Relative hypophosphatemia early after transplantation is a predictor of good kidney graft function

Phosphate level is a potent independent risk factor for cardiovascular disease and mortality in patients with chronic kidney disease. The association between hypophosphatemia and kidney function in kidney transplant patients is uncertain.

In total, 90 kidney transplant recipients were divided into two groups: one group of patients with hypophosphatemia and the other group without hypophosphatemia. The recipients with hypophosphatemia were identified as having less than or equal to the lowest quartile of serum phosphate levels at 1-, 3-, and 12-month post-transplant. The cumulative kidney survival rates were calculated for each group using the Kaplan-Meier method, and the adjusted hazard ratio (HR) was calculated using the Cox regression model.

The mean age of patients was 47 years and the median follow-up period was 58 months. During the follow-up period, the following results were demonstrated in 90 transplant patients: graft loss (n = 6), mortality (n = 3). According to the Kaplan-Meier analysis results, the patients with hypophosphatemia demonstrated a significantly lower risk of 30% decline in eGFR compared to those without hypophosphatemia at 1- and 3-month post-transplant, but not at 12-month post-transplant. After adjusting for confounding factors, hypophosphatemia at 1- and 3-month post-transplant was an independent predictor of good kidney survival (HR 0.31, 95% CI 0.10-0.82 and HR 0.31, 95% CI 0.07-0.92, respectively).

Our findings suggest that hypophosphatemia during the first 3 months after kidney transplantation was associated with better kidney survival.