#3184 CHRONIC KIDNEY DISEASE IN NON-RENAL SOLID ORGAN TRANSPLANTATION: WHAT IS THE ROLE OF THE NEPHROLOGIST?
Authors: Boyano Iris Viejo , Romero Luis Carlos López , Peris-Fernandez Maria , D'marco Luis , Almerich Enrique Garrigos , Ramos Carmela , Peris Ana , Jaras Julio Hernandez 
Published: June 2023

Abstract

Background and Aims
Chronic kidney disease (CKD) is a frequent complication of non-kidney solid organ transplant (NKSOT) and is related to increased morbidity and mortality. Identifying predisposing factors is crucial for an early approach and correct referral to Nephrology, a specialty with an important role in managing these patients.

Method
This is a single-center retrospective observational study of a cohort of CKD patients under follow-up in the department of nephrology during the period between January 2010 to December 2020. A total of 212 patients were analyzed. Patients transplanted before 2010 (101 patients), with combined transplantation with renal transplantation (9 patients), and those with no follow-up in external consultations (28 patients) were removed from the sample. A final population sample was obtained with 74 patients. Statistical analysis was performed between all the risk above factors (Figure 1) and the four dependent variables: advanced chronic kidney disease (ACKD), increased serum creatinine ≥50%, renal replacement therapy (RRT), and death in three different periods: pre-transplant period, peri-transplant period and post-transplant period.

Results
74 patients were analyzed (7 heart transplant recipients, 34 liver transplant recipients, and 33 lung transplant recipients).
• 45 patients presented an increase in Creatinine ≥50%. Receiving a lung transplant confers more risk versus a liver (HR 0.048 [95% CI] 0.012 to 0.192) or heart (HR 0.075 [95% CI] 0.01 to 0.5) transplant. It was significantly associated with pre-transplant obesity (p 0.003), peri-transplant mechanical ventilation (p &lt; 0.001), peri-transplant (p 0.009) and post-transplant (p. 005) anticalcineurin overdose, peri-transplant (p. 0.046) and post-transplant nephrotoxics (0.03) and the number of hospital admissions (p. 0.002). Not having follow-up by Nephrology in the pre-transplant (p 0.027), peri-transplant (p. 0.045), and the longest time until external consultations (HR 1,032 [95% CI] 1,011 to 1,054) conferred more risk.
• 24 patients developed ACKD. Receiving a lung transplant confers more risk versus a liver (HR 0.14 [95% CI] 0.045 to 0.463) or heart (HR 0.13 [95% CI] 0.015 to 1.28) transplant. Per-transplant mechanical ventilation (p. 0.03), peri-transplant (p. 0.024) and post-transplant (p. 0.038) anticalcineurin overdose, peri-transplant (p. 0.045) and post-transplant nephrotoxic antimicrobials (p. 0.04) and the number of hospital admissions (p 0.015) were significantly associated. The time to nephrology consultations after the transplant (p 0.035) conferred more risk. Mean ACKD-free survival was 93.29 months (95% CI 79.04-107.5), 121.5 months in heart transplantation recipients (95% CI of 86.70-155.297), 104 months in liver transplantation recipients (95% CI of 86.67-122.134) and 66.86 months in lung transplantation recipients (CI at 95% of 55.93 – 80.79) (Figure 2).
• 8 patients required RRT. It was significantly associated with the active smoking habit in the pre-transplant period (p 0.02) and the overdose of calcineurin inhibitors in the peri-transplant period (p 0.045).
• 21 patients died. It was significantly associated with the active smoking habit in the pre-transplant (p. 0.03) and the number of hospital admissions in the post-transplant (p 0.006).

Conclusion
Early follow-up by Nephrology is associated with a decrease in the deterioration of renal function and the development of advanced chronic kidney disease, by being able to act on the risk factors for each transplant recipient, such as an overdose of calcineurin inhibitors and nephrotoxicity, and allowing the identification of patients at higher risk, such as those requiring mechanical ventilation during peri-transplantation, patients with the highest number of hospital admissions, and lung transplant patients.