Hyperphosphatemia and Anemia Risk Factors in Diabetic Nephropathy Patients
LAS VEGAS—Albumunuria, proteinuria, lower estimated glomerular filtration rate (eGFR) in patients with diabetic nephropathy are significantly associated with hyperphosphatemia and anemia, according to researchers.
Gautham Viswanathan, MD, of Tufts Medical Center in Boston, and colleagues noted that it is unknown whether albuminuria is associated with concurrent complications of chronic kidney disease (CKD) or if these associations differ for proteinuria compared with albuminuria.
The investigators studied 1,576 participants in the Irbesartan in Diabetic Nephropathy Trial to evaluate the association between 24-hour aluminuria and proteinuria with hyperphosphatemia (phosphate level greater than 4.6 mg/dL) and anemia (hemoglobin level below 12 g/dL in women and below 13.5 g/dL in men). Albuminuria and proteinuria were categorized by tertiles.
Compared with patients with 24-hour urinary albumin excretion less than 1.3 grams, those with 24-hour excretion of 1.31-2.82 and more than 2.82 grams had an approximately 1.5 times and 2.2 times increased risk of hyperphosphatemia and a 1.3 times and 1.5 times increased risk of anemia, after adjusting for age, gender, race, and eGFR as a continuous variable, the investigators reported at the National Kidney Foundation's Spring Clinical Meetings.
Compared with patients whose 24-hour urinary protein excretion was less than 2.06 grams, subjects whose protein excretion was 2.06-4.28 and greater than 4.28 grams had an approximately 1.3 times and 2.1 times increased risk of hyperphosphatemia and 1.3 times and 1.6 times increased risk of anemia.
In addition, compared with patients who had an eGFR of 60-89 mL/min/1.73 m2, those with an eGFR below 29 had a 2.3 times increased risk of hyperphosphatemia. The risk was not increased significantly for subjects with an eGFR of 30-59. Participants with an eGFR of 30-59 and less than 29 had a 2.2 and 5.5 times increased risk of anemia.
The authors concluded that anemia and hyperphosphatemia are more strongly associated with eGFR than albuminuria.
The differences between eGFR and albuminuria in the magnitude of the association with complications should be taken into consideration when including albuminuria level in the classification of CKD, the authors stated.