In addition, hyperphosphatemia and hyperuricemia—which are other time-dependent factors that change with the natural course of CKD and treatment—emerged as important potential targets for clinical intervention.
For the retrospective study, investigators led by Shunya Uchida, MD, of Teikyo University in Tokyo, calculated the yearly decline in estimated glomerular filtration rate (eGFR) for 770 male and female patients with CKD stages 3 or 4 and correlated eGFR with follow-up laboratory results taken every 1–3 months for an average of 4 years (prior to dialysis initiation). The researchers looked at a host of blood and urinary parameters, such as hemoglobin, albumin, nitrogen, creatinine, hematuria, uric acid, sodium, potassium, phosphate, low-density lipoprotein cholesterol, and C-reactive protein.
According to results published online in Clinical and Experimental Nephrology, risk factors strongly associated with more rapid decline in eGFR included proteinuria, hyperphosphatemia, and anemia, suggesting these factors could be targets for intervention. Older age, lower albumin, and higher hemoglobin appeared to be protective.
The investigators speculated that higher phosphorus levels and subsequent calcium deposits may contribute to arterial sclerosis.
The study also found that men with CKD experience more rapid decline in kidney function than women (average eGFR decline 2.83 vs. 1.66 mL/min/1.73 m2 per year).
Limitations of the study included lack of information about medication usage (other than antihypertensive drugs), genetic factors, and parameters related to CKD mineral bone disease.
Chang, W, et al. Clin Exp Nephrol, June 2015; doi: 10.1007/s10157-015-1132-0.