Achievement of NKF/K-DOQI recommended target values for bone and mineral metabolism in incident hemodialysis patients: results of the FARO-2 cohort

Parathyroidectomy and survival in a cohort of Italian dialysis patients: results of a multicenter, observational, prospective study

BACKGROUND

Severe secondary hyperparathyroidism (SHPT) is associated with mortality in end stage kidney disease (ESKD). Parathyroidectomy (PTX) becomes necessary when medical therapy fails, thus highlighting the interest to compare biochemical and clinical outcomes of patients receiving either medical treatment or surgery.

METHODS

We aimed to compare overall survival and biochemical control of hemodialysis patients with severe hyperparathyroidism, treated by surgery or medical therapy followed-up for 36 months. Inclusion criteria were age older than 18 years, renal failure requiring dialysis treatment (hemodialysis or peritoneal dialysis) and ability to sign the consent form. A control group of 418 patients treated in the same centers, who did not undergo parathyroidectomy was selected after matching for age, sex, and dialysis vintage.

RESULTS

From 82 Dialysis units in Italy, we prospectively collected data of 257 prevalent patients who underwent parathyroidectomy (age 58.2 ± 12.8 years; M/F: 44%/56%, dialysis vintage: 15.5 ± 8.4 years) and of 418 control patients who did not undergo parathyroidectomy (age 60.3 ± 14.4 years; M/F 44%/56%; dialysis vintage 11.2 ± 7.6 y). The survival rate was higher in the group that underwent parathyroidectomy (Kaplan-Meier log rank test = 0.002). Univariable analysis (HR 0.556, CI: 0.387-0.800, p = 0.002) and multivariable analysis (HR 0.671, CI:0.465-0.970, p = 0.034), identified parathyroidectomy as a protective factor of overall survival. The prevalence of patients at KDOQI targets for PTH was lower in patients who underwent parathyroidectomy compared to controls (PTX vs non-PTX: PTH < 150 pg/ml: 59% vs 21%, p = 0.001; PTH at target: 18% vs 37% p = 0.001; PTH > 300 pg/ml 23% vs 42% p = 0.001). The control group received more intensive medical treatment with higher prevalence of vitamin D (65% vs 41%, p = 0.0001), calcimimetics (34% vs 14%, p = 0.0001) and phosphate binders (77% vs 66%, p = 0.002).

CONCLUSIONS

Our data suggest that parathyroidectomy is associated with survival rate at 36 months, independently of biochemical control. Lower exposure to high PTH levels could represent an advantage in the long term.

The current status of chronic kidney disease-mineral and bone disorder management in China

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is one of the most common complications of patients with chronic kidney disease (CKD). After considering updated international and domestic CKD-MBD management guidelines, the current management status of CKD-MBD in China remains unclear. We aimed to investigate the management status of CKD-MBD in China. A nationwide survey was combined with a real-world study from Sichuan. Targets recommended in KDIGO 2017 and Chinese 2019 guidelines were used as targets. We compared the data between Sichuan from western China and the eastern developed areas of China, and also compared the results of the real-world data from Sichuan with those of DOPPS5. In the questionnaire, a total of 51,039 maintenance hemodialysis (MHD) patients from 272 centers were involved. Estimated achievement rates for Ca (2.1–2.5 mmol/L), P (1.13–1.78 mmol/L), and iPTH (150–600 pg/mL) levels were 57.1%, 41.1% and 52.0%, respectively. Differences in MBD management between Sichuan from questionnaire and central region. In the real-world survey, a total of 7,053 patients were enrolled. Among them, 57.6%, 24.3%, and 55.0% of patients met corrected Ca, serum P, and iPTH targets specified in Chinese 2019 guidelines, respectively. The comprehensive achievement rate was 7.5%. There are differences in MBD management between Sichuan and DOPPS5 regions, with Sichuan being relatively poorer. The level of the above parameters varies among different genders, age groups, and hospital grades. The achievement rate of serum P was higher in tertiary hospitals and elderly patients (P < 0.05). Current MBD management is poor. Phosphate levels in patients treated in secondary and lower hospitals and young dialysis patients should be strengthened.

Improvements in six aspects of quality of care of incident hemodialysis patients - a real-world experience

Background

The transition from chronic kidney disease stage 5 to initiation of hemodialysis has gained increased attention in recent years as this period is one of high risk for patients with an annual mortality rate exceeding 20%. Morbidity and mortality in incident hemodialysis patients are partially attributed to failure to attain guideline-based targets. This study focuses on improvements in six aspects of quality of dialysis care (adequacy, anemia, nutrition, chronic kidney disease-mineral bone disorder (CKD-MBD), blood pressure and vascular access) aligning with KDIGO guidelines, during the first 6 months of hemodialysis.

Methods

We analyzed patient demographics, practice patterns and laboratory data in all 3 462 patients (mean age 65.9 years, 41% females) on hemodialysis (incident <90 days on hemodialysis, n=603, prevalent ≥90 days on hemodialysis, mean 55 months, n=2 859) from all 56 DaVita centers in Poland (51 centers) and Portugal (5 centers). 80% of patients had hemodialysis and 20% hemodiafiltration. Statistical analyses included unpaired and paired Students t-test, Chi-2 analyses, McNemar test and logistic regression analysis.

Results

Incident patients had lower Kt/V (1.4 vs 1.7, p<0.001), lower serum albumin (37 vs 40 g/l, p=0.001), lower Hb (9.9 vs 11.0 g/dl, p<0.001), lower TSAT (26 vs 31%, p<0.001), lower iPTH (372 vs 496 pg/ml, p<0.001), more often a central venous catheter (68 vs 26%, p<0.001), less often an AV fistula (34 vs 70 %, p<0.001) compared with all prevalent patients. Significantly more prevalent patients achieved international treatment targets.

Improvements in quality of care was also analyzed in a subgroup of 258 incident patients who were followed prospectively for 6 months. We observed significant improvements in Kt/V (p<0.001), albumin (p<0.001), Hb (p<0.001) transferrin saturation (TSAT, p<0.001), iPTH (p=0.005) and an increased use of AV fistula (p<0.001). Furthermore, logistic regression analyses identified treatment time and TSAT as major factors influencing the attainment of adequacy and anemia treatment targets.

Conclusion

This large real-world European multicenter analysis of representative incident hemodialysis patients indicates that the use of medical protocols and medical targets assures significant improvements in quality of care, which may correspond to better outcomes. A selection bias of survivors with less comorbidities in prevalent patients may have influenced the results.

A review and perspective on the assessment, management and prevention of fragility fractures in patients with osteoporosis and chronic kidney disease

This article aims to review the methods used for the assessment of fracture risk and the use of osteoporosis medications for fracture prevention in the population with CKD, and highlights the difficulties faced by clinicians in the management of these patients and the latest recommendations and guidelines. Chronic kidney disease (CKD) and osteoporosis often co-exist in older adults, and they present a major healthcare challenge. CKD mineral and bone disorder (CKD-MBD) occurs as renal function declines and this syndrome affects most patients in CKD stages 4 and 5. The biochemical abnormalities of CKD-MBD, renal bone disease and risk factors associated with age-related bone loss and osteoporosis lead to a cumulative effect on fracture risk and mortality. There is a need for routine evaluation of fracture risk and fracture prevention in this population. Measurement of bone mineral density (BMD) and the use of the FRAX tool have predictive value for incident fractures in the general population and in CKD. This enables physicians to identify CKD patients most at risk of sustaining a fragility fracture and allows a more targeted approach to fracture prevention. Data analysis from the pivotal trials of therapeutic agents used in osteoporosis show that these drugs can be considered in mild and moderate CKD (stages 1-3 CKD). Off-label drug use in patients with CKD-MBD and more severe renal impairment (CKD stages 4 and 5) could offer significant benefits to sub-groups of patients when carefully tailored to each individual's bone turnover and calcium and phosphate balance. However, this requires a selective approach and treatment decisions based on inference from pathophysiology while we await further trials. Guidelines advocate the correction and/or reduction of the biochemical abnormalities of CKD-MBD before initiation of treatment with osteoporosis drugs and close monitoring during treatment.

Association between the risk of death and serum calcium, phosphate, and intact parathyroid hormone levels in older patients undergoing maintenance hemodialysis: a cohort study in Beijing

BACKGROUND

The number of patients ⩾65 years who require maintenance hemodialysis (MHD) is increasing. Although reduced bone turnover in older patients receiving hemodialysis, as reflected by lower serum intact parathyroid hormone (iPTH) and phosphate (P) levels, has been reported, focus on the association between abnormal bone metabolism and the risk of death in older patients receiving MHD has been limited.

METHODS

We retrospectively examined data from the Beijing Hemodialysis Quality Control and Improvement Center for 1410 older patients who underwent hemodialysis from 1 January 2012 to 31 December 2016. Baseline, time-dependent (TD) Cox proportional hazards models and Kaplan-Meier analyses were used to evaluate the association between the markers of mineral and bone disorder (MBD) [calcium (Ca), P, and iPTH] and survival. The Kidney Disease: Improving Global Outcomes (KDIGO) target ranges were included as reference values.

RESULTS

Serum P levels >2.49 mmol/l increased the risk of all-cause death [hazard ratio (HR): 1.46; 95% confidence interval (CI): 1.04-2.07; p = 0.030] and cardiovascular death (HR: 2.01; 95%CI: 1.21-3.34; p = 0.007); iPTH levels >600 pg/ml increased the risk of cardiovascular death (HR: 1.95; 95%CI: 1.20-3.15; p = 0.007). Baseline results and TD Cox analyses were similar. All three MBD parameters were within the respective target ranges at least once during the follow-up period in 399 (28.3%) patients, and these patients had better survival rates than those who achieved two of the three target ranges (715/1410 patients; 50.7%); those who achieved one or no target range (296/1410; 21.0%) had the lowest survival rate (all-cause death: log-rank chi square = 83.96, p < 0.001; cardiovascular death: log-rank chi square = 47.06, p < 0.001).

CONCLUSION

Older patients undergoing MHD who achieved the KDIGO target levels for any two or three MBD parameters had lower risks of all-cause and cardiovascular death.

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.

Development of a quantitative systems pharmacology model of chronic kidney disease: metabolic bone disorder

Chronic kidney disease mineral bone disorder (CKD-MBD) is a virtually universal complication of kidney diseases, starting early in the course of disease and resulting in devastating clinical consequences ranging from bone fragility to accelerated atherosclerosis and early cardiovascular death. Guidelines for therapeutic goals for CKD-MBD have been published, and achievement of these guidelines is associated with improved survival. However, the incomplete understanding of CKD-MBD and the individual variability in the manifestations of CKD-MBD have made it difficult to achieve these guidelines. We hypothesized that the progression of MBD through all stages of CKD, including end-stage kidney disease, could be represented by a quantitative systems pharmacology/systems biology (QSP) model. To address this hypothesis, we constructed a QSP model of CKD-MBD, building on an open-source model of calcium and phosphorus metabolism. Specifically, we estimated and validated the model using data from 5,496 patients with CKD enrolled in the Chronic Renal Insufficiency Cohort study. Our model accurately predicted changes in markers of mineral metabolism related to progressing CKD. We demonstrated that the incorporation of fibroblast growth factor 23 and the soft tissue compartment is essential for accurate modeling of the changes in calcium, phosphorus, intact parathyroid hormone, and calcitriol in CKD-MBD. We conclude that our systems biology model accurately represents CKD-MBD disease progression and can be used as a test bench for improving therapeutic interventions.

Association of changes in bone mineral parameters with mortality in haemodialysis patients: insights from the ARO cohort

BACKGROUND

There is little information in haemodialysis (HD) patients on whether temporal changes in serum calcium, phosphate or intact parathyroid hormone (iPTH) are associated with mortality.

METHODS

We analysed associations of phosphate, total calcium and iPTH with all-cause and cardiovascular mortality in 8817 incident HD patients from the European second Analyzing Data, Recognizing Excellence and Optimizing Outcomes (AROii) cohort enrolled in 2007-09, which were prospectively followed for a median of 3 years, using time-dependent Cox proportional hazards models. We evaluated changes in risk over time depending on changes in phosphate, calcium or iPTH.

RESULTS

The association of phosphate and iPTH with all-cause mortality was U-shaped, with the lowest risk ranges between 1.20 and 1.89 mmol/L for phosphate and between 239 and 710 ng/L for iPTH. For total calcium, the associations were J-shaped, with an increased risk for all-cause mortality at levels >2.36 mmol/L. Lowest risk ranges for cardiovascular mortality did not change markedly for all three parameters. If iPTH was below the lowest risk range at baseline (iPTH <239 ng/L), a subsequent increase in levels was associated with improved survival. For phosphate, an increase or decrease out of the lowest risk range was associated with increased mortality risk. For calcium, this was only the case when the values increased above the lowest risk range.

CONCLUSION

In the AROii cohort, the ranges of bone mineral biomarkers associated with the lowest mortality ranges were largely consistent with the current Kidney Disease: Improving Global Outcomes chronic kidney disease-mineral and bone disorder guideline recommendations. Allowing a suppressed iPTH to increase was associated with a lower mortality, whereas shifts of phosphate or calcium outside the lowest risk range increased mortality.

Consensus statement from 2nd International Conference on Controversies in Vitamin D

The 2nd International Conference on Controversies in Vitamin D was held in Monteriggioni (Siena), Italy, September 11-14, 2018. The aim of this meeting was to address ongoing controversies and timely topics in vitamin D research, to review available data related to these topics and controversies, to promote discussion to help resolve lingering issues and ultimately to suggest a research agenda to clarify areas of uncertainty. Several issues from the first conference, held in 2017, were revisited, such as assays used to determine serum 25-hydroxyvitamin D [25(OH)D] concentration, which remains a critical and controversial issue for defining vitamin D status. Definitions of vitamin D nutritional status (i.e. sufficiency, insufficiency and deficiency) were also revisited. New areas were reviewed, including vitamin D threshold values and how they should be defined in the context of specific diseases, sources of vitamin D and risk factors associated with vitamin D deficiency. Non-skeletal aspects related to vitamin D were also discussed, including the reproductive system, neurology, chronic kidney disease and falls. The therapeutic role of vitamin D and findings from recent clinical trials were also addressed. The topics were considered by 3 focus groups and divided into three main areas: 1) "Laboratory": assays and threshold values to define vitamin D status; 2) "Clinical": sources of vitamin D and risk factors and role of vitamin D in non-skeletal disease and 3) "Therapeutics": controversial issues on observational studies and recent randomized controlled trials. In this report, we present a summary of our findings.

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

RATIONALE & OBJECTIVE

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

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

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

PREDICTOR

Time since HD initiation.

OUTCOMES

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Association of Dose and Frequency on the Survival of Patients on Maintenance of Hemodialysis in China: A Kaplan-Meier and Cox-Proportional Hazard Model Analysis

Background

Dialysis frequency and dose are controversial prognostic factors of hemodialysis morbidity and mortality. The aim of this study was to find out the effect of frequency and dosage of dialysis on mortality and survival in a group of Chinese hemodialysis patients.

Material/Methods

In total, 183 patients seen from February 2008 to January 2018, who were on maintenance hemodialysis for at least 3 months, were included in the study cohort. An anonymized database of age, gender, diabetic status, comorbidities, date of initiation of dialysis, hematological characters, biochemical variables, and status of survived or died was established from DICOM (Digital Imaging and Communications in Medicine) files of patients. Kaplan-Meier and Cox-proportional hazard model was used for calculation of survival over time at 95% confidence level.

Results

Overall, the 10-year survival rate was 27%. Kaplan-Meier analysis showed patient survival as 94% at one-year, 59% at 5-years, and 27% at 10-years. Hemoglobin, serum albumin, calcium, potassium, phosphorous, calcium-phosphorous-products, and hemodialysis frequency and the dose had a significant effect on survival. Cox regression proportional hazard model showed that patients with serum albumin level of >4 g/dL were better associated with survival. Patients who underwent twice-weekly hemodialysis had 4.26 times less chance of survival as compared to patients with thrice-weekly hemodialysis. A higher dialysis dose of >1.2 spKt/V offered better survival as compared to a lower dose of <1.2 spKt/V.

Conclusions

Hypoalbuminemia, hemodialysis time, and hemodialysis frequency were significantly associated with mortality.

CKD-MBD KDIGO guidelines: how difficult is reaching the 'target'?

Patients with chronic kidney disease (CKD) are affected by mineral and bone disorder (MBD), resulting in abnormalities in serum calcium (Ca), phosphorous (P) and parathyroid hormone (PTH). Changes in mineral metabolism have also been associated with higher rates of both all-cause and cardiovascular-related mortality. The majority of haemodialysis patients are also deficient in the endogenous hormone 1,25-dihydroxyvitamin D (calcitriol), often contributing to increased secondary hyperparathyroidism (SHPT) and consequently to abnormal levels of Ca, P and PTH. Thus P overload and SHPT are well-known targets of medical treatments, such as P binders, vitamin D and calcimimetics, although with still limited evidence-based advantages in terms of survival. The tough hedge that is still keeping nephrologists far from a conclusive and winning approach against CKD-MBD is reasonably related to the still partial comprehension of the molecular pathways involved in a complex, multifactorial and extreme process.

Association between Extreme Values of Markers of Chronic Kidney Disease: Mineral and Bone Disorder and 5-Year Mortality among Prevalent Hemodialysis Patients

BACKGROUND/AIMS

We examined the association between markers of chronic kidney disease - mineral and bone disorder (CKD-MBD) and mortality in hemodialysis (HD) patients.

METHODS

We retrospectively reviewed the association between markers of CKD-MBD and mortality in 1,126 HD patients from 2009 to 2013 with baseline (B), time-average (TA), and time-dependent (TD) Cox regression models.

RESULTS

Hypercalcemia (10.9-11.9 mg/dL) indicated an increased risk of all-cause mortality (TA: hazard ratio [HR] 3.49; p = 0.01). Hypophosphatemia (2.0-2.5 mg/dL) was significantly associated with an increased risk of all-cause mortality (TA: HR 5.18; p = 0.01). Hypophosphatemia (<2.0 mg/dL) was significantly associated with an increased risk of cardiovascular mortality in all models. Intact parathyroid hormone levels <60 and >1,500 pg/mL indicated an increased risk of all-cause mortality (TA: HR 1.64; p = 0.02; TD: HR 2.26; p = 0.02).

CONCLUSION

Extreme values of CKD-MBD markers are associated with mortality risk in HD patients. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=478972.

Association between the Achievement of Target Range CKD-MBD Markers and Mortality in Prevalent Hemodialysis Patients in Taiwan by Using the Kidney Disease: Improving Global Outcomes Clinical Guidelines

Background. This study evaluated the association between achieving target chronic kidney disease-mineral and bone disorder (CKD-MBD) marker levels and mortality in Taiwanese hemodialysis (HD) patients. Target levels were based on the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Methods. We performed a retrospective medical record review of 1126 HD patients between 2009 and 2013. A logistic regression model was used to evaluate the relationship between achieving target marker levels and the risk for all-cause and cardiovascular (CV) mortality. Reference target ranges were 7.9 ≤ calcium (Ca) ≤ 9.9 mg/dL, 2.4 ≤ phosphate (P) ≤ 4.7 mg/dL, and 144 ≤ intact parathyroid hormone (iPTH) ≤ 648 pg/mL. Results. Achievement of target P levels was associated with a lower risk for all-cause mortality compared to achievement of either target Ca or iPTH levels. Achieving target P + iPTH levels (OR 1.32) was associated with a lower odds ratio for all-cause mortality compared to achieving target Ca + P (OR 1.66) and Ca + iPTH (OR 1.43) levels. Similar trends were observed for CV mortality risk. Conclusions. The present study demonstrated that achieving serum P levels within the KDIGO target range is the most important factor for lowering mortality in HD patients.

Changes in Markers of Mineral and Bone Disorders and Mortality in Incident Hemodialysis Patients

BACKGROUND

Abnormalities in mineral and bone disorder (MBD) markers are common in patients with chronic kidney disease. However, previous studies have not accounted for their changes over time, and it is unclear whether these changes are associated with survival.

METHODS

We examined the association of change in MBD markers (serum phosphorus (Phos), albumin-corrected calcium (Ca(Alb)), intact parathyroid hormone (iPTH) and alkaline phosphatase (ALP)) during the first 6 months of hemodialysis (HD) with all-cause mortality across baseline MBD strata using survival models adjusted for clinical characteristics and laboratory measurements in 102,754 incident HD patients treated in a large dialysis organization between 2007 and 2011.

RESULTS

Across all MBD markers (Phos, Ca(Alb), iPTH and ALP), among patients whose baseline MBD levels were higher than the reference range, increase in MBD levels was associated with higher mortality (reference group: MBD level within reference range at baseline and no change at 6 months follow-up). Conversely, decrease in Phos and iPTH, among baseline Phos and iPTH levels lower than the reference range, respectively, were associated with higher mortality. An increase in ALP was associated with higher mortality across baseline strata of ALP ≥80 U/l. However, patients with baseline ALP <80 U/l trended towards a lower risk of mortality irrespective of the direction of change at 6 months follow-up.

CONCLUSIONS

There is a differential association between changes in MBD markers with mortality across varying baseline levels in HD patients. Further study is needed to determine if consideration of both baseline and longitudinal changes in the management of MBD derangements improves outcomes in this population.