A single-institution demographic study of pathologically proven kidney disease in South Korea over the last 33 years.

Background: To date, epidemiological studies on the entire spectrum of kidney disease based on pathology have been rarely reported.

Methods: A retrospective study was conducted on patients diagnosed with kidney disease at Seoul St. Mary's Hospital between 1991 and 2023.

Results: Among 7,803 patients with native kidney disease, glomerular disease (70.3%) was the most common, followed by tubulointerstitial (15.1%) and vascular disease (8.8%). In kidney biopsy, glomerular disease (77.8%) showed the highest frequency, particularly in those under 20s (95.6%) (p = .013). Primary glomerulonephritis (GN) (72.8%) was the predominant glomerular disease, with IgA nephropathy (IgAN) (47.3%) being the most common one. Tubulointerstitial and vascular diseases increased with age, showing the highest prevalence in those over 60 years (p = .008 and p = .032, respectively). Glomerular disease was diagnosed at a younger age (39.7 ± 16.7 years) than tubulointerstitial (49.1 ± 16.2) and vascular (48.1 ± 15.3) diseases (p < .001). When glomerular diseases were classified morphologically, proliferative GN (57.9%) was the most common, followed by non-proliferative (39.6%) and sclerosing (1.6%). When classified by etiology, primary GN accounted for the most (72.8%), followed by secondary (19.3%) and hereditary GN (5.7%). In nephrectomy, tubulointerstitial disease (64.6%) was the most common. Those with a tubulointerstitial disease had a higher mean age than those with a glomerular disease (p < .001). In cases where nephrectomy was performed for glomerular diseases, IgAN (34.1%) was the most common diagnosis.

Conclusions: Kidney disease has been increasing in South Korea for 33 years. Glomerular disease was the most common across all age groups, tubulointerstitial and vascular diseases increased over 60 years.