Background: Serum phosphorus is thought to be an important risk factor for the progression of chronic kidney disease (CKD). However, the association of serum phosphorus with disease progression in patients with different causes of kidney diseases remains to be elucidated.
Objectives: The aim of this study was to estimate the effect of serum phosphorus on disease progression in 2 cohorts of CKD with different causes.
Material and methods: A total of 591 patients with diabetic nephropathy and 957 patients with IgA nephropathy from the National Clinical Research Center of Kidney Diseases, Nanjing, China, with biopsy-proven kidney disease, stage 1-4 CKD and a follow-up of at least 1 year were recruited. We evaluated the relationship between the baseline phosphorus category and the disease progression in the 2 cohorts.
Results: Multivariate Cox regression analyses indicated that the risk of the endpoint event was 1.68-fold higher (95% confidence interval (CI): 0.95-2.91) in IgA nephropathy patients and 2.88-fold higher (95% CI: 1.12-5.04) in diabetic nephropathy patients with the highest quartile of serum phosphorus compared with the risk of those with the lowest quartile.
Conclusions: The association of serum phosphorus with the progression of CKD may vary in specific CKD patient subgroups. Serum phosphorus is independently associated with the progression of kidney disease in patients with diabetic nephropathy.
Keywords: IgA nephropathy; chronic kidney disease; diabetic nephropathy; phosphorus; risk factors.