Clinical Evaluation of Niacin in Hemodialysis Patients with Hyperphosphatemia as Adjuvant to Calcium Carbonate

Abstract

Background: The complications of End Stage Renal Disease ESRD attributed to high morbidity and mortality such as hyperphosphatemia and vascular disease. Vascular smooth muscle cells (VSMCs) are sensitive to elevation in serum phosphate levels and have the ability to modify their functions in response to this   elevation through h many processes that promote calcification. Vascular calcification is highly correlated with the major events of cardiovascular mortality which are included heart failure, sudden cardiac death, and ischemic heart disease. The control of hyperphosphatemia in HD patients remains poor in spite of the effectiveness of all the available phosphate binders. However, calcium based binder may promote the aggravation of vascular calcification while Aluminum- based binder associated with osteomalacia, and encephalopathy. Calcium/aluminum free phosphate binder may cause gastrointestinal adverse effect in addition to their high cost of treatment. The active phosphate transport inhibitors are the newest interesting agents in the management of hyperphosphatemia alone or as add-on therapy to the existing phosphate binders. Niacin is one of this novel drug classes that has been demonstrated to show promising therapeutic potential in the treatment of hyperphosphatemia in HD patients. Aim of study: This study is designed to evaluate the efficacy of niacin as adjuvant therapy to calcium carbonate (as a phosphate binder) in hemodialysis patients. Method: In this prospective, randomized interventional study, 56 patients confirmed with end stage renal disease (ESRD) and hyperphosphatemia on regular hemodialysis were included. Only 40 patients completed the study and were classified randomly into two groups: group (1); composed of 19 patients who received 1500 mg/day of calcium carbonate tablets, and group (2); composed 21 patients who received 1500 mg/day calcium carbonate tablets plus niacin both for 2 months’ duration. Blood sample was taken thrice, at baseline, after 1 month and at the end of month 2 for measurement of serum study parameters: (inorganic phosphorus (Pi), calcium (Ca), Calcium-Phosphorus product (Ca x P) . Results: Results of this study showed that the patients who administered orally niacin as adjuvant to calcium had the superiority over using calcium alone in the reduction of serum phosphorus level (-20.3% and -13.5%) respectively after 2 months of treatment in respect to baseline levels. Meanwhile, there was a marked increase in serum Ca level in both groups after 2 months of treatment however, it was non-significant. In addition, treatment with combination of calcium and niacin resulted in more reduction in serum (Ca x P) product level at the end of study than with calcium alone compared to baseline, nevertheless the change was non-significant. Conclusion: Administration of niacin for hemodialysis patients is an effective strategy for reducing the serum levels of inorganic phosphorus and calcium-phosphorus product which may lead to reduce the risks of cardiovascular diseases associated with hyperphosphatemia.