Association of five-factor score with the mortality in Japanese patients with polyarteritis nodosa

Aim: To determine mortality and its predictive factors in Japanese patients with polyarteritis nodosa (PAN).Methods: This retrospective single-center study determined the mortality of 18 patients with PAN who were admitted to Juntendo University Hospital from 1994 to 2016. The variables at baseline, including patient demographics, clinical characteristics, and treatment, were analyzed for their association with mortality.Results: The median age of onset was 57.0 years. The 1-year survival rate was 100% (16/16) and the 5-year survival rate was 80.0% (8/10). The relationship between mortality, as defined by the survival rate and each variable was evaluated by Cox univariate analysis. A higher 2009 five-factor score (FFS) was associated with increased mortality, with a hazard ratio of 2.34 (p=.04). Analysis of the secondary outcome of relapse-free survival time revealed an association with rapid progressive renal failure, Birmingham Vasculitis Activity Score (BVAS), the 1996 FFS, and the 2009 FFS, with hazard ratios of 7.28 (p=.048), 1.26 (p=.02), 2.32 (p=.03), and 1.82 (p=.04), respectively.Conclusion: We investigated mortality, relapse-free survival, and their predictive factors in Japanese patients with PAN. The BVAS and the 1996 FFS at diagnosis may be prognostic factors for relapse-free survival, and the 2009 FFS at diagnosis may be a prognostic factor for both mortality and relapse-free survival.