Comparing acquired angioedema with hereditary angioedema (types I/II): findings from the Icatibant Outcome Survey

Abstract

Icatibant is used to treat acute hereditary angioedema with C1 inhibitor deficiency types I/II (C1-INH-HAE types I/II) and has shown promise in angioedema due to acquired C1 inhibitor deficiency (C1-INH-AAE). Data from the Icatibant Outcome Survey (IOS) were analysed to evaluate the effectiveness of icatibant in the treatment of patients with C1-INH-AAE and compare disease characteristics with those with C1-INH-HAE types I/II. Key medical history (including prior occurrence of attacks) was recorded upon IOS enrolment. Thereafter, data were recorded retrospectively at approximately 6-month intervals during patient follow-up visits. In the icatibant-treated population, 16 patients with C1-INH-AAE had 287 attacks and 415 patients with C1-INH-HAE types I/II had 2245 attacks. Patients with C1-INH-AAE versus C1-INH-HAE types I/II were more often male (69 versus 42%; P = 0·035) and had a significantly later mean (95% confidence interval) age of symptom onset [57·9 (51·33-64·53) versus 14·0 (12·70-15·26) years]. Time from symptom onset to diagnosis was significantly shorter in patients with C1-INH-AAE versus C1-INH-HAE types I/II (mean 12·3 months versus 118·1 months; P = 0·006). Patients with C1-INH-AAE showed a trend for higher occurrence of attacks involving the face (35 versus 21% of attacks; P = 0·064). Overall, angioedema attacks were more severe in patients with C1-INH-HAE types I/II versus C1-INH-AAE (61 versus 40% of attacks were classified as severe to very severe; P < 0·001). Median total attack duration was 5·0 h and 9·0 h for patients with C1-INH-AAE versus C1-INH-HAE types I/II, respectively.

Keywords: acquired angioedema; hereditary angioedema; icatibant.

Figure 1

Anatomical sites of angioedema attacks for C1‐INH‐AAE and C1‐INH‐HAE types I/II. Some patients experienced attacks at multiple locations, which is why totals may equal >100%. *P = 0·010. ^†Data missing for 60 attacks. C1‐INH‐AAE = angioedema due to acquired C1 inhibitor deficiency; C1‐INH‐HAE types I/II = hereditary angioedema with C1 inhibitor deficiency types I/II.

Figure 2

(a) Severity of angioedema attacks for C1‐INH‐AAE and C1‐INH‐HAE types I/II. Attacks were categorized as very mild, mild, moderate, severe, very severe or unknown severity. (b) Summary of (a), showing severity of angioedema attacks divided into two categories: very mild to moderate, and severe to very severe. *Data missing for 45 attacks; data unknown for seven attacks. ^†Data missing for 191 attacks; data unknown for 77 attacks. ^‡ P < 0·001. C1‐INH‐AAE = angioedema due to acquired C1 inhibitor deficiency; C1‐INH‐HAE types I/II = hereditary angioedema with C1 inhibitor deficiency types I/II.

Figure 3

Median times to first injection of icatibant and resolution of symptoms. Number of attacks: C1‐INH‐AAE, n = 73; C1‐INH‐HAE types I/II, n = 830. *P = 0·083. ^† P = 0·031. ^‡ P = 0·014. C1‐INH‐AAE = angioedema due to acquired C1 inhibitor deficiency; C1‐INH‐HAE types I/II = hereditary angioedema with C1 inhibitor deficiency types I/II.