Renal allograft failure in a hyperparathyroid patient following initiation of a calcimimetic

Association Between Parathyroid Hormone-Related Peptide Levels and Mortality in Patients With Malignancy

OBJECTIVE

Hypercalcemia of malignancy is a risk factor for mortality in patients with malignancies. Although the parathyroid hormone-related protein (PTHrP) secreted by tumor cells induces hypercalcemia, the association between serum PTHrP levels and mortality remains unclear. This study aimed to investigate the association between serum PTHrP levels and mortality in patients with malignancies.

METHODS

We included patients with hypercalcemia (>10 mg/dL) and elevated PTHrP levels (>1.1 pmol/L) and analyzed mortality (overall survival after cancer diagnosis, PTHrP measurement, and 5-year survival rate). Moreover, using Cox proportional hazard model analysis, we investigated the impact of PTHrP levels on survival prognosis, assessing whether this effect varied depending on calcium concentration.

RESULTS

We analyzed the data of 183 patients. The median PTHrP level, corrected calcium level, and age were 5.5 (3.0-10.6) pmol/L, 12.5 (11.5-13.4) mg/dl, and 70 (61-76) years, respectively. PTHrP was significantly and linearly associated with serum calcium levels (correlation coefficient, 0.06; 95% CI: 0.039-0.081, t: 5.69; P < .001). The group with the highest PTHrP levels had significantly worse survival rates than the group with the lowest PTHrP levels (hazard ratio: 1.68, 95% CI 1.03-2.77, P = .038).

CONCLUSION

This study showed an association between PTHrP and mortality in patients with malignancy after adjusting for serum calcium levels.

Systematic Review of the Treatment of Persistent Hyperparathyroidism Following Kidney Transplantation

Chronic kidney disease-mineral and bone disorder is one of the complications associated with chronic kidney disease. About 10-50% of patients following kidney transplantation have persistent hyperparathyroidism. Hypercalcaemic hyperparathyroidism has a negative impact on the kidney transplant outcome; therefore, it requires treatment. The data regarding the treatment of persistent hyperparathyroidism provided in scientific publications are divergent and contradictory. Therefore, the aim of our systematic review was to evaluate the efficacy of persistent hyperparathyroidism treatment in patients following kidney transplantation. The Cochrane, PubMed, and Scopus databases were browsed independently by two authors. The search strategy included controlled vocabulary and keywords. The effectiveness of calcitriol, paricalcitol, cinacalcet, and parathyroidectomy was compared and analysed. The mean calcium and parathormone (PTH) concentrations per patient in the group of paricalcitol increased by 1.27% and decreased by 35.14% (n = 248); in the group of cinacalcet decreased by 12.09% and 32.16% (n = 368); and in the group of parathyroidectomy decreased by 19.06% and 86.49% (n = 15) at the end of the study compared to the baseline (n = 244, n = 342 and n = 15), respectively. Paricalcitol, cinacalcet, and parathyroidectomy decreased the intact PTH level. Cinacalcet and parathyroidectomy lowered calcium levels in renal transplant patients with hypercalcaemia. Conversely, paricalcitol increased the serum calcium concentration. Cinacalcet seems to be a good candidate in the treatment of post-transplant hyperparathyroidism.

Mineral and Bone Disorders After Kidney Transplantation

The risk of mineral and bone disorders among patients with chronic kidney disease is substantially elevated, owing largely to alterations in calcium, phosphorus, vitamin D, parathyroid hormone, and fibroblast growth factor 23. The interwoven relationship among these minerals and hormones results in maladaptive responses that are differentially affected by the process of kidney transplantation. Interpretation of conventional labs, imaging, and other fracture risk assessment tools are not standardized in the post-transplant setting. Post-transplant bone disease is not uniformly improved and considerable variation exists in monitoring and treatment practices. A spectrum of abnormalities such as hypophosphatemia, hypercalcemia, hyperparathyroidism, osteomalacia, osteopenia, and osteoporosis are commonly encountered in the post-transplant period. Thus, reducing fracture risk and other bone-related complications requires recognition of these abnormalities along with the risk incurred by concomitant immunosuppression use. As kidney transplant recipients continue to age, the drivers of bone disease vary throughout the post-transplant period among persistent hyperparathyroidism, de novo hyperparathyroidism, and osteoporosis. The use of anti-resorptive therapies require understanding of different options and the clinical scenarios that warrant their use. With limited studies underscoring clinical events such as fractures, expert understanding of MBD physiology, and surrogate marker interpretation is needed to determine ideal and individualized therapy.

Managing kidney transplant recipients in primary care

Patients who have undergone kidney transplant are at increased risk for heart disease, new-onset diabetes, metabolic syndrome, and certain malignancies, in addition to opportunistic infections associated with immunosuppression. This article describes guidelines for routine management of kidney transplant recipients in primary care, as well as how to recognize risk factors and complications.

Effect of cinacalcet cessation on hyperparathyroidism in kidney transcaplant patients after long-term dialysis therapy

BACKGROUND

Cinacalcet is a promising therapy widely used in dialysis patients with hyperparathyroidism resistant to conventional therapy. However, reports regarding the influence of cinacalcet cessation after long-term use on kidney transplantation patients are few.

METHODS

This retrospective observational study included 40 dialysis patients who underwent kidney transplantation. Creatinine, corrected calcium, phosphorus, alkaline phosphatase, and intact parathyroid hormone levels were assessed before and after kidney transplantation according to pretransplant treatment of chronic kidney disease-mineral and bone disorder.

RESULTS

Ultrasonography revealed enlargement of the parathyroid in all patients treated with cinacalcet. Although the data at the time of kidney transplantation were comparable, the serum levels of calcium, alkaline phosphatase, and intact parathyroid hormone after kidney transplantation were higher in patients treated with cinacalcet than in those treated without. However, serum phosphate levels in the cinacalcet group were slightly higher at the time of kidney transplantation and significantly lower 3 months later.

CONCLUSIONS

Mineral abnormalities persisted in kidney transplant patients with enlarged parathyroid glands after discontinuation of cinacalcet treatment. Parathyroidectomy should be considered in kidney transplant candidates with the risk of developing refractory hyperparathyroidism after transplantation.

Long-term clinical practice experience with cinacalcet for treatment of hypercalcemic hyperparathyroidism after kidney transplantation

Within this prospective, open-label, self-controlled study, we evaluated the long-term effects of the calcimimetic cinacalcet on calcium and phosphate homeostasis in 44 kidney transplant recipients (KTRs) with hypercalcemic hyperparathyroidism by comparing biochemical parameters of mineral metabolism between pre- and posttreatment periods. Results are described as mean differences (95% CIs) between pre- and posttreatment medians that summarize all repeated measurements of a parameter of interest between the date of initial hypercalcemia and cinacalcet initiation (median of 1.6 (IQR: 0.6-3.8) years) and up to four years after treatment start, respectively. Cinacalcet was initiated after 1.8 (0.8-4.7) years posttransplant and maintained for 6.2 (3.9-7.6) years. It significantly decreased total serum calcium (-0.30 (-0.34 to -0.26) mmol/L, P < 0.001) and parathyroid hormone levels (-79 (-103 to -55) pg/mL, P < 0.001). Serum levels of inorganic phosphate (Pi) and renal tubular reabsorption of phosphate to glomerular filtration rate (TmP/GFR) increased simultaneously (Pi: 0.19 (0.15-0.23) mmol/L, P < 0.001, TmP/GFR: 0.20 (0.16-0.23) mmol/L, P < 0.001). In summary, cinacalcet effectively controlled hypercalcemic hyperparathyroidism in KTRs in the long-term and increased low Pi levels without causing hyperphosphatemia, pointing towards a novel indication for the use of cinacalcet in KTRs.

Vitamin D and cinacalcet administration pre-transplantation predict hypercalcaemic hyperparathyroidism post-transplantation: a case-control study of 355 deceased-donor renal transplant recipients over 3 years

BACKGROUND

The effects of pre-transplantation medication for secondary hyperparathyroidism on post-transplantation parathyroid hormone (PTH) and calcium levels have not yet been conclusively determined. Therefore, this study sought to determine the level of off-label use of cinacalcet and to determine predictors of its administration during the long-term follow-up of a cohort of individuals who received deceased-donor renal transplants. Furthermore, safety considerations concerning the off-label use of cinacalcet are addressed.

METHODS

This was a case-control study of 355 stable renal transplant recipients. The patient cohort was divided into two groups. Transplant group A comprised patients who did not receive cinacalcet treatment, and transplant group B comprised patients who received cinacalcet treatment during follow-up after renal transplantation. The characteristics of the patients were evaluated to determine predictors of cinacalcet use after successful renal transplantation.

RESULTS

Compared with the control individuals (n = 300), the cinacalcet-treated individuals (n = 55) had significantly higher PTH levels at 4 weeks post-transplantation (20.3 ± 1.6 versus 40.7 ± 4.0 pmol/L, p = 0.0000) when they were drug naive. At 3.2 years post-transplantation, cinacalcet-treated patients showed higher PTH (26.2 ± 2.3 versus 18.4 ± 2.3 pmol/L, p = 0.0000), higher calcium (2.42 ± 0.03 versus 2.33 ± 0.01 mmol/L, p = 0.0045) and lower phosphate (0.95 ± 0.04 versus 1.06 ± 0.17 mmol/L, p = 0.0021) levels. Individuals in the verum group were more likely to receive cinacalcet therapy (45.5% versus 14.3%, p = 0.0000), and they had higher pill burdens for the treatment of hyperparathyroidism (1.40 ± 0.08 versus 0.72 ± 0.03 pills per patient, p = 0.0000) whilst they were on the waiting list for transplantation. Regression analysis confirmed the associations between hypercalcaemic hyperparathyroidism and PTH levels at 4 weeks post-transplantation (p = 0.0001), cinacalcet use (p = 0.0000) and the preoperative total pill burden (p = 0.0000). Renal function was the same in both groups.

CONCLUSIONS

Parathyroid gland dysfunction pre-transplantation translates into clinically relevant hyperparathyroidism post-transplantation, despite patients being administered more intensive treatment whilst on dialysis. PTH levels at 4 weeks post-transplantation might serve as a marker for the occurrence of hypercalcaemic hyperparathyroidism during follow-up.

Cinacalcet for the treatment of hyperparathyroidism in kidney transplant recipients: a systematic review and meta-analysis

BACKGROUND

Hyperparathyroidism is present in up to 50% of transplant recipients 1 year after transplant, often despite good graft function. Posttransplant patients frequently have hypercalcemia-associated hyperparathyroidism, limiting the role of vitamin D analogues and sometimes requiring parathyroidectomy. Multiple observational studies have investigated treatment of posttransplant hyperparathyroidism with the calcimimetic agent cinacalcet.

METHODS

We performed a systematic review and meta-analysis of prospective and retrospective studies from 2004 through January 26, 2012, using MEDLINE. We identified studies evaluating treatment with cinacalcet in renal transplant recipients with hyperparathyroidism. We performed random effects meta-analysis to determine changes in calcium, phosphorus, parathyroid hormone, and serum creatinine.

RESULTS

Twenty-one studies with 411 kidney transplant recipients treated with cinacalcet for hyperparathyroidism met inclusion criteria. Patients were treated for 3 to 24 months. By meta-analysis, calcium decreased by 1.14 mg/dL (95% confidence interval, -1.00 to -1.28), phosphorus increased by 0.46 mg/dL (95% confidence interval, 0.28-0.64), parathyroid hormone decreased by 102 pg/mL (95% confidence interval, -69 to -134), and there was no significant change in creatinine (0.02 mg/dL decrease; 95% confidence interval, -0.09 to 0.06). Cinacalcet resulted in hypocalcemia in seven patients. The most common side effect was gastrointestinal intolerance.

CONCLUSIONS

From nonrandomized studies, cinacalcet appears to be safe and effective for the treatment of posttransplant hyperparathyroidism. Larger observational studies and randomized controlled trials, performed over longer follow-up times and looking at clinical outcomes, are needed to corroborate these findings.

CKD-mineral and bone disorder management in kidney transplant recipients

Kidney transplantation, the most effective treatment for the metabolic abnormalities of chronic kidney disease (CKD), only partially corrects CKD-mineral and bone disorders. Posttransplantation bone disease, one of the major complications of kidney transplantation, is characterized by accelerated loss of bone mineral density and increased risk of fractures and osteonecrosis. The pathogenesis of posttransplantation bone disease is multifactorial and includes the persistent manifestations of pretransplantation CKD-mineral and bone disorder, peritransplantation changes in the fibroblast growth factor 23-parathyroid hormone-vitamin D axis, metabolic perturbations such as persistent hypophosphatemia and hypercalcemia, and the effects of immunosuppressive therapies. Posttransplantation fractures occur more commonly at peripheral than central sites. Although there is significant loss of bone density after transplantation, the evidence linking posttransplantation bone loss and subsequent fracture risk is circumstantial. Presently, there are no prospective clinical trials that define the optimal therapy for posttransplantation bone disease. Combined pharmacologic therapy that targets multiple components of the disordered pathways has been used. Although bisphosphonate or calcitriol therapy can preserve bone mineral density after transplantation, there is no evidence that these agents decrease fracture risk. Moreover, bisphosphonates pose potential risks for adynamic bone disease.

Hyperparathyroidism in chronic kidney disease: complexities within the commonplace

Secondary hyperparathyroidism in patients with chronic kidney disease (CKD) is common and usually caused by associated metabolic abnormalities, in particular, hypocalcaemia and hyperphosphataemia. Nevertheless, other causes of hyperparathyroidism can exist concurrently with CKD, challenging diagnostic interpretation and therapeutic intervention. We present four cases of hyperparathyroidism in patients with CKD that highlight some of these dilemmas.