COL18A1 and hereditary angioedema: Over the course of a mean (SD) 4.5 (1.66) years of follow-up (from IOS entry until date of data extract or discontinuation) for patients with HAE-1/2, and a mean (SD) 4.3 (1.42) years of follow-up for patients with HAE nC1-INH, the maximum number of attacks reported per patient was higher in patients with HAE-1/2 (29 attacks) than in those with HAE nC1-INH (17 attacks) (Table 2).