT (Incident Management of Patients, Actions Centered on Treatment) program: a quality improvement approach for caring for patients initiating long-term hemodialysis

BACKGROUND

Patients beginning dialysis therapy are at risk of death and illness. The IMPACT (Incident Management of Patients, Actions Centered on Treatment) quality improvement program was developed to improve incident hemodialysis patient outcomes through standardized care.

STUDY DESIGN

Quality improvement report.

SETTING & PARTICIPANTS

Patients who started hemodialysis therapy between September 2007 and December 2008 at DaVita facilities using the IMPACT program (n = 1,212) constituted the intervention group. Propensity score-matched patients who initiated hemodialysis therapy in the same interval at DaVita facilities not using the IMPACT program (n = 2,424) made up the control group.

QUALITY IMPROVEMENT PLAN

IMPACT intervention included a structured intake process and monitoring reports; patient enrollment in a 90-day patient education program and 90-day patient management pathway.

OUTCOMES

Mean dialysis adequacy (Kt/V), hemoglobin and albumin levels, percentage of patients using preferred vascular access (arteriovenous fistula or graft), and mortality at each quarter.

RESULTS

Compared with the non-IMPACT group, the IMPACT group was associated with a higher proportion of patients dialyzing with a preferred access at 90 days (0.50 [95% CI, 0.47-0.53] vs 0.47 [95% CI, 0.45-0.49]; P = 0.1) and 360 days (0.63 [95% CI, 0.61-0.66] vs 0.48 [95% CI, 0.46-0.50]; P < 0.001) and a lower mortality rate at 90 days (24.8 [95% CI, 19.0-30.7] vs 31.9 [95% CI, 27.1-36.6] deaths/100 patient-years; P = 0.08) and 360 days (17.8 [95% CI, 15.2-20.4] vs 25.1 [95% CI, 20.7-25.2] deaths/100 patient-years; P = 0.01).

LIMITATIONS

The study does not determine the care processes responsible for the improved outcomes.

CONCLUSIONS

Intense management of incident dialysis patients with the IMPACT quality improvement program was associated with significantly decreased first-year mortality. Focused attention to the care of incident patients is an important part of a dialysis program.

Cinacalcet: will it play a role in reducing cardiovascular events?

Secondary hyperparathyroidism is a common complication of chronic kidney disease and it is associated with high morbidity and mortality. It is characterized by high parathyroid hormone levels and bone turnover leading to bone pain, deformity and fragility. Furthermore, secondary hyperparathyroidism adversely affects the cardiovascular system and has been associated with cardiovascular calcification and cardiomyopathy. Cinacalcet, a type II calcimimetic, is an effective and well-tolerated oral therapy for the management of secondary hyperparathyroidism. It is an allosteric activator of the calcium-sensing receptor enhancing sensitivity of parathyroid cells to extracellular calcium, which leads to inhibition of parathyroid hormone secretion. The calcium-sensing receptor expression in cardiomyocytes, endothelial cells and vascular smooth muscle cells raises the possibility that this receptor may be implicated in the pathophysiology of cardiovascular disease and constitute a potential therapeutic target. This article reviews the role of the calcimimetic agent cinacalcet in the prevention and progression of cardiovascular calcification and uremic cardiomyopathy in the chronic kidney disease setting.

Calciphylaxis presenting in early chronic kidney disease with mixed hyperparathyroidism

Calciphylaxis is a disabling and life-threatening complication that primarily affects patients who are dialysis dependent. Reports have grown in the literature of cases occurring in those who have advanced chronic kidney disease (pre-end-stage renal disease) or in the setting of transplantation. There are also a few reports of cases occurring in those without any form of chronic kidney disease but with primary hyperparathyroidism. This disease entity is characterized by calcification, intimal hypertrophy, and thrombosis of small vessels that result in necrotizing, nonhealing ulcers – many of which are life threatening. Although several strategies aimed at treating and preventing this affliction have been reported in the literature, the outcome for most patients with calciphylaxis remains quite poor. We describe a patient with comparatively early stage-3 chronic kidney disease who developed calciphylaxis in the setting of both primary and secondary hyperparathyroidism. Predictably, after subtotal parathyroidectomy, her wounds did not completely heal and her biochemical markers of hyperparathyroidism did not completely normalize until her underlying secondary hyperparathyroidism was treated medically. It was only after initiating cinacalcet that the patient experienced complete wound healing and resolution of her calciphylaxis. It also supports other authors’ findings that cinacalcet may be an important adjunct in the treatment of calciphylaxis.

Vascular calcifications and renal osteodystrophy in chronic hemodialysis patients: what is the relationship between them?

INTRODUCTION

Vascular calcifications (VCs) and renal osteodystrophy (ROD) are frequently seen together and represent the major causes of morbidity and mortality in hemodialysis (HD) patients. Some studies suggest a pathogenic link between them, but there is no consensus as yet regarding this issue. The main objective of our study was to establish whether there is any relation between VCs and ROD in our HD patients. We evaluated the prevalence of VCs and ROD and the relationship between VCs and some clinical and biochemical characteristics of HD patients.

METHODS

We examined radiological signs of VCs and ROD on hands and pelvis bone radiographs in 81 chronic HD patients, and we calculated a VC score on this basis.

RESULTS

We found a significant relation between radiological signs of ROD and those of VC (P = 0.019). The patients with ROD had a higher mean VC score (P = 0.02). By linear regression, the VC score correlated directly with serum calcium (Ca), phosphorus (P), intact parathyroid hormone (iPTH) and CaxP product and inversely with serum albumin. The logistic regression model revealed that ROD, male gender and treatment with calcium salts were predictive of VCs development. There were no associations between VCs and age, HD vintage, diabetes, dialysate Ca concentration, vitamin D treatment, spKt/V, URR and C-reactive protein (CRP) levels.

CONCLUSION

There seems to be a pathogenetic link between bone and artery diseases in chronic HD patients. Both VCs and ROD have a high prevalence. ROD, male gender and treatment with calcium salts are risk factors for VCs.

Tight relations between coronary calcification and atherosclerotic lesions in the carotid artery in chronic dialysis patients

AIM

Both vascular calcification and atherosclerosis are highly prevalent in patients with end-stage renal disease (ESRD) and have been associated with increased cardiovascular morbidity. Because those two phenomena might be only coincidentally related in chronic haemodialysis (HD) patients, in this study, coronary artery calcification (CAC), common carotid artery intima media thickness (CCA-IMT) and thickness of atherosclerotic plaques in the carotid artery were simultaneously measured.

METHODS

In a cross-sectional study of 47 HD patients (31 male, mean age 56.8 +/- 11.4 years, and 16 female, mean age 56.0 +/- 7.5 years) without history of major cardiovascular complications. CCA-IMT and presence and thickness of atherosclerotic plaques were measured with ultrasound and CAC with multidetector computed tomography.

RESULTS

The CAC were present in 70.2% of patients. The mean CAC was 1055 +/- 232, the mean CCA-IMT was 0.96 +/- 0.21. The atherosclerotic plaques in the common carotid arteries were visualized in 38 patients (80.1%), the mean thickness of the atherosclerotic plaque was 1.61 +/- 0.8 mm. We found a significant positive correlation between CAC and CCA-IMT (r = 0.70, P < 0.001). The thickness of atherosclerosis plaque positively correlated with CAC as well as with CCA-IMT (r = 0.60, P < 0.001 and r = 0.7, P < 0.003, respectively).

CONCLUSION

The study revealed close relationships between CAC, intima media thickness and the thickness of atherosclerotic plaques in dialysis patients. It may indicate that both vascular calcification and atherosclerotic lesions frequently coexist in patients with ESRD and that the intima media thickness could serve as a surrogate marker of vascular calcification.

Low iPTH can predict vascular and coronary calcifications in patients undergoing peritoneal dialysis

BACKGROUND

There is substantial evidence that low levels of serum intact parathyroid hormone (iPTH) are associated with vascular calcium deposition and subsequent increased cardiovascular risk in chronic kidney disease patients. The purpose of this study was to determine the relationship between the serum iPTH level, and vascular and coronary artery calcifications (VCs, CACs) and arterial stiffness in peritoneal dialysis (PD) patients.

METHODS

In this cross-sectional study, 93 PD patients were included. VCs, CACs and arterial stiffness were measured by simple X-rays of the hands and pelvis, multi-slice coronary CT and brachial-ankle pulse wave velocity (BaPWV).

RESULTS

Patients were divided into 3 groups according to iPTH levels. The prevalence of severe VCs (VC score ≥ 3) was highest in the low iPTH group (<150 pg/ml). In multivariate analysis, the presence of diabetes mellitus and a low iPTH were shown to be significant risk factors for severe VCs. In addition, a simple VC score of ≥ 1 was a significant variable for predicting severe CACs (CAC score ≥ 400).

CONCLUSION

Low iPTH and the presence of diabetes mellitus are thought to be independent risk factors for predicting VCs. VCs determined by simple X-ray can further predict the coexistence of CACs that ultimately might contribute to increased cardiovascular risk in PD patients.

Risk factors of one year increment of coronary calcifications and survival in hemodialysis patients

Background

Heart and coronary calcifications in hemodialysis patients are of very common occurrence and linked to cardiovascular events and mortality. Several studies have been published with similar results. Most of them were mainly cross-sectional and some of the prospective protocols were aimed to evaluate the results of the control of altered biochemical parameters of mineral disturbances with special regard to serum calcium, phosphate and CaxP with the use of calcium containing and calcium free phosphate chelating agents. The aim of the present study was to evaluate in hemodialysis patients classic and some non classic risk factors as predictors of calcification changes after one year and to evaluate the impact of progression on survival.

Methods

81 patients on hemodialysis were studied, with a wide age range and HD vintage. Several classic parameters and some less classic risk factors were studied like fetuin-A, CRP, 25-OHD and leptin. Calcifications, as Agatston scores, were evaluated with Multislice CT basally and after 12-18 months.

Results

Coronary artery calcifications were observed in 71 of 81 patients. Non parametric correlations between Agatston scores and Age, HD Age, PTH and CRP were significant. Delta increments of Agatston scores correlated also with serum calcium, CaxP, Fetuin-A, triglycerides and serum albumin. Logistic regression analysis showed Age, PTH and serum calcium as important predictors of Delta Agatston scores. LN transformation of the not normally distributed variables restricted the significant correlations to Age, BMI and CRP. Considering the Delta Agatston scores as dependent, significant predictors were Age, PTH and HDL. A strong association was found between basal calcification scores and Delta increment at one year. By logistic analysis, the one year increments in Agatston scores were found to be predictors of mortality. Diabetic and hypertensive patients have significantly higher Delta scores.

Conclusions

Progression of calcification is of common occurrence, with special regard to elevated basal scores, and is predictive of survival. Higher predictive value of survival is linked to the one year increment of calcification scores. Some classic and non classic risk factors play an important role in progression. Some of them could be controlled with appropriate management with possible improvement of mortality.

Brachial-ankle pulse wave velocity predicts silent cerebrovascular diseases in patients with end-stage renal diseases

AIM

Cerebrovascular disease (CVD) is a major determinant of the prognosis in end-stage renal diseases (ESRD). The purpose of this study was to examine whether factors associated with arterial stiffness contributed to the development of CVD in patients with ESRD.

METHODS

CVD (lacunes and carotid/intracranial artery stenosis) was evaluated with brain magnetic resonance imaging (MRI), and carotid/intracranial artery magnetic resonance angiography (MRA) in 44 pre-dialytic patients. The severity of CVD was evaluated by the number of lacunes and the degree of stenosis, respectively. The association between CVD and atherosclerotic parameters was evaluated.

RESULTS

Patients with severe lacunes (n=18) manifested older age, lower diastolic blood pressure, serum creatinine and albumin, and higher CRP and serum calcium than those with absent-moderate lacunes (n=26). When assessed by multivariate analysis, only baPWV was adopted as an independent risk factor for severe lacunes. Furthermore, baPWV and i-PTH were associated with the severity of carotid/intracranial artery stenosis, both of which were independent of other risk factors, including age and diabetes.

CONCLUSIONS

Arterial stiffness may constitute a novel determinant predicting the severity of CVD in pre-dialytic patients besides classical risk factors.

Progression of coronary artery calcification in renal transplantation and the role of secondary hyperparathyroidism and inflammation

BACKGROUND AND OBJECTIVES

Transplantation should favorably affect coronary calcification (CAC) progression in dialysis; however, changes in CAC score in the individual patient are not reliably evaluated.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

The authors used special tables of reproducibility limits for each score level to study, by multislice computed tomography and biochemistries, the 2-year changes in CAC in 41 transplant patients (age 48 +/- 13 yr, 25 men, dialysis vintage 4.8 +/- 4.3 yr, underwent transplant 6.2 +/- 5.5 yr prior). Thirty balanced dialysis patients served as controls.

RESULTS

In the study group, Agatston score was stable, and C-reactive protein decreased, whereas fetuin and osteoprotegerin increased. In the control group, Agatston score increased, parathyroid hormone and phosphate decreased, and inflammation markers were persistently twice as high as in the study group. With regard to individual changes, 12.2% transplant patients worsened, compared with 56.6% of patients in dialysis (P < 0.0001). Patients without calcification at entry showed slower progression in transplantation (8.3%) than in dialysis (44.4%; P < 0.034), and the difference was similar to that observed in cases with CAC (17.6% versus 61.9%; P < 0.007). Discriminant analysis indicated parathyroid hormone, the modality of therapy (dialysis or transplantation), and erythrocyte sedimentation rate as the variables most associated with worsening.

CONCLUSIONS

Renal transplantation lowers but does not halt CAC progression. Inflammation and hyperparathyroidism are associated with progression in the populations studied.

Calcimimetics, parathyroid hormone, and vascular calcification in chronic kidney disease

Vascular calcification (VC) occurs frequently in chronic kidney disease, contributing to cardiovascular mortality. Numerous risk factors have been identified, including renal osteodystrophy and bone turnover, with low turnover as a main determinant. Other reports support high turnover as a factor in VC. Calcimimetics, which lower serum parathyroid hormone, and parathyroidectomy each prevented VC induced by five-sixths nephrectomy in rats. These results favor increased bone turnover due to hyperparathyroidism, instead of low turnover, as a factor in VC in uremia.

Peripheral vascular calcification in long-haemodialysis patients: associated factors and survival consequences

BACKGROUND

Vascular calcifications (VCs) are frequently observed in chronic kidney disease (CKD) and haemodialysis (HD) patients. They have been associated with numerous factors, particularly hyperphosphataemia, excess calcium load, hypertension and increased mortality rate. The purpose of this study is to measure VCs in long-HD patients with good blood pressure and phosphate control, with the occasional use of sevelamer, using a plain radiological score to identify the associated factors and effects on the 1-year survival rate.

METHODS

We studied HD patients from one centre using a semi-quantitative score ranging from 0 to 3 according to the severity and extent of VCs. The following patients' characteristics were compared according to their VC scores: medical history, treatments, blood pressure, standard biological data, fibroblast growth factor (FGF) 23, osteoprotegerin (OPG), whole PTH, beta-crosslaps, bone alkaline phosphatases and bone mineral density scores. One-year survival analyses were also performed.

RESULTS

Among the 250 HD patients of the centre, 161 were studied; the mean age was 67.2 +/- 13 years, 45% of the subjects were females, 35% were diabetics, and they had been on dialysis for between 1-486 months (median: 45 months) with a 3 x 5-3 x 8 h dialysis schedule using 1.5 mmol/l dialysate calcium and providing a mean 2.25 +/- 0.5 Kt/V. Only 17% of the patients were free from VCs and 11% had severe VCs. The factors associated with VCs were classified into 'classic' (age, diabetes, male gender, tobacco use, inflammation, more frequent warfarin treatment and peripheral vascular and cardiac diseases) and 'non-traditional' (higher FGF-23 and OPG serum levels, low albumin serum levels and low alfacalcidol and CaCO(3) use). In logistic regression, only age, diabetes and FGF-23 serum levels were associated with VC scores of 2 and 3. The patients with a score of 3 had a higher 1-year mortality rate (RR 2.1; P = 0.01) as compared to patients with a 0 score.

CONCLUSION

A plain radiological score showed the high prevalence (83%) of VCs in HD patients in spite of a long and intensive dialysis strategy and adherence to guidelines. The main associated factors were classic factors such as ageing and diabetes. No relationship was found with blood pressure and phosphataemia that remained well controlled in long dialysis; the association with FGF-23 serum levels may aggregate some non-traditional risk factors. The harmful effects of VCs on survival require their systematic assessment and optimization of the potentially modifiable associated factors in CKD and HD patients.