Hypophosphatemia after hemodialysis and its association with some clinical complications in patients with chronic kidney disease

Beyond the adverse effects of hyperphosphatemia in patients with chronic kidney disease (CKD(, hypophosphatemia has also been proposed as a common challenge after dialysis. Therefore, the present study aimed to evaluate the serum phosphate level immediately after hemodialysis (HD) and its association with some clinical complications in CKD patients.

The present cross-sectional study was conducted on 54 eligible CKD patients undergoing regular hemodialysis. Blood samples were taken, prior to the start and immediately after the end of hemodialysis to determine the serum levels of urea, creatinine, sodium, potassium, phosphorus, PTH, blood sugar and albumin. Moreover, the clinical complications of patients including muscle cramps, nausea, vomiting, headache, confusion, weakness and inability to speak are assessed by a questionnaire, before and after HD.

As we expected, the mean of serum creatinine, urea and phosphate levels significantly decreased after dialysis. Post-dialysis hypophosphatemia was graded as mild (3.5 > P ≥ 2.5 mg/dl), moderate (2.5 > P ≥ 1 mg/dl), and severe (<1 mg/dl) based on serum phosphate levels. The frequency of mild and moderate hypophosphatemia was 39.2% and 45.1 %, respectively. None of the participants had severe hypophosphatemia and 13.7% had normal phosphate levels. There was a significant correlation between post-dialysis hypophosphatemia and incidence of nausea and confusion after adjusting for confounding factors.

To our knowledge, this is the first time that the possible association of some of the post-dialysis clinical complications with hypophosphatemia was investigated. Future large-scale studies are required to confirm the association of post-dialysis hypophosphatemia with clinical complications.