Relationship between serum phosphorus and the progression of advanced chronic kidney disease

• Published in: Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia Vol. 31; no. 6; p. 707
• Main Authors: Caravaca, F, Villa, J, García de Vinuesa, E, Martínez del Viejo, C, Martínez Gallardo, R, Macías, R, Ferreira, F, Cerezo, I, Hernández-Gallego, R
• Format: Journal Article
• Language: English; Spanish
• Published: Spain 2011
• Subjects: Aged; Bicarbonates - blood; Biomarkers; Calcitriol - therapeutic use; Calcium - metabolism; Chelating Agents; Chronic Disease; Confounding Factors (Epidemiology); Disease Progression; Diuretics - therapeutic use; Female; Follow-Up Studies; Glomerular Filtration Rate; Humans; Hyperphosphatemia - epidemiology; Hyperphosphatemia - etiology; Kidney Diseases - blood; Kidney Diseases - complications; Kidney Diseases - drug therapy; Male; Middle Aged; Parathyroid Hormone - blood; Phosphorus - blood; Predictive Value of Tests; Prospective Studies
• ISSN: 1989-2284
• DOI: 10.3265/Nefrologia.pre2011.Sep.11089

High serum phosphorus (P) has been shown to be associated with a more rapid decline of renal function in patients with chronic kidney disease (CKD). The aim of this study was to determine whether time-averaged serum P levels are associated with the progression of renal failure adjusted for other potential confounders. A prospective observational study of 184 patients with pre-dialysis CKD, stages 3, 4 and 5 (mean GFR=15.2±5.6 ml/min/1.73 m2). The rate of decline in renal function was calculated as the slope of GFR. Median follow-up time was 303 days. Biochemical parameters were analysed as time-averaged concentrations. Multivariate linear regression analysis was used to assess the best determinants of serum P levels, and the relationship between the rate of decline of renal function and the study covariates. The best determinants of serum P levels were: GFR (beta = 0.477), female sex (beta = 0.106), serum calcium (beta = -0.274), serum albumin (beta = -0.112), serum bicarbonate (beta = -0.182), protein catabolic rate (beta = 0.144), and use of diuretics (beta = 0.180). The mean ± standard deviation (SD) slope of GFR was -0.198±0.376 ml/min/month. The best determinants of the slope of GFR were: proteinuria (beta = -0.462), serum P (beta = -0.440), and basal GFR (beta = -0.404). Total urinary P excretion was not significantly associated with the rate of decline of renal function. High serum P levels are strongly and independently associated with a more rapid decline of renal function in patients with advanced CKD.