Kidney Injury in Adults After Hematopoietic Stem Cell Transplantation: Acute Kidney Injury, Transplant-Related Complications, and Long-Term Outcomes

Kidney complications are common after hematopoietic stem cell transplantation (HSCT) and contribute substantially to short- and long-term morbidity and mortality. Acute kidney injury (AKI) affects a large proportion of recipients, particularly after allogeneic transplantation, and reflects the combined effects of baseline patient vulnerability, conditioning intensity, calcineurin inhibitor exposure, infection, hemodynamic disturbances, and transplant-specific complications. This review summarizes the epidemiology, risk factors, and major causes of kidney injury after HSCT, with emphasis on a time-based diagnostic approach. Important etiologies include sepsis, marrow infusion syndrome, sinusoidal obstruction syndrome, graft-versus-host disease-associated kidney injury, transplant-associated thrombotic microangiopathy, and glomerular disease. We also discuss emerging therapeutic approaches, including complement-directed therapy for transplant-associated thrombotic microangiopathy and defibrotide for sinusoidal obstruction syndrome. Beyond the acute transplant period, AKI is increasingly recognized as a major determinant of subsequent chronic kidney disease, cardiovascular risk, and impaired long-term survival. Structured surveillance of kidney function, blood pressure, and proteinuria, together with early recognition of transplant-specific syndromes and closer nephrology follow-up in high-risk patients, is therefore essential. Multidisciplinary collaboration between transplant hematology and nephrology is central to improving kidney and overall outcomes across the HSCT continuum.