Is controlling phosphorus by decreasing dietary protein intake beneficial or harmful in persons with chronic kidney disease?
GROUND: Dietary restrictions to control serum phosphorus, which are routinely recommended to persons with chronic kidney disease, are usually associated with a reduction in protein intake. This may lead to protein-energy wasting and poor survival. OBJECTIVE: We aimed to ascertain whether a decline in serum phosphorus and a concomitant decline in protein intake are associated with an increase in the risk of death. DESIGN: In a 3-y study (7/2001-6/2004) of 30 075 prevalent maintenance hemodialysis (MHD) patients, we examined changes in serum phosphorus and in normalized protein nitrogen appearance (nPNA), a surrogate of dietary protein intake, during the first 6 mo and the subsequent mortality. Four groups of MHD patients were defined on the basis of the direction of the changes in serum phosphorus and nPNA. RESULTS: Baseline phosphorus had a J-shaped association with mortality, whereas higher baseline nPNA was linearly associated with greater survival. Compared with MHD patients whose s
