Background: While the number of kidney transplants for end-stage renal disease (ESRD) is increasing, studies examining the long-term demographic analyses based on pathological diagnosis of transplant kidney remain limited. Methods: We conducted a retrospective analysis of 4,188 transplant recipients who underwent either biopsy or nephrectomy from 1991 to 2023 at Seoul St. Mary's Hospital. Results: Among 7,229 pathologically confirmed cases, rejection was the most prevalent (37.8%), followed by tubulointerstitial (25.4%), glomerular, drug toxicity, and vascular diseases. In 7,053 transplant biopsies, rejection was predominant across all age groups, with T-cell mediated (TCM) category being the most common (60.1%), followed by antibody-mediated and mixed. Drug toxicity increased with age (p = .047), while glomerular and tubulointerstitial diseases were highest in recipients under 20 (p < .001). Among glomerular diseases, IgA-related glomerulonephritis (45.2%) was the most common. In 176 transplant nephrectomies, the most common diagnosis was rejection (33.5%), followed by renal infarction (19.9%), tubulointerstitial, vascular, glomerular disease, and drug toxicity. "Others" included infarction, ESRD, and lymphangiectasia, which increased with age (p = .011). In nephrectomy cases, rejection decreased over time, with chronic TCM rejection (40.7%) being the most frequent. Conclusions: This study provides valuable insights into transplant kidney disease in South Korea. The number of transplant biopsies has increased over the past 33 years, while the number of nephrectomies has remained unchanged. Rejection was the most common finding in all age groups in biopsies, but decreased with age in nephrectomies, with TCM being the most common and observed more often in younger recipients.
Noh et al. (2026) studied this question.