Sex Differences in Baseline Characteristics and Long-Term Outcomes of Primary Glomerular Diseases: Insights from the TSN-GOLD Registry

Abstract

Background: Primary glomerular diseases (PGDs) are a leading cause of end-stage kidney disease (ESKD). While sex differences in chronic kidney disease progression have been reported, their role in PGDs remains unclear. Methods: We analyzed 2081 patients with biopsy-proven PGDs from the Turkish Society of Nephrology Glomerular Diseases Working Group (TSN-GOLD) registry. Baseline demographic, clinical, biochemical, and histopathological characteristics were compared between women and men. Outcomes were assessed as a composite of ESKD or death. Logistic and Cox regression models were applied to identify independent risk factors. Kaplan-Meier analyses evaluated survival differences. Results: At baseline, women and men had similar rates of hypertension (36.8% vs. 34.7%, p = 0.322). Women more frequently presented with leukocyturia (31.7% vs. 17.2%, p < 0.001) and hematuria (57.8% vs. 52.3%, p = 0.016), whereas men had higher proteinuria (5011 +/- 4925 vs. 4388 +/- 4529 mg/day, p = 0.003) and were more likely to be active smokers (20.7% vs. 7.4%, p < 0.001). Serum albumin (3.3 +/- 0.8 vs. 3.2 +/- 0.9 g/dL) and eGFR (79.7 +/- 44.3 vs. 78.7 +/- 45.5 mL/min/1.73 m(2)) were comparable between sexes (both NS). During a median follow-up of 24 months (IQR 7-60), 431 patients (20.7%) reached the composite outcome of ESKD or death (137 deaths [6.6%], 294 ESKD [14.1%]). In the multivariable Cox regression model, lower baseline eGFR (HR 0.98, 95% CI 0.98-0.98, p < 0.001), lower serum albumin (HR 0.65, 95% CI 0.55-0.77, p < 0.001), higher proteinuria (HR 1.03, 95% CI 1.00-1.05, p = 0.043), and biopsy diagnosis of RPGN (HR 3.78, 95% CI 1.37-10.45, p = 0.010) were independent predictors of poor prognosis. Sex was not an independent predictor of outcome (p = 0.48). Kaplan-Meier analysis demonstrated no significant survival difference between women and men (log-rank p = 0.052). Conclusions: In this nationwide PGD cohort, women and men differed significantly in baseline biochemical and clinical parameters, yet sex was not independently associated with progression to ESKD or death. Instead, disease severity at baseline and histopathological features were the main drivers of prognosis.