Long-term outcomes of adults with FSGS in the German Chronic Kidney Disease cohort

Background Focal segmental glomerulosclerosis (FSGS) can lead to kidney failure in adults. This study examines the progression of FSGS in the German Chronic Kidney Disease (GCKD) cohort. Methods The GCKD study (N = 5217), a prospective cohort, included 159 patients with biopsy-confirmed FSGS recruited from 2010 to 2012. Baseline was defined as the first study visit. Adjudicated endpoints included a composite kidney endpoint (CKE), including an estimated glomerular filtration rate (eGFR) decrease >40%, eGFR <15 ml/min/1.73 m(2) or initiation of kidney replacement therapy and combined major adverse cardiovascular events (MACE), including non-fatal myocardial infarction or stroke and all-cause mortality. Associations between baseline demographics, laboratory data, comorbidity and CKE and MACE were analysed using the Cox proportional hazards regression model. Results The mean age at baseline was 52.1 +/- 13.6 years, with a disease duration of 4.72 years (quartile 1: 1; quartile 3: 6) before joining the study. The median urinary albumin:creatinine ratio (UACR) at baseline was 0.7 g/g (IQR 0.1;1.8), while mean eGFR was 55.8 +/- 23 ml/min/1.73 m(2). Based on clinical and pathological features, 69 (43.4%) patients were categorized as primary FSGS, 55 (34.6%) as secondary FSGS and 35 (22%) as indeterminate. Over a follow-up of 6.5 years, 44 patients reached the composite kidney endpoint and 16 individuals had at least one MACE. UACR >= 0.7 g/g was strongly associated with both the composite kidney endpoint {hazard ratio [HR] 5.27 [95% confidence interval (CI) 2.4-11.5]} and MACE [HR 3.37 (95% CI 1.05-10.82)] compared with <0.7 g/g, whereas a higher eGFR at baseline (per 10 ml/min) was protective for both endpoints [HR 0.8 (95% CI 0.68-0.95) and HR 0.63 (95% CI 0.46-0.88), respectively]. Patients with secondary FSGS experienced a greater rate of eGFR decline than patients with primary FSGS. Conclusions Lower eGFR and higher albuminuria are key risk factors for kidney disease progression and cardiovascular events in patients with FSGS.