Long‐term follow‐up in 49 patients with microscopic polyarteritis

We treated 49 patients with microscopic polyarteritis (31M:18F) aged 14-76 years (mean 51) between 1974 and 1988. All were followed for at least 1 year with mean followup 8.4 years. Presenting features, treatment and outcoume were compared with a group of 60 patients with Wegener’s granulomatosis which we have reported previously (Nephrol Dial Transplant 1989:4, 832-3). All patients has a focal necrotising glomerulonephritis. Dialysis was reguired on admission in 14 patients. Mean serum creatinine in the remaining 35 patients was 456 umol/l. Evidence of pulmonary haemorrhage was seen in 16 patients. Other clinical features included muscle and joint pains, vasculitic rashes, gastrointestinal involvement and neurological and eye disease. ANCA were detected at presentation in all new patients since 1985, (following the introduction of the assay) and assays performed retrospectively or during follow-up revealed ANCA in a further 11/16 patients. Initial treatment included prednisolone (in 47/49), cyclophosphamide (in 44/49), azathioprine (in 20/49) and plasma exchange (in 31/49). At 1 year 33/49 were alive, (30 with independent renal function); at 5 years 21/39 were alive (16 with independent renal function); and at 10 years 11/21 alive (9 with independent renal function). By the end of the study 20 patients had died. 15 deaths occurred within the fEst year, of which 6 were due to lung haemorrhage. Of 14 patients initially requiring dialysis, 6 had recovered independent renal function by 2 months; 2 were on regular dialysis; 6 had died (3 due to vasculitits). Of those who recovered, 4 maintained independent renal function at 21, 28, 79 and 171 months; a fifth died of an unrelated condition after 12 years. Episodes of relapse occurred in 17 patients and 2 patients died in relapse at 8 and 21 months after presentation. These results are similar to those seen in long-term followup of patients with Wegener’s granulomatosis and demonstrate the possibility of long-term survival following immunosuppressive therapy.