Microscopic polyarteritis has a poor prognosis in Chinese.

OBJECTIVE

To analyze retrospectively the clinical course and outcome of 10 consecutive Chinese patients with microscopic polyarteritis (MPA) admitted to our hospital over a period of 3 years.

METHODS

Ten patients with MPA who presented 1990-93 were studied. Their serum antineutrophil cytoplasmic autoantibody levels were assayed.

RESULTS

The male to female ratio was 1:1 and the mean age was 61 years. Eight patients (80%) had renal impairment on presentation and 5 of them (50%) were dialysis dependent. Seven patients (70%), during their clinical course, had pulmonary hemorrhage. Six patients (60%) had hypoxic lung disease requiring ventilatory support. All 10 patients were pANCA positive; 8 patients were tested for antimyeloperoxidase antibody and were all positive. Seven patients were treated with immunosuppressants consisting of steroid and cyclophosphamide with additional plasma exchange. Nine patients died after a mean survival of 9 months (range 1-33); causes of death were respiratory failure (5), infection (2), uremia (one), and stroke (one). The ANCA level reflected the disease activity of the vasculitis.

CONCLUSION

MPA in Chinese patients appeared to be a more severe disease with a poor prognosis. This may be related to the older age group, and the more frequent and severe pulmonary and renal manifestations of MPA in these patients.