Metabolic acidosis in the initial 6 months after renal transplantation: A prospective study

BACKGROUND There is limited information about the incidence of metabolic acidosis (MA) after renal transplantation. This single centre prospective study aimed to delineate the incidence and risk factors of MA in the first 6 months after renal transplantation (RTX). DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS Patients who underwent RTX between November 2018 and July 2020 were monitored with weekly measurement of serum bicarbonate level for 6 months and those who were diagnosed with MA were evaluated further to characterize the type of MA. RESULTS One hundred and twenty-five patients were included in the study, 89 (71.2%) of whom developed MA. Seventy-two patients developed MA in the first month, 11 during the 2-3 months and 6 between 4 and 6 months after transplantation. Of the 89 patients, 55(61.8%) had type 1 renal tubular acidosis (T1RTA), 27 (30.3%) had type 2 RTA (T2RTA) and 7 (7.9%) type 4 RTA (T4RTA). Two patient who had T1RTA, subsequently developed high anion gap MA following severe graft rejection. On stepwise multivariate regression analysis, serum creatinine at time of diagnosis of MA [OR (95% CI): 12.02 (1.79 to 80.59), p = .01] and high tacrolimus C0 levels [OR (95% CI): 2.43 (1.0 to 5.90), p = .049], were independent risk factors for MA. CONCLUSION There is a high incidence of MA in the initial 6 months post-transplant with serum creatinine and high tacrolimus C0 levels being independent risk factors.