TOPIC DISCUSSION: IgA nephropathy and FSGS

What is the significance of findings of FSGS in biopsies that are predominately IgA nephropathy?

Two studies have looked into this matter in 2009 and 2011.

The NDT study in 2009 looked at 75 patients ( split into IGA with FSGS, IGA without FSGS).  In the multivariate model, the FSGS+ group showed a worse GFR decline.  It is no surprise that when there is sclerotic lesions, the prognosis is going to be worse. The question arises if this is part of IGA progression or it is two processes happening independently? Would steroids be indicated in such settings?

The KI study from 2011 looked at over 100 patients and used the Oxford classification for IgA and Columbia classification for FSGS to evaluate the two seen in the same biopsy.  Collapsing FSGS with IgA had worse outcomes.  Overall, worse outcomes were noted with any form of FSGS was present when compared to IgA alone.  In addition, when FSGS was present with any other glomerular findings( mesangial hypercellularity, necrosis, deposits), outcomes were worse compared to “pure” FSGS.
Staining studies they performed showed that the changes related to the podocytopathy were present even with mild IgA disease suggesting that the two processes might be independent and not just an end pathway for any glomerular disease. 

IgA can present with preserved renal function and MCD like podocytopathy.  Presenting with FSGS is more challenging and treatment may be difficult to decide upon.  If there is good preservation of IFTA on biopsy and if there is >1gm of proteinuria, perhaps it’s worth treating with steroids or at least a trial of steroids.