Evaluation of renal function and hypertension status in pediatric patients who underwent bone marrow transplantation in our clinic between 2012-2022

Introduction and Aim: Hematopoietic stem cell transplantation (HSCT) has been successfully used for decades in the treatment of both malignant and non-malignant diseases. This procedure reconstructs the immune system, extending patients' survival and improving their quality of life. The frequency of HSCT applications has been increasing, particularly in pediatric patients. However, long-term effects of transplantation may lead to complications such as acute kidney injury (AKI), hypertension, proteinuria, hemorrhagic cystitis, and chronic kidney disease (CKD), which significantly contribute to morbidity and mortality. Materials and Methods: In this study, we retrospectively evaluated the outcomes of pediatric patients who underwent HSCT at Çukurova University Faculty of Medicine Pediatric Bone Marrow Transplantation Unit between 2012 and 2022. The renal function status before transplantation and one year post-transplant, as well as etiological factors, were analyzed. The presence of proteinuria was assessed using a qualitative dipstick test. Estimated glomerular filtration rate (eGFR) was calculated using the Schwartz formula, and chronic kidney disease staging was determined based on KDIGO 2012 criteria. Results: Among the patients, 64.1% were male and 35.9% were female, with a mean age of 7.6 years. The proportion of patients undergoing transplantation due to malignancy was 36.7%, whereas 63.3% underwent transplantation for non-malignant conditions. Bone marrow was used as the stem cell source in 62.6% of patients, while 37.4% received peripheral stem cells. Myeloablative conditioning regimens were administered in 66.4% of patients, while 33.6% received reduced-intensity conditioning. Acute graft-versus-host disease (GVHD) was observed in 25.2% of patients, while 4.4% developed chronic GVHD. The most frequently affected organs in GVHD were the skin and intestines (27.9%), followed by isolated skin involvement (22%). Cytomegalovirus (CMV) infection was detected in 54.7% of patients, and BK virus infection was found in 43.4%. The incidence of hemorrhagic cystitis was 17.4%. The most frequently used treatment regimen included cidofovir and probenecid (50.8%). Blood culture positivity was found in 29.9% of patients, with Staphylococcus epidermidis being the most common isolate (7.3%). Disease relapse occurred in 13.5% of patients, and 9.9% required a second HSCT. The 5-year and 10-year survival rates were both 57%. No significant difference was observed in survival rates between genders (p=0.760). When comparing survival rates based on disease type, leukemia patients had a survival rate of 42%, whereas patients with solid tumors had a survival rate of 58%, demonstrating a significant association (p=0.009). The type of transplantation and the stem cell source did not significantly affect survival. However, higher HLA compatibility was associated with significantly improved survival rates (p=0.001). The survival rate of patients who developed acute GVHD was 48%, which was significantly lower than those without acute GVHD (p=0.004). Post-transplant hypertension was observed in 19.1% of patients, whereas only 2.8% remained hypertensive one year later. Based on KDIGO staging before transplantation, 92.7% of patients were classified as G1, 5.9% as G2, 0.9% as G3a, 0.3% as G3b, and 0.3% as G4, with no patients in G5. One year post-transplant, 84.6% were classified as G1, 9.8% as G2, 1.4% as G3a, 3.3% as G3b, and 0.9% as G4, while no patients reached G5. Conclusion: Our findings indicate that multiple factors contribute to renal dysfunction following HSCT. Patients with renal impairment exhibited significantly lower survival rates. Close monitoring and early intervention for hypertension and infections, both pre- and post-transplant, are crucial for preserving renal function and improving long-term outcomes. Keywords: Hematopoietic Stem Cell Transplantation, Hypertension, Renal Dysfunction, Pediatric