Icatibant was efficacious and generally well tolerated for type I or II hereditary angioedema (HAE) attacks in adults in the phase III, randomized, placebo-controlled For Angioedema Subcutaneous Treatment (FAST)-3 trial. The Icatibant Outcome Survey (IOS) is an international, observational study assessing icatibant treatment of HAE attacks. We conducted a posthoc analysis to compare for the first time the treatment of HAE type I or II attacks in patients prescribed icatibant in real-world (IOS) versus controlled trial settings (FAST-3). In FAST-3, patients received icatibant administered by health care professionals (HCPs). In IOS, patients self-administered icatibant or were treated by HCPs. Median time to treatment, time to resolution (almost complete resolution [FAST-3] or complete resolution [IOS]), and attack duration in patients who were treated by an HCP were compared between IOS and FAST-3. Descriptive statistical methods compared nonlaryngeal attacks treated less than 12 hours from attack onset. Analysis included 102 patients (376 attacks) from IOS and 43 patients (43 attacks) from FAST-3 (controlled phase). All endpoints were significantly longer for patients in FAST-3 (HCP administration) versus IOS (HCP administration) (p < .001; all comparisons). For FAST-3 (HCP administered) versus IOS (HCP administered), median time from attack onset to treatment was 6.5 versus 2.0 hours, median time to symptom resolution was 8.0 versus 3.5 hours, and median attack duration was 16.9 versus 7.3 hours, respectively. For combined HCP and self-administration in IOS, these endpoints were 1.6, 4.4, and 7.8 hours, respectively. This posthoc analysis showed for the first time that type I and II HAE attacks were treated earlier with icatibant in a real-world versus a phase III setting, with a shortened time to symptom resolution and attack duration. ClinicalTrials.gov NCT00912093 (FAST-3); NCT01034969 (IOS).