Distinct predictors of peripheral neuropathy in antineutrophil cytoplasmic antibody-associated vasculitis: KEIO-vasculitis cohort.

OBJECTIVES

Peripheral neuropathy affects quality of life in patients with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis. Early recognition and treatment initiation are essential to prevent irreversible nerve damage. The aim of this study was to identify baseline factors associated with peripheral neuropathy in ANCA-associated vasculitis.

METHODS

A total of 111 consecutive patients with newly diagnosed, treatment-naïve, active ANCA-associated vasculitis were enrolled. Baseline characteristics were compared among the three groups: patients without peripheral neuropathy, with sensory neuropathy, and with sensorimotor neuropathy. Analysis was further stratified by disease subtypes (eosinophilic granulomatosis with polyangiitis, EGPA; granulomatosis with polyangiitis, GPA; microscopic polyangiitis, MPA).

RESULTS

Patients with EGPA (84.6 %) were most prone to having peripheral neuropathy compared with GPA (20.0 %) and MPA (28.9 %) (P < 0.001). Among patients with EGPA, baseline eosinophil counts showed a stepwise increase with peripheral neuropathy severity: 2340/μL in patients without peripheral neuropathy, 4276/μL with sensory neuropathy, and 11,859/μL with sensorimotor neuropathy (P = 0.004). The most useful cutoff values of baseline eosinophil counts to predict peripheral neuropathy and sensorimotor neuropathy were 2468/μL (sensitivity 90 % and specificity 75 %) and 6724/μL (sensitivity 80 % and specificity 71 %), respectively. In patients with GPA and MPA, the neutrophil-to-lymphocyte ratio tended to rise with increasing peripheral neuropathy severity, although the difference was not statistically significant.

CONCLUSION

Baseline eosinophil counts may be useful predictors for both the presence and motor involvement of peripheral neuropathy in patients with EGPA, highlighting their clinical utility and early risk stratification. In GPA and MPA, neutrophil-driven inflammation may contribute to peripheral neuropathy development.