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Long-term dialysis with low-calcium solution (1.0 mmol/L) in CAPD: effects on bone mineral metabolism. Collaborators of the Multicenter Study Group.
Perit Dial Int. 1996 May-Jun; 16(3):260-8.PD

Abstract

OBJECTIVE

Peritoneal dialysate solutions with conventionally high-calcium (Ca) concentrations (1.75 mmol/L) are now widely replaced by solutions with a lower, more physiological calcium content to prevent hypercalcemia in patients treated with oral calcium-containing phosphate binders and/or calcitriol. While there is still debate on how far the dialysate calcium should be lowered (1.25 mmol/L or less), little information is available concerning the effects of a long-term treatment with low-calcium solutions on secondary hyperparathyroidism and bone mineral metabolism in general.

DESIGN

A prospective, randomized, controlled multicenter study to compare the effects of low-calcium (LCa, dialysate calcium 1.0 mmol/L) versus standard-calcium dialysate solution (SCa, dialysate calcium 1.75 mmol/L) on bone mineral metabolism in continuous ambulatory peritoneal dialysis (CAPD) patients over 2 years of treatment.

SETTING

Nephrology and dialysis units of primary and tertiary hospitals in Germany and Switzerland.

PATIENTS

All CAPD patients in the participating centers between 18 and 80 years of age, stable on CAPD for at least 1 month, free of aluminium bone disease or prior parathyroidectomy were invited to enter the study. Sixty-four patients could be randomly allotted to LCa (n = 35) or SCa (n = 29) treatment in a 2-year protocol; 34 finished the study as planned.

INTERVENTIONS

Calcium carbonate (CaCO3) was given as oral phosphate binder to maintain serum phosphate < 2.0 mmol/L. If hypercalcemia supervened, CaCO3 was exchanged stepwise for aluminium hydroxide (Al(OH)3), until normocalcemia was obtained. Patients received calcitriol (0.25 microgram/day per os) if parathyroid hormone (PTH) exceeded the upper limit of normal by a factor of 2 or more.

MAIN OUTCOME MEASURES

We assessed total and ionized serum calcium, phosphate, serum aluminum, alkaline phosphatase, osteocalcin, PTH (intact molecule), and phosphate binder intake at regular intervals. Measurements of bone mineral density and hand skeleton x-rays were obtained at the start and after 6 months and 2 years, respectively.

RESULTS

With LCa, mean total and ionized serum calcium levels were within the normal range (total Ca: 2.0-2.6 mmol/L; ionized Ca: 1.19-1.32 mmol/L), but throughout the treatment period were significantly lower than with SCa. The incidence of hypercalcemia (> 2.8 mmol/L) was three times higher in patients on SCa, despite the significantly higher amount of Al(OH)3 and less CaCO3 given in this group. In parallel, serum aluminum increased with SCa throughout the study, whereas it was slowly decreasing with LCa. Median PTH levels remained stable at about two times the upper limit of normal over the 2 years of study with LCa. However, 23% of the patients on LCa developed severe hyperparathyroidism, with PTH levels exceeding ten times the upper limit of normal compared to only 10.3% of the patients on SCa. With SCa, median PTH decreased towards near normal levels. Alkaline phosphatase and serum osteocalcin correlated positively with PTH levels. Bone mineral density was in the lower normal range in both groups and remained unchanged at the end of the study. Skeletal x-ray films showed only minor alterations in very few patients in both groups with no correlation to serum PTH or treatment modality.

CONCLUSION

In CAPD patients low-calcium dialysate solutions can be used successfully over prolonged periods of time with stable control of serum calcium. The risk of hypercalcemia resulting from calcium-containing phosphate binders and the need to use aluminum-containing phosphate binders is markedly diminished. However, there is a certain risk that severe secondary hyperparathyroidism with long-term LCa therapy will develop, even if normocalcemia is maintained. Thus, LCa dialysis requires close and continuous monitoring of PTH and bone metabolism.

Authors+Show Affiliations

Department of Internal Medicine, University Hospital, Zürich, Switzerland.No affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Multicenter Study
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8761540

Citation

Weinreich, T, et al. "Long-term Dialysis With Low-calcium Solution (1.0 mmol/L) in CAPD: Effects On Bone Mineral Metabolism. Collaborators of the Multicenter Study Group." Peritoneal Dialysis International : Journal of the International Society for Peritoneal Dialysis, vol. 16, no. 3, 1996, pp. 260-8.
Weinreich T, Ritz E, Passlick-Deetjen J. Long-term dialysis with low-calcium solution (1.0 mmol/L) in CAPD: effects on bone mineral metabolism. Collaborators of the Multicenter Study Group. Perit Dial Int. 1996;16(3):260-8.
Weinreich, T., Ritz, E., & Passlick-Deetjen, J. (1996). Long-term dialysis with low-calcium solution (1.0 mmol/L) in CAPD: effects on bone mineral metabolism. Collaborators of the Multicenter Study Group. Peritoneal Dialysis International : Journal of the International Society for Peritoneal Dialysis, 16(3), 260-8.
Weinreich T, Ritz E, Passlick-Deetjen J. Long-term Dialysis With Low-calcium Solution (1.0 mmol/L) in CAPD: Effects On Bone Mineral Metabolism. Collaborators of the Multicenter Study Group. Perit Dial Int. 1996 May-Jun;16(3):260-8. PubMed PMID: 8761540.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Long-term dialysis with low-calcium solution (1.0 mmol/L) in CAPD: effects on bone mineral metabolism. Collaborators of the Multicenter Study Group. AU - Weinreich,T, AU - Ritz,E, AU - Passlick-Deetjen,J, PY - 1996/5/1/pubmed PY - 1996/5/1/medline PY - 1996/5/1/entrez SP - 260 EP - 8 JF - Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis JO - Perit Dial Int VL - 16 IS - 3 N2 - OBJECTIVE: Peritoneal dialysate solutions with conventionally high-calcium (Ca) concentrations (1.75 mmol/L) are now widely replaced by solutions with a lower, more physiological calcium content to prevent hypercalcemia in patients treated with oral calcium-containing phosphate binders and/or calcitriol. While there is still debate on how far the dialysate calcium should be lowered (1.25 mmol/L or less), little information is available concerning the effects of a long-term treatment with low-calcium solutions on secondary hyperparathyroidism and bone mineral metabolism in general. DESIGN: A prospective, randomized, controlled multicenter study to compare the effects of low-calcium (LCa, dialysate calcium 1.0 mmol/L) versus standard-calcium dialysate solution (SCa, dialysate calcium 1.75 mmol/L) on bone mineral metabolism in continuous ambulatory peritoneal dialysis (CAPD) patients over 2 years of treatment. SETTING: Nephrology and dialysis units of primary and tertiary hospitals in Germany and Switzerland. PATIENTS: All CAPD patients in the participating centers between 18 and 80 years of age, stable on CAPD for at least 1 month, free of aluminium bone disease or prior parathyroidectomy were invited to enter the study. Sixty-four patients could be randomly allotted to LCa (n = 35) or SCa (n = 29) treatment in a 2-year protocol; 34 finished the study as planned. INTERVENTIONS: Calcium carbonate (CaCO3) was given as oral phosphate binder to maintain serum phosphate < 2.0 mmol/L. If hypercalcemia supervened, CaCO3 was exchanged stepwise for aluminium hydroxide (Al(OH)3), until normocalcemia was obtained. Patients received calcitriol (0.25 microgram/day per os) if parathyroid hormone (PTH) exceeded the upper limit of normal by a factor of 2 or more. MAIN OUTCOME MEASURES: We assessed total and ionized serum calcium, phosphate, serum aluminum, alkaline phosphatase, osteocalcin, PTH (intact molecule), and phosphate binder intake at regular intervals. Measurements of bone mineral density and hand skeleton x-rays were obtained at the start and after 6 months and 2 years, respectively. RESULTS: With LCa, mean total and ionized serum calcium levels were within the normal range (total Ca: 2.0-2.6 mmol/L; ionized Ca: 1.19-1.32 mmol/L), but throughout the treatment period were significantly lower than with SCa. The incidence of hypercalcemia (> 2.8 mmol/L) was three times higher in patients on SCa, despite the significantly higher amount of Al(OH)3 and less CaCO3 given in this group. In parallel, serum aluminum increased with SCa throughout the study, whereas it was slowly decreasing with LCa. Median PTH levels remained stable at about two times the upper limit of normal over the 2 years of study with LCa. However, 23% of the patients on LCa developed severe hyperparathyroidism, with PTH levels exceeding ten times the upper limit of normal compared to only 10.3% of the patients on SCa. With SCa, median PTH decreased towards near normal levels. Alkaline phosphatase and serum osteocalcin correlated positively with PTH levels. Bone mineral density was in the lower normal range in both groups and remained unchanged at the end of the study. Skeletal x-ray films showed only minor alterations in very few patients in both groups with no correlation to serum PTH or treatment modality. CONCLUSION: In CAPD patients low-calcium dialysate solutions can be used successfully over prolonged periods of time with stable control of serum calcium. The risk of hypercalcemia resulting from calcium-containing phosphate binders and the need to use aluminum-containing phosphate binders is markedly diminished. However, there is a certain risk that severe secondary hyperparathyroidism with long-term LCa therapy will develop, even if normocalcemia is maintained. Thus, LCa dialysis requires close and continuous monitoring of PTH and bone metabolism. SN - 0896-8608 UR - https://www.unboundmedicine.com/medline/citation/8761540/Long_term_dialysis_with_low_calcium_solution__1_0_mmol/L__in_CAPD:_effects_on_bone_mineral_metabolism__Collaborators_of_the_Multicenter_Study_Group_ L2 - https://medlineplus.gov/bonedensity.html DB - PRIME DP - Unbound Medicine ER -