Low parathyroid hormone status induced by high dialysate calcium is an independent risk factor for cardiovascular death in hemodialysis patients

Misdiagnosis of chronic kidney disease and parathyroid hormone testing during the past 16 years

Chronic kidney disease (CKD) is a prevalent pathological condition worldwide. Parathyroid hormone (PTH) is an important index related to bone metabolism in CKD patients and has not received enough attention. This study was performed to investigate the incidence and diagnostic rate of CKDin hospital as well as PTH testing and treatment for secondary hyperparathyroidism (SHPT) in patients with stage 3 to 5 CKD. The data of patients who visited Zhejiang Provincial People's Hospital from February 2006 to April 2022 were retrieved from the hospital database. All data were divided into three subgroups using PTH testing and SHPT treatment as major comparative indicators for analysis. The data were then analyzed for overall PTH testing, CKD incidence, and diagnostic rate. Among 5,301,391 patients, the incidence of CKD was 13.14%. The missed diagnosis rate for CKD was 65.76%. The total PTH testing rate was 1.22%, of which 15.37% of PTH testing was performed in patients with stage 3 to 5 CKD. The overall diagnosis rate of SHPT in patients with stage 3 to 5 CKD was 31.0%. The prophylactic medication rate was 7.4%, and the rate of post-diagnostic drug therapy was 22.2% in patients who underwent SHPT treatment. The high misdiagnosis rate and low PTH testing rate of CKD requires prompt attention from clinicians. SHPT treatment should be considered especially in patients with stage 3 to 5 CKD.

Lower Bone Turnover and Skeletal PTH Responsiveness in Japanese Compared to European Patients on Hemodialysis

CONTEXT

Parathyroid hormone (PTH) treatment targets for patients receiving hemodialysis (HD) are lower in Japan than in Europe. Whether this translates to lower bone turnover is unknown and could depend on skeletal PTH responsiveness.

OBJECTIVE

This study investigates whether skeletal PTH responsiveness is better preserved in Japanese vs European patients receiving HD.

METHODS

This is a post hoc analysis of data from 2 prospective cohort studies, using a case-control design. Patients receiving chronic intermittent HD therapy were eligible for inclusion. Participating Belgian and Japanese patients (n = 374) were matched 1:1 by age (59 ± 12 years), sex (66% male), diabetes (34%), and dialysis duration (39 months [22-63 months]). PTH, bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase isoform 5b (TRAP5b) were measured centrally in Liège, Belgium.

RESULTS

Japanese patients had lower levels of iPTH (207 vs 268 pg/mL; P < .001), BALP (15.3 vs 24.5 μg/L; P < .001), and TRAP5b (3.35 vs 5.79 U/L; P < .001). Linear regression analyses revealed lower levels of bone turnover markers for any given level of PTH in Japanese vs Belgian patients, indicating lower skeletal PTH responsiveness. Consistently, bone turnover markers were significantly lower in Japanese vs Belgian patients when stratifying or matching according to PTH levels. Male sex, obesity, and hyperphosphatemia were the main determinants of the bone turnover marker/PTH ratios.

CONCLUSION

Japanese patients receiving HD have lower bone turnover than their European counterparts, even at similar PTH levels. The rationale for the current regional differences in PTH treatment targets remains obscure and deserves further attention.

Relationship between sex and cardiovascular mortality in chronic kidney disease: A systematic review and meta-analysis

Chronic kidney disease (CKD) is a significant health challenge associated with high cardiovascular mortality risk. Historically, cardiovascular mortality risk has been found to higher in men than women in the general population. However, recent research has highlighted that this risk may be similar or even higher in women than men in the CKD population. To address the inconclusive and inconsistent evidence regarding this relationship between sex and cardiovascular mortality within CKD patients, a systematic review and meta-analysis of articles published between January 2004 and October 2020 using PubMed/Medline, EMBASE, Scopus and Cochrane databases was performed. Forty-eight studies were included that reported cardiovascular mortality among adult men relative to women with 95% confidence intervals (CI) or provided sufficient data to calculate risk estimates (RE). Random effects meta-analysis of reported and calculated estimates revealed that male sex was associated with elevated cardiovascular mortality in CKD patients (RE 1.13, CI 1.03-1.25). Subsequent subgroup analyses indicated higher risk in men in studies based in the USA and in men receiving haemodialysis or with non-dialysis-dependent CKD. Though men showed overall higher cardiovascular mortality risk than women, the increased risk was marginal, and appropriate risk awareness is necessary for both sexes with CKD. Further research is needed to understand the impact of treatment modality and geographical distribution on sex differences in cardiovascular mortality in CKD.

Differentiating the causes of adynamic bone in advanced chronic kidney disease informs osteoporosis treatment

Patients with chronic kidney disease (CKD) have an increased fracture risk because of impaired bone quality and quantity. Low bone mineral density predicts fracture risk in all CKD stages, including advanced CKD (CKD G4-5D). Pharmacological therapy improves bone mineral density and reduces fracture risk in moderate CKD. Its efficacy in advanced CKD remains to be determined, although pilot studies suggest a positive effect on bone mineral density. Currently, antiresorptive agents are the most commonly prescribed drugs for the prevention and therapy of osteoporosis. Their use in advanced CKD has been limited by the lack of large clinical trials and fear of causing kidney dysfunction and adynamic bone disease. In recent decades, adynamic bone disease has evolved as the most predominant form of renal osteodystrophy, commonly associated with poor outcomes, including premature mortality and progression of vascular calcification. Evolving evidence indicates that reduction of bone turnover by parathyroidectomy or pharmacological therapies, such as calcimimetics and antiresorptive agents, are not associated with premature mortality or accelerated vascular calcification in CKD. In contrast, chronic inflammation, oxidative stress, malnutrition, and diabetes can induce low bone turnover and associate with poor prognosis. Thus, the conditions causing suppression of bone turnover rather than the low bone turnover per se may account for the perceived association with outcomes. Anabolic treatment, in contrast, has been suggested to improve turnover and bone mass in patients with advanced CKD and low bone turnover; however, uncertainty about safety even exceeds that of antiresorptive agents. Here, we critically review the pathophysiological concept of adynamic bone disease and discuss the effect of low bone turnover on the safety and efficacy of anti-osteoporosis pharmacotherapy in advanced CKD.

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.

Cardiovascular risk assessment and coronary artery calcification burden in asymptomatic patients in the initial years of hemodialysis

The specific tool for cardiovascular risk assessment in hemodialysis population has not yet been proposed, despite high prevalence of cardiovascular morbidity, and mortality in clinically asymptomatic patients. Coronary artery calcium score (CACS), as a reliable predictor of future cardiovascular events, might be a valuable approach. We sought to evaluate coronary artery calcification burden and its association with clinical and laboratory parameters in asymptomatic patients who recently initiated hemodialysis. The cross-sectional study included 60 asymptomatic patients receiving chronic hemodialysis for no longer than 48 months. CACS was assessed by cardiac computed tomography. Intima-media thickness (IMT) of both common carotid and femoral arteries were measured using ultrasonography. The mean total CACS was 160.50 (443). Patients' age correlated significantly with CACS (σ = 0.367; P = 0.004), carotid (σ = 0.375; P = 0.004) and femoral IMT (σ = 0.323; P = 0.013). Patients with CACS = 0 were significantly younger than patients with CACS >400: 52.4 ± 7.91 vs. 63.88 ± 8.37 years old, respectively (P = 0.034). In patients receiving dialysis for longer than 24 months CACS, femoral and carotid IMT were higher than in those dialyzed for less than 24 months; however, none has reached significance. There was a significant positive correlation between CACS and right (σ = 0.312; P = 0.018) and left (σ = 0.521; P < 0.001) femoral IMT, while not with carotid. CACS showed significant negative correlation with the serum iron (σ = -0.351; P = 0.007). Calcification burden varies significantly in asymptomatic patients in early years of dialysis. It correlates with patients' age and tends to increase with dialysis vintage. Femoral IMT might be useful for cardiovascular risk stratification in asymptomatic patients who recently initiated hemodialysis.

The Association between Changes in Low Parathyroid Hormone Levels and Cardiac Function Decline in Maintenance Hemodialysis Patients: A Prospective Observational Study

OBJECTIVES

The aim of this study was to investigate a possible association between changes in low parathyroid hormone (PTH) levels and cardiac function decline in maintenance hemodialysis (MHD) patients.

METHODS

A total of 150 MHD patients were included and followed for 24 months. The enrolled patients were divided into 3 groups based on their PTH status at baseline and 24 months. Factors potentially involved in changes in the PTH level and cardiac function were compared using multivariate logistic regression analysis.

RESULTS

At 24 months, the presence of low PTH levels increased by 26.7%. The main independent factors for low PTH levels were a low BMI, hemoglobin, and serum albumin and high serum calcium (p < 0.05). A persistently low PTH level at 24 months was associated with a decrease in the left ventricular ejection fraction (LVEF) and increase in valvular calcification (p < 0.05). Additionally, a decrease in PTH levels from normal or high to low values was associated with a decrease in LVEF and cardiac output (CO) and an increase in valvular calcification (p < 0.05). Furthermore, compared with those of the persistently low PTH level group, LVEF values were lower at 24 months in the group with a decrease from high/normal to low PTH level (p < 0.05).

CONCLUSION

Persistently low PTH levels and changes in the PTH level from high/normal to low were associated with cardiac function decline in MHD patients. Moreover, a PTH level change from high/normal to low showed a stronger correlation with cardiac function decline.

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.

Changes in 3-month mineral and bone disorder patterns were associated with all-cause mortality in prevalent hemodialysis patients with secondary hyperparathyroidism

BACKGROUND

There is limited evidence on the association between short-term changes in mineral and bone disorder parameters and survival in maintenance hemodialysis patients.

METHODS

We investigated the association between changing patterns of phosphorus, calcium and intact parathyroid hormone levels and all-cause mortality in hemodialysis patients with secondary hyperparathyroidism. Each parameter was divided into three categories (low [L], middle [M] and high [H]), and the changing patterns between two consecutive visits at 3-month intervals were categorized into nine groups (e.g., L-L and M-H). The middle category was defined as 4.0-7.0 mg/dL for phosphorous, 8.5-9.5 mg/dL for calcium and 200-500 pg/mL for intact parathyroid hormone. Adjusted incidence rates and rate ratios were analyzed by weighted Poisson regression models accounting for time-dependent exposures.

RESULTS

For phosphorus, shifts from low/high to middle category (L-M/H-M) were associated with a lower mortality compared with the L-L and H-H groups, whereas shifts from middle to low/high category (M-L/M-H) were associated with a higher mortality compared with the M-M group. For calcium, shifts from low/middle to high category (L-H/M-H) were associated with a higher mortality compared with the L-L and M-M groups, whereas shifts from high to middle category (H-M) were associated with a lower mortality compared with the H-H group. For intact parathyroid hormone, shifts from low to middle category (L-M) were associated with a lower mortality compared with the L-L group.

CONCLUSIONS

Changes in the 3-month patterns of phosphorus and calcium toward the middle category were associated with lower mortality. Our study also suggests the importance of avoiding hypercalcemia.

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.

Effects of the dialysate calcium concentrations and mineral bone disease treatments on mortality in The French Renal Epidemiology and Information Network (REIN) registry

BACKGROUND

In patients on hemodialysis (HD), the various chemical elements in the dialysate may influence survival rates. In particular, calcium modifies mineral and bone metabolism and the vascular calcification rate. We studied the influence of the dialysate calcium concentration and the treatments prescribed for mineral bone disease (MBD) on survival.

METHODS

All patients in REIN having initiated HD from 2010 to 2013 were classified according to their exposure to the different dialysate calcium concentrations in their dialysis unit. Data on the individual patients' treatments for MBD were extracted from the French national health database. Cox proportional hazard models were used to estimate mortality hazard ratios (HR) associated with time-dependent exposure to dialysate calcium concentrations and MBD therapies, adjusted for comorbidities, laboratory and technical data.

RESULTS

Dialysate calcium concentration of 1.5 mmol/L was used by 81% of the dialysis centers in 2010 and in 83% in 2014. Most centers were using several formulas in up to 78% for 3 formulas in 2010 to 86% in 2014. In full adjusted Cox survival analyses, the percentage of calcium >1.5 mmol/L and <1.5 mmol/l by center and the number of formula used per center were not associated with survival. Depending on the daily dose used, the MBD therapies were associated with survival improvement for calcium, native vitamin D, active vitamin D, sevelamer, lanthanum and cinacalcet in the second and third tertiles of dose.

CONCLUSION

No influence of the dialysate calcium concentration was evidenced on survival whereas all MBD therapies were associated with a survival improvement depending on the daily dose used.

Effects of parathyroid hormone and vitamin D supplementation on stroke among patients receiving peritoneal dialysis

BACKGROUND

Continuous ambulatory peritoneal dialysis (CAPD) patients have a high incidence of stroke and commonly have increased parathyroid hormone levels and vitamin D insufficiency. We seek to investigate the incidence of stroke and the role of parathyroid hormone and vitamin D supplementation in stroke risk among CAPD patients.

METHODS

This study employed a retrospective design. We enrolled a Chinese cohort of 980 CAPD patients who were routinely followed in our department. The demographic and clinical data were recorded at the time of initial CAPD and during follow-up. The included patients were separated into non-stroke and stroke groups. The effects of parathyroid hormone and vitamin D supplementation on stroke in CAPD patients was evaluated. The primary endpoint is defined as the first occurrence of stroke, and composite endpoint events are defined as death or switch to hemodialysis during follow-up.

RESULTS

A total of 757 eligible CAPD patients with a mean follow-up time of 54.7 (standard deviation, 33) months were included in the study. The median incidence of stroke among our CAPD patients was 18.9 (interquartile range, 15.7-22.1) per 1000 person-years. A significant nonlinear correlation between baseline iPTH and hazard of stroke (p-value of linear association = 0.2 and nonlinear association = 0.002) was observed in our univariate Cox regression analysis, and low baseline iPTH levels (≤150 pg/ml) were associated with an increased cumulative hazard of stroke. Multivariate Cox regression analysis indicated a significant interaction effect between age and iPTH after adjusting for other confounders. Vitamin D supplementation during follow-up was a predictive factor for stroke in our cohort.

CONCLUSIONS

CAPD patients suffered a high risk of stroke, and lower iPTH levels were significantly correlated with an increased risk of stroke. Nevertheless, vitamin D supplementation may reduce the risk of stroke in these patients.

Relative prognostic impact of nutrition, anaemia, bone metabolism and cardiovascular comorbidities in elderly haemodialysis patients

BACKGROUND

The prognostic impact of nutrition and chronic kidney disease (CKD) complications has already been described in elderly haemodialysis patients but their relative weights on risk of death remain uncertain. Using structural equation models (SEMs), we aimed to model a single variable for nutrition, each CKD complication and cardiovascular comorbidities to compare their relative impact on elderly haemodialysis patients' survival.

METHODS

This prospective study recruited 3165 incident haemodialysis patients ≥75 years of age from 178 French dialysis units. Using SEMs, the following variables were computed: nutritional status, anaemia, mineral and bone disorder and cardiovascular comorbidities. Systolic blood pressure was also used in the analysis. Survival analyses used Poisson models.

RESULTS

The population average age was 81.9 years (median follow-up 1.51 years, 35.5% deaths). All variables were significantly associated with mortality by univariate analysis. Nutritional status was the variable most strongly associated with mortality in the multivariate analysis, with a negative prognostic impact of low nutritional markers {incidence rate ratio [IRR] 1.42 per 1 standard deviation [SD] decrement [95% confidence interval (CI) 1.32-1.53]}. The 'cardiovascular comorbidities' variable was the second variable associated with mortality [IRR 1.19 per 1 SD increment (95% CI 1.11-1.27)]. A trend towards low intact parathyroid hormone and high serum calcium and low values of systolic blood pressure were also associated with poor survival. The variable 'anaemia' was not associated with survival.

CONCLUSIONS

These findings should help physicians prioritize care in elderly haemodialysis patients with CKD complications, with special focus on nutritional status.

Detecting high-risk chronic kidney disease-mineral bone disorder phenotypes among patients on dialysis: a historical cohort study

BACKGROUND

The clinical management of chronic kidney disease-mineral bone disorder (CKD-MBD) remains extremely challenging, partially due to difficulties in defining high-risk phenotypes based on serum biomarkers. We evaluated the prevalence and outcomes of 27 mutually exclusive CKD-MBD phenotypes in a large, multi-national cohort of chronic dialysis patients over a 5-year follow-up study.

METHODS

In this historical cohort study, we enrolled all haemodialysis patients registered in EuCliD® on 1 July 2011 across 28 Europe, the Middle East and Africa (EMEA) and South American countries. We created 27 mutually exclusive phenotypes based on combinations of serum parathyroid hormone (PTH), phosphorus (P) and calcium (Ca) 6-month averages (L, low; T, target; H, high). We tested the association between CKD-MBD phenotypes and 5-year mortality and hospitalization risk by outcome risk score-adjusted proportional hazard regression.

RESULTS

We enrolled 35 721 eligible patients. Eastern European and South American countries generally achieved poorer CKD-MBD control when compared with Western European countries (prevalence ratio: 0.79; P < 0.001). There were 15 795 deaths [126.7 deaths/1000 person-years; 95% confidence interval (CI) 124.7-128.7]; 18 014 had at least one hospitalization (203.9 hospitalizations/1000 person-years; 95% CI 201.0-206.9); the incidence of the composite endpoint was 280.0 events/1000 person-years (95% CI 276.6-283.5). In the fully adjusted model, relative mortality risk ranged from hazard ratio (HR) = 1.07 (PTH/Ca/P: TLT) to HR = 1.59 (PTH/Ca/P: LTL), whereas the relative composite endpoint risk ranged from HR = 1.07 (PTH/Ca/P: TTH) to HR = 1.36 (PTH/Ca/P: LTL).

CONCLUSION

We identified several CKD-MBD phenotypes associated with reduced hospitalization-free survival and increased mortality. Ranking of relative risk estimates or excess events concurs in informing healthcare priority setting.

Higher Proportion of Non-1-84 PTH Fragments in Peritoneal Dialysis Patients Compared to Hemodialysis Patients Using Solutions Containing 1.75 mmol/l Calcium

Background: The prevalence of low- turnover bone disease (LTBD) in peritoneal dialysis (PD) patients is higher than in hemodialysis (HD) patients. LTBD patients may be at risk for vascular calcification, and cardiovascular disease. Current therapy for chronic kidney disease metabolic bone disorders (CKD-MBD) is guided by biochemical parameters, as bone biopsy is not used in routine clinical care. Methods: We assessed intact PTH (iPTH: 1-84PTH plus non-1-84PTH), 1-84PTH, and the 1-84PTH/non-1-84PTH ratio in 129 hemodialysis and 73 PD prevalent patients dialyzed with solutions containing 1.75 mmol/L calcium. Results: Hemodialysis and PD patients presented similar iPTH and tCa values and prevalence of putative LTBD as defined according to KDOQI iPTH cut-off levels or 1-84 PTH levels. However, iCa accounted for a higher percentage of tCa in PD (53%) than in hemodialysis (39%) p < 0.001, and the 1-84PTH/non-1-84PTH ratio was lower in PD than in hemodialysis patients (0.44 ± 0.12) vs. (0.60 ± 0.10), p < 0.001. The prevalence of putative LTBD when using the coexistence of 1-84PTH/non-1-84PTH ratio < 1.0 and iPTH < 420 pg/m, was higher in PD than in hemodialysis patients (73 vs. 16% respectively, p < 0.001). In a multivariate logistic regression analysis, dialysis modality was the main determinant of the 1-84PTH/non-1-84PTH ratio. Conclusion: Solutions containing 1.75 mmol/L calciums are associated to a higher proportion of non-1-84PTH fragments in PD than in HD patients. Different analytical criteria result in widely different estimates of LTBD prevalence, thus impairing the ability of clinicians to optimize therapy for CKD-MBD.

Conservative three-quarter versus subtotal seven-eighths parathyroidectomy in secondary hyperparathyroidism

OBJECTIVE

There is at present no consensus concerning surgical techniques for secondary hyperparathyroidism (SHPT) in end-stage renal disease (ESRD). Although both subtotal and total parathyroidectomy provide low rates of recurrence, they may induce hypoparathyroidism, damaging the bone and cardiovascular systems. The aim of our study was to compare 3/4 and 7/8 parathyroidectomy in this population and to discuss the potential benefit of more conservative treatment.

STUDY DESIGN

Prospective observational study in a university teaching hospital between 2010 and 2014.

METHODS

The study included 34 consecutive ESRD patients with SHPT: 19 underwent 3/4 parathyroidectomy (group A*3/4) and 15 underwent 7/8 parathyroidectomy (group B*7/8). Serum intact 1-84 PTH levels (before and 6 months after surgery) and hospital stay were compared between the two groups.

RESULTS

Before surgery, PTH levels were similar between the two groups. At month 6 following surgery, median PTH levels were significantly higher in group A*3/4 than in group B*7/8 (109 versus 24pg/mL, respectively; P<0.0006). Hospital stay was shorter in group A*3/4 (4.79 versus 6.80 days, respectively; P=0.008). Postoperative hypoparathyroidism requiring long-term calcium and 1alpha(OH) D3 treatment was reported in 5% of patients in group A*3/4 and 26% of patients in group B*7/8 (P=0.04).

CONCLUSIONS

In this preliminary study, 3/4 conservative parathyroidectomy seemed effective and safe, with less reported morbidity than 7/8 parathyroidectomy, as assessed by lower rates of irreversible hypoparathyroidism and shorter hospital stay.

LEVEL OF EVIDENCE

3b, individual case-control study.

Higher dialysate calcium concentration is associated with incident myocardial infarction among diabetic patients with low bone turnover: a longitudinal study

This is a longitudinal study on 53,560 hemodialysis patients from the Japan Renal Data Registry. Predictor was D[Ca] ≥3.0 vs 2.5 mEq/L. Outcomes were the first CV events during 1-year observation period. Association of D[Ca] with CV events and effect modifications were tested using multivariate logistic regression analyses. Diabetes mellitus (DM) was a significant effect modifier for association of higher D[Ca] and myocardial infarction (MI) (OR: 1.26 (1.03-1.55) among DM and 0.86 (0.72-1.03) among non-DM, p for interaction <0.01). The effect size was not affected by further adjustment for serum albumin-corrected Ca or intact parathyroid hormone (iPTH) levels, but was attenuated by adjustment for intradialytic change in serum Ca concentration (ΔCa) (1.16 [0.89-1.51]). Among DM, D[Ca] ≥3.0 mEq/L was significantly associated with MI in the first tertile of corrected Ca or iPTH ≤60 pg/ml (p for interaction 0.03 and 0.03, respectively). In conclusion, higher D[Ca] was associated with incident MI in DM, especially with low serum Ca or iPTH levels. Attenuation of the effect size by adjustment for ΔCa and stratified analyses suggest that larger Ca influx during dialysis with higher D[Ca] in patients suggestive of low bone turnover leads to vascular calcification and subsequent MI in DM.

Resurgence of parathyroidectomy: evidence and outcomes

PURPOSE OF REVIEW

Parathyroidectomy (PTx) is the definitive therapy for refractory secondary hyperparathyroidism (SHPT). The drastic effects of PTx on biochemical parameters of SHPT increases the possibility that this intervention will lead to a reduction in the adverse outcomes related to uncontrolled SHPT.

RECENT FINDINGS

The effect of PTx on mortality and cardiovascular outcomes among dialysis patients with severe SHPT have been evaluated in many observational studies from different regions of the world, including Asia, Europe, North America, and South America. In all but one small study, there was a significant association of PTx with lower all-cause mortality. In addition, in all studies, there was a trend in favor of PTx for cardiovascular morbidity and mortality. The effect of PTx on fractures has been evaluated in only one epidemiological study from the United States, which demonstrated a significant association of PTx and lower hip and combined fractures.

SUMMARY

Although randomized evidence is lacking, these highly consistent results may suggest a strong beneficial effect of PTx on long-term clinical outcomes and eliminate the potential concern of low parathyroid hormone after PTx.

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.

Hope for CKD-MBD Patients: New Diagnostic Approaches for Better Treatment of CKD-MBD

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) patients have a huge morbidity and mortality. Only relatively minor progress in therapeutic strategies has been made in the past decades. This is at least partially due to a lack of predictive diagnostic tools allowing personalized treatment of CKD-MBD patients.

SUMMARY

In this review we describe recent progress in the diagnosis of disturbances of calcium and phosphate metabolism in patients with CKD-MBD, measuring biological active nonoxidized parathyroid hormone as well as the overall likelihood of a patient to get calcified.

KEY MESSAGE

There is hope. The new tools have the potential of allowing personalized therapy for the treatment of CKD-MBD and hence improving outcome.

Osteoprotegerin Is the Strongest Predictor for Progression of Arterial Calcification in Peritoneal Dialysis Patients

BACKGROUND

Arterial calcification (AC) is frequent in patients with end stage renal disease and is also considered a risk factor for later morbidity and mortality. However, long-term factors associated with the process are not well known. We analyzed the trends over time of biomarkers related with development and progression of AC in incident patients on peritoneal dialysis (PD).

METHODS

We performed a prospective study with 186 patients on PD followed up for 1 year. We analyzed the progression of AC in the abdominal aorta and pelvic vessels by calcification score (CaSc), using16-cut computerized multidetector tomography at baseline and 1 year. Variables related with PD treatment, inflammation, and mineral metabolism were measured at baseline, 6, and 12 months of follow-up. Changes in biochemical variables were analyzed for their relationship with changes in AC.

RESULTS

Over 1 year, the number of patients with AC increased from 47 to 56%, and CaSc from 355 (interquartile range [IQR] 75-792) to 529 (IQR 185-1632). A total of 43.5% of patients remained free of calcification, 11.7% had new calcifications, and 44.8% had progression of calcification. Older age, diabetes, high systolic blood pressure, body mass index, cholesterol, and osteoprotegerin (OPG), as well as lower levels of albumin, serum creatinine, and osteocalcin, were associated with development of new, and rapid progression of, calcification. In multivariate logistic analysis, OPG remained the most significant (OR 1.27, 95% CI 1.11-1.47, p < 0.001).

CONCLUSION

OPG was the strongest risk factor associated with new development and rapid progression of AC in incident PD patients.

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.

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.