Introduction:
Etelcalcetide, an intravenous calcimimetic agent, is approved for managing secondary hyperparathyroidism (sHPT) in adult haemodialysis (HD) patients. The recommended starting dose of etelcalcetide is 5mg three times a week. However, observational studies indicate that a lower initial dose (7.5-10mg/week) can effectively manage sHPT and be more cost-effective. This clinical audit aimed to evaluate the effectiveness of low accumulated etelcalcetide dose (LD) compared to standard dose (SD) within the first six months of etelcalcetide initiation in managing sHPT among HD patients in Singapore.
Methods:
The retrospective clinical audit included 263 HD patients managed by community haemodialysis centers in Singapore who received etelcalcetide continuously for six months, from August 2021 to July 2024. Only patients with complete data were considered; those who had a total parathyroidectomy within six months of etelcalcetide initiation were excluded. Patients were categorised into LD (≤250mg/6 month) and SD (>250mg/6 months) groups. The primary outcome was the absolute and percent change in serum parathyroid hormone (PTH) at six months. Secondary outcomes were absolute and percent changes in serum calcium, phosphate and alkaline phosphatase (SAP) levels at six months. Three regression models were constructed: Model 1 was unadjusted, Model 2 adjusted for age, gender, ethnicity, dialysis vintage, vascular access type, accumulated alfacalcidol dose, comorbidity and baseline laboratory parameters, and in Model 3, all variables in Model 2 were used to calculate the propensity score for inverse probability weighting (IPW), these variables were also adjusted in the weighted model.
Results:
159 patients (60.5%) received LD, while 104 (39.5%) received SD. The median age was 62.0 (Interquartile range (IQR): 53.5, 71.0). More females were in the LD group (LD: 78 (49.1%), SD: 37 (35.6%)). The median accumulated dose among the LD patients was 185 (IQR: 155-195) mg and that of the SD patients was 344 (IQR: 298-388) mg. Mean baseline PTH levels were higher in the SD group (LD: 119±41.1pmol/L, SD: 150±67.1pmol/L). Additionally, SD patients also had more alfacalcidol over six months, longer dialysis vintage and higher baseline SAP. After inverse probability weighing, the two groups were comparable for all baseline characteristics. Over the 6-month period, there were no significant differences between groups in reducing PTH, SAP and serum phosphate. However, SD patients showed higher absolute (0.27, 95% Confidence Interval (CI) 0.14-0.4 mg/dL) and percent reduction (2.65, 95% CI 1.23-4.06%) in calcium than LD patients across all the models. Limitation: Due to the small sample size and retrospective nature of this audit, the analysis's outcome should be further verified in larger prospective cohort studies.
Conclusions:
The audit demonstrated that low and standard etelcalcetide doses had comparable effects on PTH levels in patients undergoing HD. Based on specific patient characteristics, such as dialysis vintage, baseline PTH and SAP levels, and clinical assessment, initiating doses lower than the recommended amount can be considered.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.