MPO and vasculitis: There are several cohorts that showed a higher mortality rate in patients with MPO-ANCA than those with patients with PR3-ANCA, but this difference is usually not statistically significant after adjustment for age, mostly because there seems to be a 10-year discrepancy between the two groups of patients; PR3-ANCA(+) vasculitis is common among 45–55-year-old patients, while MPO-ANCA(+) vasculitis is common in 60–65-year-old patients (13, 23, 24).