What Do Gastroenterologists Know About Hereditary Angioedema? Results of a 2012 Digestive Disease Week (DDW) Survey

Abstract

Purpose: The genetic disorder hereditary angioedema (HAE) results from deficient C1-inhibitor (C1-INH) activity and causes unpredictable acute angioedema attacks. Attacks affecting the gastrointestinal tract may cause severe, debilitating abdominal pain with nausea, vomiting, and/or diarrhea. Given its rarity (estimated prevalence of 1:50,000) and varied clinical presentation, diagnosis of HAE can take an average of 8 years from onset of first clinical symptoms. While diagnosed HAE patients are usually managed by allergists, the predominance of abdominal symptoms prompted us to assess whether gastroenterologists diagnose, treat, or follow these patients. Methods: A survey was conducted by HRA - Healthcare Research & Analytics during Digestive Disease Week (DDW) 2012. Participants (U.S.-based gastroenterologists or fellows or nurse practitioners in a GI practice) were recruited from the exhibit hall to complete a 5 minute survey; additional respondents were recruited online following DDW. Participants were asked about their awareness of HAE. Those who reported screening for HAE were also asked about the diagnosis and treatment of these patients. Results: A total of 115 gastroenterology practitioners completed the survey. A total of 94 respondents (82%) were gastroenterologists in practice >2 years (mean: 17.1 years); the remaining 18% were either in practice ≤2 years (n=10) or were nurse practitioners (n=2) or fellows (n=9). Overall, 97% of respondents were aware of HAE, 46% had never tested for it, and 22% screened for it but never diagnosed it. Sixty-two respondents (54%) screened for HAE, with a majority (90%) using the C1-INH blood test. Of the 62 who screened for HAE, 37 (60%) diagnosed patients with HAE; 62% of those reported diagnosing ≤5 patients while 5% reported diagnosing >50 patients. Following a diagnosis, 43% of the 37 respondents who have diagnosed referred the patient to another specialist for treatment and follow up (15 of the 16 respondents referred to an allergist); however, 30% of those diagnosing treated and followed the HAE patients themselves. Conclusion: The vast majority of gastroenterologists are aware of HAE, with nearly half (49%) testing their patients for the disease using the appropriate diagnostic test. A third of gastroenterology practitioners reported diagnosing HAE at some point during their practice, and a surprising number of those who have diagnosed HAE (30%) report treating those patients instead of referring them. Given that several new treatments directed at the underlying disease are now approved in the United States, this survey supports targeted education of gastroenterologists about the disease and new treatment options. Disclosure: Dr. Stevens - Consultant for Dyax Corp. Mr. Linder - Full-time employee of Dyax Corp. Dr. Soo - Full-time employee of Dyax Corp. This research was supported by an industry grant from Dyax Corp. paid a commercial entity (Healthcare Research and Analytics, HRA) to conduct the survey and perform the analysis.