COMPLICATIONS - METABOLIC

E. Baskin¹, U.S. Bayrakci¹, K. Gulleroglu¹, E. Melek¹, S. Sevmis², H. Karakayali², M. Haberal^2
1Pediatric Nephrology, Baskent University, Ankara/TURKEY, ²General Surgery And Transplantation, Baskent University, Ankara/TURKEY

Body: Long term renal transplant recipients with adequate graft function develop post-transplant renal tubular acidosis (RTA). However, neither the prevalence nor the associated risk factors of late post-transplant RTA are known. Although calcineurin inhibitors (CNI), suboptimal allograft function, donor age and acute rejection have been associated with RTA, no detailed study has been conducted to investigate the prevalence and clinical implications of RTA in long-term kidney recipients. METHODS: In this cross-sectional study, we enrolled 44 patients (M/F:20/24) for the study. The mean age of patients was 15.8±5 years and the median duration of follow-up was 17.5 months. Patients with glomerular filtration rate (GFR) <30 ml/min/1.73 m², unstable allograft function, diarrhea, and respiratory disease were excluded. RTA was diagnosed on the basis of low arterial bicarbonate (<22 mEq/l) and pH (<7.37) together with normal serum anion gap and positive urine anion gap. RESULTS: Nineteen patients (43.2%) were found to have RTA on the basis of plasma bicarbonate, arterial pH, and urine and serum anion gap measurements. GFR was found to be lower in patients with RTA (74±22.3 in RTA and 102.6±34.4 ml/min/1.73 m² in non-RTA, P = 0.003). Uric acid and creatinine levels were found to be higher in the RTA group (uric acid: 5.8±1.5 mg/dl vs. 4.5±1.6 mg/dl, p=0.02, creatinine: 1.1±0.38 mg/dl vs. 0.78±0.33 mg/dl, p=0.001), while no difference was noticed in body mass index, CRP or serum albumin. Parathyroid hormone levels were also found to be significantly higher in patients with RTA (93.3±54.3 ng/dl vs. 58.5±23.8 ng/dl, p=0.01). Analysis of the prevalence of osteoporosis and osteopenia in patients with RTA and without RTA, respectively, revealed no difference in frequency of osteoporosis (42% vs. 52%) or osteopenia (31.6% vs. 36%). We also did not find any relation between renal tubular acidosis and immunosuppressive regimen or trough levels of CNI. CONCLUSION: Although long-term kidney recipients have a relatively high prevalence of RTA, it is usually mild and subclinical. Further studies are needed to clarify long-term effects of RTA in kidney recipients.

Disclosure: All authors have declared no conflicts of interest.