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Published on: October 2, 2020
Effects of lowering dialysate calcium concentration on mineral metabolism and hemodynamic parameters in hemodialysis
Ahmed Alayoud1, Driss El Kabbaj, Mohammed Benyahia
1Service of Nephrology, Dialysis and Kidney Transplantation, Military Hospital Avicenne, Marrakech, Morocco. a_alayoud@yahoo.fr.
Insights
Reducing dialysate calcium to 1.5 mmol/L in hemodialysis patients prevented hypercalcemia and improved parathyroid hormone (PTH) levels. However, this change led to increased alfacalcidol use and more frequent hemodynamic issues like hypotension.
Area of Science:
- Nephrology
- Mineral Metabolism
- Cardiovascular Health
Background:
- Dialysate calcium concentration is a critical factor in hemodialysis, balancing bone health and cardiovascular risks.
- A concentration of 1.5 mmol/L has been proposed as a compromise, but its effects require further investigation.
Purpose of the Study:
- To evaluate the impact of reducing dialysate calcium concentration from 1.75 mmol/L to 1.5 mmol/L.
- To assess changes in mineral metabolism and hemodynamic parameters in hemodialysis patients.
Main Methods:
- A prospective study involving 52 hemodialysis patients over 9 months.
- Dialysate calcium concentration was reduced from 1.75 mmol/L to 1.5 mmol/L.
- Mineral metabolism markers and dialysis outcomes were monitored.
Main Results:
- Significant decrease in postdialytic serum calcium and a significant increase in intact parathyroid hormone (PTH).
- Increased requirement for oral alfacalcidol, with no changes in oral calcium carbonate or alkaline phosphatase.
- Reduced ultrafiltration rate and postdialysis systolic blood pressure, but increased frequency of intradialytic hypotension and cramps.
Conclusions:
- Lowering dialysate calcium to 1.5 mmol/L effectively prevents postdialytic hypercalcemia and stimulates PTH secretion.
- This adjustment necessitates increased alfacalcidol use and is associated with greater hemodynamic instability during dialysis.
Introduction:
It has been suggested that a dialysate calcium concentration of 1.5 mmol/L is a compromise between bone protection and cardiovascular risk. This study aimed to investigate the effect of reducing dialysate calcium concentration to 1.5 mmol/L on mineral metabolism and hemodynamic parameters.
Materials And Methods:
Dialysate calcium concentration was changed from 1.75 mmol/L to 1.5 mmol/L for 9 months and observed the effects on mineral metabolism and dialysis outcome parameters in 52 hemodialysis patients.
Results:
The results at 9 months demonstrated that postdialytic serum calcium level decreased significantly from 109 ± 7 mg/L to 102 ± 6 mg/L, intact parathyroid hormone (PTH) increased from 372 ± 52 pg/mL to 606 ± 80 pg/mL, and the oral alfacalcidol increased from 1.4 ± 0.3 µg/w to 3.3 ± 0.4 µg/w. In patients with low PTH levels, continuous increase of PTH was observed. There were no significant variation in the oral calcium carbonate dose and serum levels of alkaline phosphatase, predialytic calcium, and pre- and postdialytic phosphorus. The ultrafiltration rate and postdialysis systolic blood pressure were significantly lower after reducing the dialysate calcium concentration to 1.5 mmol/L. Intradialytic hypotension and cramps were more frequent with this dialysate calcium concentration.
Conclusions:
These findings demonstrated that a decrease in dialysate calcium concentration from 1.75 mmol/L to 1.5 mmol/L improved mineral metabolism by prevention of postdialytic hypercalcemia and releasing oversuppression of PTH, but it was associated with more use of oral alfacalcidol and more hemodynamic impairment.
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