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Published on: June 23, 2015
Clinical phenotypes and prognoses of microscopic polyangiitis based on kidney biopsies
Juan Wang1, Rui Li1, Wenyan Zhou2
1Department of Rheumatology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Background:
To classify the different clinical phenotypes and compare the distinct prognoses of microscopic polyangiitis (MPA).
Methods:
A retrospective analysis of 436 patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) from 2015 to 2022 was conducted in our center, of which 90 patients were diagnosed with MPA and underwent renal biopsy.
Results:
Among the 90 MPA patients, 63% were female, and the median age at onset was 63 years (25th-75th percentile: 58-68). The median follow-up time was 26 months (25th-75th percentile: 10-53). We identified four subtypes: renal impairment type (cluster 1, 39%), pure type (cluster 2, 22%), systemic inflammation type (cluster 3, 26%), and rapid progress type (cluster 4, 13%). Cluster 1, characterized by renal dysfunction at onset (80%), demonstrated poor prognoses with only 26% achieved complete remission (CR), 11% dying, and 19% developing renal failure. In contrast, patients in cluster 2, exclusively female, most had only kidney involvement showed the best prognoses with 55% achieving CR and none experiencing death or renal failure within 10 years. Cluster 3 mostly consisted of males; high fever and C-reactive protein levels were the primary characteristics. These cases exhibited moderate prognoses with 53% achieving CR, 9% dying, and 4% developing renal failure. Finally, patients in cluster 4, which was characterized by rapidly progressive glomerulonephritis, had the worst prognoses, with none achieving CR, 8% dying, and 75% developing renal failure despite aggressive treatment.
Conclusions:
MPA is classified into four subtypes with distinct clinical manifestations and prognoses.
Insights
Microscopic polyangiitis (MPA) can be classified into four distinct subtypes, each with unique clinical features and prognoses. Understanding these subtypes aids in predicting patient outcomes and tailoring treatment strategies for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis.
Area of Science:
- Nephrology
- Rheumatology
- Immunology
Background:
- Microscopic polyangiitis (MPA) is a form of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).
- Accurate classification of MPA phenotypes is crucial for understanding disease prognosis.
Purpose of the Study:
- To classify distinct clinical phenotypes of microscopic polyangiitis (MPA).
- To compare the prognoses associated with different MPA subtypes.
Main Methods:
- Retrospective analysis of 90 MPA patients who underwent renal biopsy.
- Patient data collected between 2015 and 2022.
- Clustering analysis to identify distinct patient subgroups.
Main Results:
- Four MPA subtypes were identified: renal impairment (39%), pure (22%), systemic inflammation (26%), and rapid progress (13%).
- The renal impairment subtype showed poor prognosis (26% complete remission, 19% renal failure).
- The pure subtype (exclusively female) had the best prognosis (55% complete remission, no renal failure within 10 years).
- Systemic inflammation subtype had moderate prognosis (53% complete remission).
- Rapid progress subtype had the worst prognosis (0% complete remission, 75% renal failure).
Conclusions:
- Microscopic polyangiitis can be classified into four distinct subtypes.
- These subtypes exhibit significantly different clinical manifestations and prognoses.
- Classification aids in predicting patient outcomes in ANCA-associated vasculitis.
