Classification of clinical subtypes, patient survival, kidney prognosis, and relapse in patients with MPO-ANCA-associated vasculitis: a single-center experience

Myeloperoxidase-type antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis may manifest various organ symptoms. Treatment allows recovery from early, but severe, organ involvement. However, the relationship between the initial organ involvement and the eventual clinical course has not been studied in this disease. Therefore, the current study evaluated 30 patients who were hospitalized and then categorized into ten clinical subtypes based on organ involvement. The relationship of these subtypes to development of clinical features, patient survival, kidney prognosis, and relapse were evaluated over an average observation period of 4.3 years. During this study, the most common clinical features were lung and kidney involvement. Twenty-one patients already manifested clinical features around the time of admission and did not commonly present new symptoms as long as they were receiving the treatment for vasculitis. In contrast, as far as pulmonary involvement type at the initial time was concerned and in those not being treated for vasculitis, 7 of the 12 patients progressed to pulmo-renal involvement and 5 of them went onto renal failure. Progression to renal failure also occurred frequently in patients with pulmo-renal type manifesting at the initial time. Thirteen patients died, including three patients due to vasculitis of systemic type, seven due to infections, and three due to malignancy. Death due to vasculitis occurred in the early phase of treatment and was associated with either pulmonary hemorrhage or gastrointestinal bleeding. Infectious death occurred throughout the entire course of treatment, mostly in patients with pulmo-renal or pulmonary type, and tended to be associated with opportunistic organisms. Death with malignancy was observed after several years of treatment. Regarding renal prognosis, ten patients underwent hemodialysis. At initiation of hemodialysis, nine patients had pulmo-renal type and only one had renal type. A relapse was observed in ten patients, mainly in patients with pulmo-renal or pulmonary type, and it occurred after about 2.7 years, even with treatment. Such relapses manifested in a similar manner to their initial clinical subtypes. These results suggest that pulmo-renal type as well as pulmonary type have a high chance to progress to renal failure or systemic type, and they were fairly commonly associated with vasculitic or infectious death. Therefore, classification of clinical subtypes at the initial time and on admission is meaningful to some extent for predicting patient survival, kidney prognosis, and relapse, in addition to indicating the appropriate treatment regimen.