Department of Cardiology, Queen Elizabeth Hospital, Birmingham and University of Birmingham, Birmingham, UK.
Nephrol Dial Transplant. 2011 Aug;26(8):2576-82. doi: 10.1093/ndt/gfq787. Epub 2011 Jan 19.
The rate of decline in kidney function is a powerful predictor of cardiovascular risk in patients with chronic kidney disease (CKD). Serum phosphate and increased arterial stiffness are associated with elevated cardiovascular risk in CKD and the general population. We sought to determine whether serum phosphate and markers of arterial stiffness predict progression of renal dysfunction in patients with early CKD.
Two hundred and twenty-five patients with Stage II-IV CKD were prospectively followed up at University Hospital Birmingham. Serum phosphate was measured at baseline and arterial stiffness was determined through measurement of aortic pulse wave velocity (PWV) and augmentation index (AIx). Progression of renal dysfunction was defined as the slope of estimated glomerular filtration rate (eGFR) against time. We determined the associations between possible predictors and rate of progression and also examined a combined end point of start of dialysis or ≥ 25% decline in eGFR.
Mean baseline eGFR was 43 ± 19 mL/min/1.73 m(2) and serum phosphate 1.22 ± 0.27 mmol/L. Median follow-up was 924 days. Serum phosphate independently predicted a greater decline in eGFR; a 1 mmol/L increment in serum phosphate was associated with a 0.34 mL/min/month steeper decline (P = 0.02). Brachial and aortic systolic pressure independently predicted the rate of renal function decline but aortic PWV and AIx had no significant influence. Forty-one patients (18%) reached the combined end point; serum phosphate was significantly higher in this group (1.32 ± 0.36 versus 1.19 ± 0.24 mmol/L, P = 0.04) and was an independent predictor for the combined end point.
Serum phosphate independently predicts decline in renal function in early CKD. Further studies are required to determine the mechanisms involved and to investigate the potential benefits of phosphate lowering on preserving kidney function.
肾功能的下降速度是慢性肾脏病（CKD）患者心血管风险的有力预测指标。血清磷酸盐和动脉僵硬度的增加与 CKD 和普通人群中的心血管风险升高有关。我们试图确定血清磷酸盐和动脉僵硬度标志物是否可预测早期 CKD 患者肾功能障碍的进展。
225 名 II-IV 期 CKD 患者在伯明翰大学医院前瞻性随访。在基线时测量血清磷酸盐，通过测量主动脉脉搏波速度（PWV）和增强指数（AIx）来确定动脉僵硬度。肾功能障碍的进展定义为估计肾小球滤过率（eGFR）随时间的斜率。我们确定了可能的预测因素与进展速度之间的关系，并检查了透析开始或 eGFR 下降≥25%的联合终点。
平均基线 eGFR 为 43±19mL/min/1.73m2，血清磷酸盐为 1.22±0.27mmol/L。中位随访时间为 924 天。血清磷酸盐独立预测 eGFR 下降更大；血清磷酸盐增加 1mmol/L，eGFR 下降速度加快 0.34mL/min/月（P=0.02）。肱动脉和主动脉收缩压独立预测肾功能下降速度，但主动脉 PWV 和 AIx 无显著影响。41 名患者（18%）达到联合终点；该组血清磷酸盐明显较高（1.32±0.36 与 1.19±0.24mmol/L，P=0.04），且是联合终点的独立预测因子。
血清磷酸盐独立预测早期 CKD 患者肾功能下降。需要进一步研究以确定所涉及的机制，并研究降低磷酸盐对保护肾功能的潜在益处。
