Changes and Influencing Factors of Urinary Phosphorus Excretion in Patients with Different Stages of Chronic Kidney Disease.

Abstract

The aim of the study was to explore the changes and the possible influencing factors of phosphorus excretion in chronic kidney disease (CKD) patients. A database with 204 patients who met the CKD diagnostic criteria was established. Clinical data, including 24-hour urine phosphorus excretion (24-hour UPE), were collected. The demographic and clinical characteristics of CKD patients in different stages and the changes in serum phosphorus (P) and 24-hour UPE with renal function were studied. After exploring the factors influencing 24-hour UPE by multiple linear regression analysis, the effects of gender on 24-hour UPE was assessed. Among 204 patients, there were significant differences in serum calcium (Ca), P, 24-hour UPE, intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D [25(OH)-VD] among different CKD stages. Twenty-four-hour UPE fluctuated greatly, but serum P was relatively stable, which was > 1.46 mmol/L at an estimated glomerular filtration rate (eGFR) < 10 mL/minute/1.73 m2. Male gender (β = 3.42, p < 0.00) and eGFR (β = 0.06, p < 0.00) were related to 24-hour UPE, while age, body weight, albumin (ALB), iPTH, and serum P were not related to 24-hour UPE according to regression analysis. There were significant differences in 24-hour UPE and serum P between males and females. Urinary phosphorus excretion decreased with decreasing renal function in CKD patients. Urinary phosphorus excretion might be affected by eGFR and gender.