Effectiveness of lanthanum carbonate treatment used in combination with other phosphate binders in peritoneal dialysis patients

OBJECTIVE

Phosphate binders are used in the treatment of hyperphosphatemia in peritoneal dialysis (PD) patients. An ideal phosphate binder for long-term use must be effective with little or no side effects. We evaluated the long-term efficacy and side effects of lanthanum carbonate (LaC) used in combination with other phosphate binders in PD patients.

PATIENTS

The subjects of this retrospective study were 30 PD patients who received LaC at Kyushu University. The effect of LaC on various biochemical parameters (serum phosphate, calcium and parathyroid hormone), daily dose of other phosphate binders, gastrointestinal side effects, and nutritional status were determined during the 24-week treatment. We also evaluated the rate of achievement of the Japanese Society of Dialysis Treatment guidelines for secondary hyperparathyroidism and used multivariate analysis to determine the factors associated with the efficacy of LaC.

RESULTS

LaC (960 ± 412 mg/day) reduced serum phosphate from 6.2 to 5.3 mg/dL. The rate of achievement of the guideline target improved after 24 weeks of LaC treatment. The dose of other phosphate binders and dialysis volume remained unchanged during the treatment. Although 53% of patients experienced at least one gastrointestinal side effect, LaC treatment did not affect the nutritional status, and none of the patients discontinued LaC. Multivariate analysis identified low stature, old age and high baseline total creatinine clearance as significant factors that determine the effectiveness of LaC in PD patients.

CONCLUSION

Low dose LaC treatment used in combination with other phosphate binders improved serum phosphate control with tolerable gastrointestinal symptoms in PD patients.

Hyperphosphataemia in renal failure: causes, consequences and current management

Hyperphosphataemia is prevalent among chronic renal failure and dialysis patients. It is known to stimulate parathyroid hormone and suppress vitamin D3 production, thereby inducing hyperparathyroid bone disease. In addition, it may independently contribute to cardiac causes of death through increased myocardial calcification and enhanced vascular calcification. Hyperphosphataemia is also associated with cardiac microcirculatory abnormalities. Therefore, phosphate control is of prime importance. It is important to control phosphate levels early in the course of chronic renal failure in order to avoid and treat secondary hyperparathyroidism, and cardiovascular and soft tissue calcifications. Dietetic restrictions are often difficult to follow long term. Because of its large sphere of hydration and the complex kinetics of phosphate elimination, phosphate is not easily removed by dialysis. Long, slow dialysis may be effective, but this needs logistics and acceptance by patients. Thus, oral phosphate binders are generally required to control serum levels. None of the existing phosphate binding agents is truly satisfactory. Aluminium-containing agents are highly efficient but many clinicians have abandoned their use because of the potential toxicity. Despite of the wide use of calcium-containing agents, there was a link with hypercalcaemia and soft tissue calcifications. Novel phosphate binders in the form of polyallylamine hydrochloride, polyuronic acid derivatives and lanthanum carbonate appear promising. In this review, we discuss causes of hyperphosphataemia, pathological consequences and modalities of treatment.