Risk factors associated with relapse or infectious complications in Japanese patients with microscopic polyangiitis.

BACKGROUND: The prevention of relapse and infection complications during remission maintenance therapy is required to improve the prognosis of patients with microscopic polyangiitis (MPA) showing rapidly progressive glomerulonephritis (RPGN). The clinicopathological characteristics of patients with ANCA-positive MPA were examined to determine the risk factors for relapse or infectious complications after remission induction therapy. PATIENTS AND METHODS: The study population consisted of 52 patients diagnosed as ANCA-positive MPA showing RPGN from 2002 to 2012, after publication of the Japanese guideline for RPGN. The clinicopathological findings were examined between the presence and absence of relapse or infectious complications. RESULTS: The value of vasculitis damage index (VDI) was high for the relapse group and VDI value was identified as the leading factor associated with relapse [hazard ratio (HR) 3.36, 95 % confidence interval (CI) 1.58-7.12, P < 0.01]. On the other hand, the values of Birmingham Vasculitis Activity Score, clinical grade category of RPGN at diagnosis, and VDI at remission were high in the infectious group. Furthermore, clinical grade category of RPGN was the leading factor associated with infectious complications (HR 5.30, 95 % CI 1.41-19.9, P = 0.01). CONCLUSION: The disease activity at diagnosis and severity of organ damage at remission were associated with relapse and infectious complications during remission maintenance therapy and infectious complication affected kidney survival and all-cause mortality in patients with ANCA-positive MPA exhibiting RPGN.