What factors do you consider when deciding to treat IgA nephropathy with immunosuppression in a patient with cirrhosis, given the possibility that IgA nephropathy could be secondary to cirrhosis?

Proteinuria is the most important factor here. If there is significant proteinuria (>1 g/d) and no other clear reason for it, I would treat the IgA nephropathy with immunosuppression. Secondary IgA due to cirrhosis is usually not associated with significant proteinuria.

This would constitute a secondary form of IgA Nephropathy and immunosuppression is not generally not given. Treatment of secondary forms of IgA Nephropathy mandates treatment of the underlying etiology.

The degree of proteinuria

Proteinuria and current GFR