Renal tubular acidosis in renal transplantation recipients

We aimed to investigate the prevalence, type, and possible risk factors of renal tubular acidosis (RTA) in Turkish patients with renal transplantation.

The study included 66 adult renal transplantation recipients. We recorded the parameters of venous blood gas analysis including serum pH value, serum bicarbonate (HCO(3)) concentration, presence of metabolic acidosis, which was defined as low HCO(3) (<22 mEq/L), and serum pH value (<7.35) together, and base excess and urine pH at the last follow-up. Creatinine clearance was determined from 24-hour collected urine samples. RTA was defined to be metabolic acidosis with normal serum anion gap and positive urine anion gap.

Mean age of 66 patients was 37.0 +/- 10.4 years; 48 of 66 patients were male. RTA was found in 14 (21.2%) patients. Considering for differential diagnosis of RTA, 4 patients had type 2 RTA and 10 had type 1 RTA. On the contrary, type 4 RTA was observed in no patients. Creatinine clearance was meaningfully lower in acidosis group than in those of the nonacidosis group (55.16 +/- 23.27 vs. 71.06 +/- 28.14 mL/min; p = 0.028). HCO(3) was correlated with hemoglobin level (r = 0.423, p = 0.001) and creatinine clearance (r = 0.262, p = 0.034). It was inversely correlated with cyclosporine A (CsA) level (r = -0.499, p = 0.035).

RTA is a common complication after kidney transplantation. It is related with low creatinine clearance, low hemoglobin level, and high CsA level. Particularly, the value of creatinine clearance is lower and the possibility of RTA is higher.