LONG-TERM ORAL CALCIUM SUPPLEMENTATION REDUCES DIASTOLIC BLOOD-PRESSURE IN END-STAGE RENAL-DISEASE - A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY

Previous studies suggest that oral calcium supply reduces blood pressu re in patients with mild to moderate hypertension. The aim of this stu dy was to determine whether oral calcium supply reduces blood pressure in patients undergoing haemodialysis. The study was randomized, doubl e-blind, and placebo controlled. Eleven patients received two grams of calcium per day and 12 patients received placebo. Three patients (one from the calcium group and two from the placebo group) dropped out wi thin the first month. The groups were comparable at inclusion regardin g blood pressure, weight, and serum values. Blood pressure measurement s were auscultatory with a mercury manometer and diastolic blood press ure was measured as Korotkoff phase V. At inclusion a significant posi tive correlation between serum phosphate and blood pressure was found. After a study period of six months a significant reduction in diastol ic blood pressure was found between the two groups (p < 0.05), but no difference was found in systolic blood pressure. The reduction in dias tolic blood pressure was 6.9 mmHg of the pretreatment level in the cal cium group. In conclusion, the treatment of secondary hyperparathyroid ism with oral calcium gives good benefits in the regulation of diastol ic blood pressure. A well controlled phosphate homeostasis may also be of importance for the control of blood pressure in haemodialysis pati ents.