Membranous nephropathy: a retrospective observational study of membranous nephropathy in north east and central London

BACKGROUND: Membranous nephropathy (MN) is the leading cause of nephrotic syndrome in adults. MN is a clinically heterogeneous disease and it is difficult to accurately predict outcomes (including end stage renal failure) at presentation and whom to treat with potentially toxic therapies. We aimed to identify factors predicting outcome in MN in our cohort from two large tertiary London units by undertaking a retrospective data analysis of 148 biopsy-proven MN patients from North East and Central London between 1995 and 2015. METHODS: Review of clinical and biochemistry databases. RESULTS: Surprisingly, patients that reached end stage renal failure (ESRF) had a less severe nephrosis compared to those that did not develop ESRF; serum albumin 33 g/L (3.3 g/dL) versus 24 g/L (2.4 g/dL), p = 0.002 and urinary protein creatinine ratio (uPCR) 550 mg/mmol (5500 mg/g) versus 902 mg/mmol (9020 mg/g), p = 0.0124. The correlation with ESRF was strongest with the presenting creatinine; 215 μmol/L (2.43 mg/dL) compared to 81 μmol/L (0.92 mg/dL), p < 0.0001. Patients presenting with creatinine of >120 μmol/L (1.36 mg/dL; corresponding to an eGFR of ≤60 ml/min in non-Black males) had an increased rate of ESRF and a faster decline. Other traditional risk factors for progression were not significantly associated with ESRF. Black patients presented with higher serum creatinine but no statistically significant difference in the estimated glomerular filtration rate, a higher rate of progression to ESRF and had a poorer response to treatment. CONCLUSIONS: This ethnically diverse cohort does not demonstrate the traditional risk profile associated with development of ESRF. Thus, careful consideration of therapeutic options is crucial, as current risk modelling cannot accurately predict the risk of ESRF. Further studies are required to elucidate the role of antibodies and risk genes.