Hyperparathyroïdie secondaire et anémie. Effets d’un calcimimétique sur le contrôle de l’anémie des hémodialysés chroniques. Étude pilote

“Ideal” parathyroid hormone in erythropoietin‐stimulating agents‐resistant anemia

Erythropoietin‐stimulating agents (ESAs) have revolutionized anemia treatment in end‐stage renal disease (ESRD), but ESA resistance is increasingly identified. Secondary hyperparathyroidism (SHP) is one cause of ESA resistance. We describe a patient with ESA‐resistant, transfusion‐dependent anemia and mild SHP with remodeling and reticulin fibrosis on bone marrow biopsy, all of which resolved with stricter SHP management. We identified 64 patients with anemia, ESRD, and bone marrow biopsy. The parathyroid hormone (PTH) range for bony remodeling was 183–16,161.9 pg/ml versus 90.8–3283 pg/ml. The PTH range for fibrotic changes was 183–2487 pg/ml versus 90.8–16,161.9 pg/ml. We found no clear PTH range predictive for bone marrow changes.

Treatment with Cinacalcet in Hemodialysis Patients with Severe Secondary Hyperparathyroidism, Influences Bone Mineral Metabolism and Anemia Parameters

Background:

Due to the premium rate of Chronic Kidney Disease, we have increased our knowledge with respect to diagnosis and treatment of Bone Mineral Disease (BMD) in End- Stage Renal Disease (ESRD). Currently, various treatment options are available. The medication used for Secondary Hyper-Parathyroidism gives promising results in the regulation of Ca, P and Parathormone levels, improving the quality of life. The aim of the present study was to investigate the relation of cinacalcet administration to not only parathormone, Ca and P but also to anemia parameters such as hematocrit and hemoglobin.

Materials and Methods:

retrospective observational study was conducted in a Chronic Hemodialysis Unit. One-hundred ESRD patients were recruited for twenty-four months and were evaluated on a monthly rate. Biochemical parameters were related to medication prescribed and the prognostic value was estimated. Cinacalcet was administered to 43 out of 100 patients in a dose of 30-120 mg.

Results:

Significant differences were observed in PTH, Ca and P levels with respect to Cinacalcet administration. Ca levels appeared to be higher at 30mg as compared to 60mg cinacalcet. Furthermore, a decreasing age-dependent pattern was observed with respect to cinacalcet dosage. A positive correlation was observed between Dry Weight (DW) and cinacalcet dose. Finally, a positive correlation between Hematocrit and Hemoglobin and cinacalcet was manifested.

Conclusions:

Cinacalcet, is a potential cardiovascular and bone protective agent, which is approved for use in ESRD patients to assist SHPT. A novel information was obtained from this study, regarding the improvement of the control of anemia.

Factors associated with erythropoiesis-stimulating agent hyporesponsiveness anemia in chronic kidney disease patients

Anemia is one of the most common problems in chronic kidney disease (CKD). Despite comprehensive investigations in several cases, definite causes of anemia frequently remain unknown. Our study aimed to analyze the factors that possibly affect anemia in CKD patients who were referred for hematology consultation. A total of 87 patients were retrospectively included in the cohort. Forty-four cases were excluded, including 30 cases with unavailable intact parathyroid hormone (iPTH) data, 11 cases with bone marrow diseases (8 Pure red cell aplasia, 3 Myelodysplastic syndrome) and 3 cases with thalassemia. In total, 43 patients were analyzed. Patients with high iPTH had a significantly lower Hemoglobin (Hb) level and required a higher dose of erythropoiesis stimulating agents (ESAs) compared with the normal iPTH group (Hb 8.29 vs 9.24 mg/dL, P=0.032 and ESAs dose of 16,352.94 vs. 12,444.44 U/week, P=0.024). Univariate, followed by stepwise multivariate analysis was performed and determined that serum phosphate (PO4) was significantly associated with lower Hb level (P=0.01 and P=0.013, respectively). In addition, Hb level was inversely correlated with iPTH and serum phosphate (PO4) level (r=-0.54, P<0.001 and r=-0.47, P=0.005; respectively). Mineral disequilibrium is an important factor associated with anemia in ESA hyporesponsive CKD. Also, hyperphosphatemia and secondary hyperparathyroidism are significantly correlated with low Hb. As a result, we strongly suggest correction of mineral disequilibrium factors prior to performing bone marrow study.

Emerging Association Between Parathyroid Hormone and Anemia in Hemodialysis Patients

Anemia is a common complication of chronic kidney disease (CKD). There are various causes of renal anemia such as decreased production of erythropoietin, resistance to erythropoietin, shortened survival of red blood cells, and bone marrow fibrosis. Secondary hyperparathyroidism (SHPT) is a less recognized, but potentially significant cause of renal anemia in CKD patients. Parathyroid hormone (PTH) has been regarded as a uremic toxin that has multiple adverse effects, and its elevated levels have been associated with renal anemia in hemodialysis patients. Moreover, recent clinical studies have shown that the treatment of SHPT using either vitamin D receptor activators, calcimimetics, or parathyroidectomy leads to improvement of anemia, supporting the role of PTH in renal anemia. Emerging data have also indicated the involvement of bone-derived fibroblast growth factor 23 in renal anemia. This review summarizes recent insights into the role of PTH in renal anemia and discusses the importance of treating SHPT in improving the control of renal anemia in hemodialysis patients.

Effects of Secondary Hyperparathyroidism Treatment on Improvement in Anemia: Results from the MBD-5D Study

OBJECTIVES

Anemia is an important prognostic factor in hemodialysis patients. It has been reported that parathyroidectomy ameliorates anemia and reduces the requirement of postoperative erythropoiesis-stimulating agents. The objective of this study was to assess the effect of cinacalcet, which is considered as a pharmacological parathyroidectomy, on anemia in hemodialysis patients.

METHODS

We used data from a prospective cohort of Japanese hemodialysis patients with secondary hyperparathyroidism; the criteria were: intact parathyroid hormone concentrations ≥ 180 pg/mL or use of an intravenous or oral vitamin D receptor activator. All patients were cinacalcet-naïve at study enrollment. The main outcome measure was achievement of the target hemoglobin level (≥10.0 g/dL), which was measured repeatedly every 6 months. Cinacalcet exposure was defined as cumulative time since initiation. Both conventional longitudinal models and marginal structural models were adjusted for confounding factors.

RESULTS

Among 3,201 cinacalcet-naïve individuals at baseline, cinacalcet was initiated in 1,337 individuals during the follow up. Cinacalcet users were slightly younger; included more patients with chronic glomerulonephritis and fewer with diabetes; were more likely to have a history of parathyroidectomy; and were more often on activated vitamin D agents, phosphate binders, and iron supplements. After adjusting for both time-invariant and time-varying potential confounders, including demographics, comorbidities, comedications, and laboratory values, each additional 6-month duration on cinacalcet was associated with a 1.1-fold increase in the odds of achieving the target hemoglobin level.

CONCLUSIONS

Cinacalcet may improve anemia in chronic hemodialysis patients with secondary hyperparathyroidism, possibly through pathways both within and outside the parathyroid hormone pathways. Further investigations are warranted to delineate the roles of cinacalcet not only in the management of chronic kidney disease-mineral and bone disorder but also in anemia control.

Calcium-sensing receptor activation in chronic kidney disease: effects beyond parathyroid hormone control

Secondary hyperparathyroidism (SHPT) is an important complication of advanced chronic kidney disease (CKD). Cinacalcet, an allosteric modulator of the calcium-sensing receptor (CaSR) expressed in parathyroid glands, is the only calcimimetic approved to treat SHPT in patients on dialysis. By enhancing CaSR sensitivity for plasma extracellular calcium (Ca(2+)0), cinacalcet reduces serum parathyroid hormone, Ca(2+)0, and serum inorganic phosphorous concentrations, allowing better control of SHPT and CKD-mineral and bone disorders. Of interest, the CaSR also is expressed in a variety of tissues where its activation regulates diverse cellular processes, including secretion, apoptosis, and proliferation. Thus, the existence of potential off-target effects of cinacalcet cannot be neglected. This review summarizes our current knowledge concerning the potential role(s) of the CaSR expressed in various tissues in CKD-related disorders, independently of parathyroid hormone control.