Influence of renin–angiotensin system on serum parathyroid hormone levels in uremic patients

Introduction The aim of this study was to investigate the factors influencing serum parathyroid (PTH) levels, including medications for treating chronic kidney disease–mineral and bone metabolism disorder (CKD-MBD) in patients with end-stage renal disease. Methods We enrolled 1,076 patients in nine Japanese facilities who had begun hemodialysis (HD) due to ESRD. We investigated the relationships between intact PTH (iPTH) levels and clinical parameters and medications just prior to beginning HD. Results Significant decreases in serum iPTH levels were seen in males, in the presence of diabetes mellitus (DM), and with administration of renin–angiotensin system inhibitors (RASIs). Significant correlations were found between serum calcium and iPTH levels. In the patients administered RASIs, there was a significant decrease in serum iPTH levels with DM, male gender, and administration of active vitamin D sterols (VDs) compared with those not administered RASIs, although serum-corrected calcium levels were not different. Multiple regression analysis found gender, age, presence of DM, and serum calcium and phosphate levels to be significant contributing factors. In addition, administration of angiotensin II receptor blockers (ARBs) may also be a contributing factor to iPTH levels at the beginning HD ( p = 0.050). Conclusions In this study, serum iPTH levels were related to administration of ARBs besides gender, age, the presence of DM and serum calcium levels. Our study suggests that the RA system involve serum iPTH levels in uremic patients.