Age-related differences in clinical presentation, histopathology, and outcomes in minimal change disease: a TSN-GOLD national registry analysis

Objective: Minimal change disease (MCD) is one of the most common causes of nephrotic syndrome in adults. This study aimed to evaluate age-related differences in clinical presentation, histopathological features, treatment response, and disease outcomes among patients with biopsy-proven MCD in Türkiye. Methods: A total of 379 patients with biopsy-confirmed MCD, recorded in the Turkish Society of Nephrology Glomerular Diseases national registry between 2005 and 2024, were included. Patients were stratified into three age groups: <40 years, 40–64 years, and ≥ 65 years. Demographic, clinical, laboratory, and histopathological variables at diagnosis, as well as treatment modalities and disease outcomes (remission, relapse, immunosuppressive adverse events, decline in renal function, and mortality), were analysed. Results: Of the patients, 62.5% were aged < 40 years, 31.7% were 40–64 years, and 5.8% were ≥ 65 years. The prevalence of hypertension and type 2 diabetes increased with age (p < 0.001). Older patients had lower baseline eGFR (124.6 ± 32.4, 96.7 ± 38.6, and 66.8 ± 27.0 mL/min/1.73 m²; p < 0.001) and a higher prevalence of chronic histological lesions, including interstitial inflammation (15.9%, 41.7%, and 72.7%; p < 0.001), interstitial fibrosis (12.3%, 34.5%, and 40.9%; p < 0.001), vascular changes (9.3%, 28.4%, and 54.5%; p < 0.001), and tubular atrophy (11.0%, 33.9%, and 50.0%; p < 0.001). The use of immunosuppressive therapy was high across all age groups (< 40 years: 84.8%; 40–64 years: 78.8%; ≥65 years: 88.2%; p = 0.414). Complete remission rates were 85.1%, 77.6%, and 100%, respectively (p = 0.126). Relapse was most frequent among younger patients (43.2%) and least common in the elderly (15.4%), whereas adverse events occurred most often in middle-aged patients (44.8%, p = 0.034). Renal function decline—defined as a doubling of serum creatinine or the initiation of kidney replacement therapy—was identified in 2.1%, 7.5%, and 4.8% of patients in groups A, B, and C, respectively (p = 0.04). Mortality increased markedly with age (0.4%, 0.8%, and 9.1%, respectively; p = 0.001). Conclusion: This national registry analysis shows that MCD presentation, histology, and outcomes are strongly age dependent: older patients have more chronic histopathological damage and worse long-term renal outcomes, whereas younger patients have more frequent relapses. These findings support age-tailored diagnostic and therapeutic strategies in MCD and highlight the importance of large-scale registry data such as TSN-GOLD for guiding clinical practice.