MO240: The Evolution and Epidemiology of Membranous Nephropathy at a Single Centre Over Two Decades
Authors: Storrar Josh , Gill-Taylor Tarra , Chinnadurai Rajkumar , Sinha Smeeta , Kalra Philip A 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Membranous nephropathy (MN) commonly presents with nephrotic syndrome and carries significant risk of progression to end-stage kidney disease (ESKD) (33% without treatment, 10%–20% with). Patients may spontaneously remit (up to 40%), but are also at risk of relapse. A total of 80% of cases are primary (kidney-specific) and the majority of these are associated with antibodies to the M-type phospholipase A2 receptor (anti-PLA2R) or thrombospondin type 1 domain containing 7A antibodies (THS7DA). Treatment ranges from supportive care with renin–angiotensin system (RAS) blockade through to immunosuppression. Here we assessed the epidemiology of MN over 20 years at our centre (Salford Royal Hospital, UK) with particular reference to treatment administered and key clinical outcomes.

METHOD
A total of 238 patients with kidney biopsy-proven MN were identified from the local database between January 2000 and December 2020. Twenty-one were excluded (see Fig. 1) resulting in a total of 217 patients in whom demographic data, co-morbidities, remission and relapse rates, baseline laboratory values, treatment given, and outcomes were collected. Analyses compared effects of (i) immunosuppressed versus non-immunosuppressed, (ii) effect of modified Ponticelli versus other forms of immunosuppression and (iii) rates of remission. Univariate and multivariate cox regression determined factors that were associated with increased risk of renal replacement therapy (RRT) or death.

RESULTS
A total of 63.6% of the cohort were male, 88% Caucasian, 10.1% diabetic, 50.2% hypertensive and 15.2% had coexisting cardiovascular disease (Table 1). A total of 82.0% had primary MN. Median baseline eGFR was 72.7 mL/min/1.73 m2 and median baseline uPCR was 664 g/mol. A total of 157 patients (72.4%) went into remission (either spontaneous—75 (47.8%) or with treatment—85 (52.2%)), and of these 41.4% subsequently relapsed. A total of 89.4% received RAS blockade and 48.8% received immunosuppression. The median follow-up period was 56 months; 9.7% progressed to ESKD and 32.3% died.
Patients who received immunosuppression had significantly more proteinuria than those who did not (765 g/mol versus 514 g/mol, P ≤ 0.001), were more likely to relapse (53.7% versus 28.0%, p ≤0.001) and were more likely to require RRT (15.1% versus 4.9%, P = .028). Those who received modified Ponticelli were less likely to relapse than those who received other forms of immunosuppression (34% versus 46%, P = .019), less likely to require RRT (3% versus 22%, P = .018) and less likely to die (11% versus 38%).
Multivariate cox regression showed that pre-existing cardiovascular disease was a risk factor for death (HR 2.47, P &lt; .001) and higher baseline eGFR and use of RAS blockade was associated with reduced risk of death (HR 0.98, P &lt; .001 and HR 0.34, P = .012, respectively).

CONCLUSION
Despite advances in knowledge of underlying pathogenesis and increased treatment options, MN continues to pose a significant risk of progression to ESKD and death. This real-world study suggests that immunosuppression with modified Ponticelli is associated with lower rates of progressive CKD compared with MMF and calcineurin-inhibitor based therapy. Whilst many patients respond to treatment and can achieve remission, a significant proportion of these subsequently relapse. Identifying these patients early with judicial use of appropriate immunosuppression is key.