How do you decide when to stop immunosuppression in a patient with granulomatosis with polyangiitis who is on dialysis, has not yet recovered renal function, but has shown improvement in ANCA levels?

In a patient with pauci-immune necrotizing GN from GPA on HD, I usually wait for 3 months and up to 6 months if the biopsy is fresh with minimal chronicity before declaring ESRD and stopping IS. If they have extrarenal disease (ENT, lungs), they would need IS for extrarenal disease.

This is a clinical decision based on many factors, such as rapidity of kidney failure, kidney biopsy findings (extent of acute vs. chronic changes), and clinical condition of the patient (in particular the urine output and any sign of renal recovery).