Efficacy of low-dose cinacalcet on alternate days for the treatment of secondary hyperparathyroidism in hemodialysis patients: a single-center study

Pre-operative Cinacalcet Administration Reduces Immediate Post-operative Hypocalcemia Following Total Parathyroidectomy in Severe Renal Hyperparathyroidism

BACKGROUND

In severe renal hyperparathyroidism (RHPT), whether administrating Cinacalcet before total parathyroidectomy can reduce post-operative hypocalcemia remains unclear. We compared post-operative calcium kinetics between those who took Cinacalcet before surgery (Group I) and those who did not (Group II).

METHODS

Patients with severe RHPT (defined by PTH ≥ 100 pmol/L) who underwent total parathyroidectomy between 2012 and 2022 were analyzed. Standardized peri-operative protocol of calcium and vitamin D supplementation was followed. Blood tests were performed twice daily in the immediate post-operative period. Severe hypocalcemia was defined as serum albumin-adjusted calcium < 2.00 mmol/L.

RESULTS

Among 159 patients who underwent parathyroidectomy, 82 patients were eligible for analysis (Group I, n = 27; Group II, n = 55). Demographics and PTH levels before Cinacalcet administration were comparable (Group I: 169 ± 49 pmol/L vs Group II: 154 ± 45, p = 0.209). Group I had significantly lower pre-operative PTH (77 ± 60 pmol/L vs 154 ± 45, p < 0.001), higher post-operative calcium (p < 0.05), and lower rate of severe hypocalcemia (33.3% vs 60.0%, p = 0.023). Longer duration of Cinacalcet use correlated with higher post-operative calcium levels (p < 0.05). Cinacalcet use for > 1 year resulted in fewer severe post-operative hypocalcemia than non-users (p = 0.022, OR 0.242, 95% CI 0.068-0.859). Higher pre-operative ALP independently correlated with severe post-operative hypocalcemia (OR 3.01, 95% CI 1.17-7.77, p = 0.022).

CONCLUSION

In severe RHPT, Cinacalcet led to significant drop in pre-operative PTH, higher post-operative calcium levels, and less frequent severe hypocalcemia. Longer duration of Cinacalcet use correlated with higher post-operative calcium levels, and the use of Cinacalcet for > 1 year reduced severe post-operative hypocalcemia.

The Effectiveness of Alternate-day Cinacalcet Therapy for Secondary Hyperparathyroidism in Noncompliant Hemodialysis Patients

Chronic kidney disease (CKD) is defined as an abnormality of the kidney's structure or function that is present for more than 3 months. Secondary hyperparathyroidism is a consequence of CKD, which eventuates with a decrease in the glomerular filtration rate. This study aimed to evaluate the effectiveness of alternate-day cinacalcet in noncompliant dialysis patients compared with a daily dose. The effects on the levels of intact parathyroid hormone (iPTH), calcium, and phosphorus were measured, and the compliance of patients with our protocol was observed. We followed the patients' (n = 134) iPTH levels every 3 months and their serum calcium and phosphorous monthly for 6 months and compared the results with 6 months of data from patients receiving daily doses of cinacalcet. The patients' mean age was 49.54 ± 16.17 years, the mean duration of dialysis was 6.44 ± 5.10 years, and 37.3% had diabetic nephropathy. The mean dose of alternate-day cinacalcet was 61.92 ± 26.59 mg. The level of iPTH before and after the change was 924.63 ± 474.132 pg/mL and 787.87 ± 496.49 pg/mL, respectively (P = 0.001), and the mean serum calcium level before and after was 8.56 ± 1.91 mg/dL and 8.85 ± 1.25 mg/dL, respectively (P = 0.035). The level of serum phosphorous before and after the change was 4.81 ± 1.32 mg/dL and 5.08 ± 2.3 mg/dL, respectively (P = 0.204). Cinacalcet produced significant reductions in iPTH with intermittent (three times per week) doses and thus was more cost-effective and had better compliance.

A single-centre retrospective analysis of cinacalcet therapy in primary hyperparathyroidism

Primary hyperparathyroidism (pHPT) is a common endocrine disorder that can be cured by parathyroidectomy; patients unsuitable for surgery can be treated with cinacalcet. Availability of surgery may be reduced during COVID-19, and cinacalcet can be used as bridging therapy. In this single-centre retrospective analysis, we investigated the utility and safety of cinacalcet in patients with pHPT receiving cinacalcet between March 2019 and July 2020, including pre-parathyroidectomy bridging. We reviewed and summarised the published literature. Cinacalcet dosages were adjusted by endocrinologists to achieve target calcium < 2.70 mmol/L. Eighty-six patients were identified, with the most achieving target calcium (79.1%) with a mean dose of 39.4 mg/day (±17.1 mg/day) for a median duration of 35 weeks (1-178 weeks). Calcium was normalised in a median time of 5 weeks. The majority of patients commenced cinacalcet of 30 mg/day (78 patients) with the remainder at 60 mg/day (8 patients). Forty-seven patients commencing lower dose cinacalcet (30 mg/day) achieved target calcium without requiring 60 mg/day. Baseline PTH was significantly higher in patients requiring higher doses of cinacalcet. 18.6% of patients reported adverse reactions and 4.7% discontinued cinacalcet. Patients treated with cinacalcet pre-parathyroidectomy required a higher dose and fewer achieved target calcium compared to medical treatment with cinacalcet alone. Post-operative calcium was similar to patients who were not given pre-parathyroidectomy cinacalcet. In summary, cinacalcet at an initial dose of 30 mg/day is safe and useful for achieving target calcium in patients with symptomatic or severe hypercalcaemia in pHPT, including those treated for pre-parathyroidectomy. We propose a PTH threshold of >30 pmol/L to initiate at a higher dose of 60 mg/day.

Therapeutic experience of severe and recurrent secondary hyperparathyroidism in a patient on hemodialysis for 18 years: A case report

INTRODUCTION

For patients with refractory secondary hyperparathyroidism (SHPT), parathyroidectomy (PTX) has received increasing attention. However, evidence-based medicine shows that there is still controversy regarding surgical methods, efficacy, and safety. We retrospectively analyzed the process of diagnosis and treatment in one patient with severe SHPT and long-term chronic renal failure (CRF), so as to further improve the therapeutic effect.

CASE PRESENTATION

A 61-year-old female with SHPT and CRF manifested as no urine for 18 years, underwent PTX 4 times since September 2010, with satisfactory final recovery. The first operation involved resection of 3 parathyroid glands in the normal position; the second operation involved removal of an ectopic parathyroid gland, combined with parathyroid gland autotransplantation; the third operation was performed to resect suspected recurrent parathyroid gland; the fourth operation involved partial excision of the autotransplanted parathyroid glands.

CONCLUSION

Accurate preoperative localized diagnosis and optimal surgical approach play key roles in the prevention and treatment of SHPT; postoperative recurrence of SHPT caused by ectopic or autotransplanted parathyroid gland should receive more attention.