Bisphosphonate Use in Patients Undergoing Dialysis

Elimination of intravenous alendronate by hemodialysis: A kinetic study

INTRODUCTION

The potential utility of intravenous alendronate for the treatment of osteoporosis in hemodialysis patients was recently reported. However, the pharmacokinetics of intravenous alendronate in patients on hemodialysis is not clear.

METHODS

Six hemodialysis patients (mean age, 80.5 years) with osteoporosis who had received intravenous alendronate prior to the study were enrolled. The participants received a 30-min infusion of 900-μg alendronate intravenously at the beginning of the dialysis session. The blood flow rate (Qb) and dialysate flow rate (Qd) were set at 200 mL/min and 500 mL/min, respectively. All patients used the same dialyzer (1.5-m² polysulfone membrane). At the completion of administration, plasma and dialysate samples were collected, and alendronate concentrations were determined using metal-free high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS).

RESULTS

The plasma arterial alendronate concentration was 150.9 ± 46.09 ng/mL. It decreased through the dialyzer to 76.1 ± 34.1 ng/mL (venous alendronate concentration). Mean alendronate clearance was 113.9 ± 25.6 mL/min. Mean alendronate removal by hemodialysis, measured by the difference in arterial-venous concentrations, was 51.8%.

CONCLUSIONS

Fifty percent of intravenous alendronate was removed by hemodialysis, which is nearly equal to elimination of alendronate in patients with normal renal function. The elimination by hemodialysis would decrease the risk of excessive accumulation in bone. UMIN 000027182.

Effects of denosumab on bone metabolism and bone mineral density in kidney transplant patients: a systematic review and meta-analysis

OBJECTIVE

The use of immunosuppressive agents, especially glucocorticoids, are associated with increased risks of bone loss in kidney transplant patients. Denosumab, a potent antiresorptive agent, has been shown to increase bone mineral density (BMD) in patients with CKD. However, its effects on bone metabolism and BMD in kidney transplant patients remain unclear.

METHODS

A literature search was conducted using MEDLINE, EMBASE, and Cochrane Database from inception through April 2018 to identify studies evaluating denosumab's effect on changes in bone metabolism and BMD from baseline to post-treatment course in kidney transplant patients. Study results were pooled and analyzed utilizing random-effects model. The protocol for this systematic review is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42018095055).

RESULTS

Five studies (a clinical trial and four cohort studies) with a total of 162 kidney transplant patients were identified. The majority of patients had a baseline eGFR ≥ 30 mL/min/1.73 m². After treatment (≥ 6 to 12 months), there were significant increases in BMD with standardized mean differences (SMDs) of 3.26 (95% CI 0.88-5.64) and 1.83 (95% CI 0.43 to 3.22) for lumbar spine and femoral neck, respectively. There were also significant increases in T scores with SMDs of 0.92 (95% CI 0.58 to 1.25) and 1.14 (95% CI 0.17 to 2.10) for lumbar spine and femoral neck, respectively. After treatment, there were no significant changes in serum calcium (Ca) or parathyroid hormone (PTH) from baseline to post-treatment course (≥ 6 months) with mean differences (MDs) of 0.52 (95% CI, - 0.13 to 1.16) mmol/L and - 13.24 (95% CI, - 43.85 to 17.37) ng/L, respectively. The clinical trial data demonstrated more asymptomatic hypocalcemia in the denosumab (12 episodes in 39 patients) than in the control (1 episode in 42 patients) group. From the cohort studies, the pooled incidence of hypocalcemia following denosumab treatment was 1.7% (95% CI 0.4 to 6.6%). All reported hypocalcemic episodes were mild and asymptomatic, but the majority of patients required Ca and vitamin D supplements.

CONCLUSION

Among kidney transplant patients with good allograft function, denosumab effectively increases BMD and T scores in the lumbar spine and femur neck. From baseline to post-treatment, there are no differences in serum Ca and PTH. However, mild hypocalcemia can occur following denosumab treatment, requiring monitoring and titration of Ca and vitamin D supplements.

Hypocalcemia and bone mineral density changes following denosumab treatment in end-stage renal disease patients: a meta-analysis of observational studies

The incidence of hypocalcemia and bone mineral density (BMD) changes in end-stage renal disease (ESRD) patients on denosumab remains unclear. We performed this meta-analysis to assess the incidence of denosumab-associated hypocalcemia and effects of denosumab on BMD in ESRD patients. A literature search was conducted using MEDLINE, EMBASE, and Cochrane Database from inception through November 2017 to identify studies evaluating incidence of denosumab-associated hypocalcemia and changes in serum calcium, phosphate, alkaline phosphatase (ALP), parathyroid hormone (PTH), and BMD from baseline to post-treatment course of denosumab in ESRD patients. Study results were pooled and analyzed using a random-effect model. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42017081074). Six observational studies with a total of 84 ESRD patients were enrolled. The pooled estimated incidence of hypocalcemia during denosumab treatment was 42% (95% CI 29-55%, I² = 0%). Hypocalcemia occurred approximately 7 to 20 days after the first dose and reached nadir of low calcium levels in the first 2 weeks up to 2 months. However, there were no significant changes in serum calcium or phosphate from baseline to post-treatment course (≥ 3 months after treatment) with mean differences [MDs] of 0.20 mg/dL (95% CI, - 0.30 to 0.69 mg/dL) and - 0.10 mg/dL (95% CI, - 0.70 to 0.49 mg/dL). There were significant reductions in ALP and PTH levels with standardized mean differences (SMDs) of - 0.65 (95% CI - 1.13 to - 0.16) and - 1.89 (95% CI - 3.44 to - 0.34), respectively. There were significant increases in T-scores with MDs of 0.39 (95% CI 0.10 to 0.69) and 0.79 (95% CI 0.60 to 0.98) for lumbar spine and femoral neck, respectively. Our study demonstrates the estimated incidence of denosumab-associated hypocalcemia in dialysis patients of 42%. From baseline to post-treatment course, although there are no differences in serum calcium and phosphate, our findings suggest significant reductions in ALP and PTH and a significant increase in BMD. Currently, denosumab should not be considered as the treatment of choice in ESRD patients until more safety and efficacy data are available.

Denosumab for treatment of immobilization-related hypercalcemia in a patient with end-stage renal disease

The efficacy and safety of denosumab for the treatment of immobilization-related hypercalcemia in end-stage renal disease remain uncertain. We describe the case of a hemodialysis patient with immobilization-related hypercalcemia who was successfully treated with denosumab. A 79-year-old man admitted for hemodialysis after sustaining an acute kidney injury developed immobilization-related hypercalcemia due to the impairment resulting from an acute myocardial infarction, acute heart failure, and catheter-related bloodstream infection. After admission, the patient's corrected serum calcium rose to 12.9 from 8.8 mg/dL. A bisphosphonate (alendronate) was administered, but it was ineffective. Subsequently, treatment with denosumab proved to be effective and his corrected serum calcium level declined to 9.3 mg/dL within 1 week. Hypocalcemia, which is an adverse effect of denosumab, was prevented using active vitamin D and calcium supplementation, and his calcium level stabilized. Thus, our case demonstrates that denosumab is a viable therapeutic option for dialysis patients experiencing immobilization-related hypercalcemia.

Arteriosclerosis and vascular calcification: causes, clinical assessment and therapy

BACKGROUND

Arteriosclerosis is a pathological, structural (media vascular calcification) and physiological (modified vascular smooth vessel cells; increased arterial stiffness) alteration of the vessel wall. Through improved assessment methods (functional and imaging), it has become a well-known phenomenon in recent decades. However, its clinical importance was underestimated until recently.

MATERIALS AND METHODS

Currently available English-speaking data about conditions/diseases associated with arteriosclerosis, its clinical sequels, available diagnostic procedures and therapeutic modalities were reviewed and summarized.

RESULTS

In recent decades, emerging data have brought about a better understanding of causes and consequences of arteriosclerosis and highlight its growing clinical impact.

CONCLUSION

Although arteriosclerosis showed an independent clinical impact on cardiovascular morbidity and mortality, especially in patients with chronic kidney disease/end-stage renal disease (CKD/ESRD) and diabetes mellitus, convincing clinical therapy concepts are not available until now. The establishment of novel therapeutic strategies derived from basic research is strongly needed.