METHODS: The literature search of PubMed consisted of the following terms and their variations: trigger, prodromal symptom, predict, variable, breakthrough, fear, functioning, activities, daily life, spontaneous, travel, anxiety, impairment, certainty, productivity, absenteeism, work, future attack, worry, and episodic. Article abstracts were reviewed for relevance to the predictability of attacks in patients with HAE.
RESULTS: The search returned 312 articles, of which 79 were identified to be potentially relevant to the predictability of HAE. In two studies that asked patients about the predictive utility of prodromal symptoms, most patients were not able to predict attacks reliably. However, 85% and 91% of patients, respectively, stated that attacks were preceded by prodromal symptoms at least half of the time. No studies prospectively evaluated the positive predictive value of prodromal symptoms. Attacks are not predictable over the long term, which causes anxiety about future attacks and impairs patients’ ability to maintain employment, be productive, and conduct daily activities.
CONCLUSIONS: Patients can predict some attacks over the short term using prodromal symptoms, but the prevalence and characteristics of prodromes are highly variable. HAE symptoms are not predictable over the long term, which negatively affects patients’ quality of life. The unpredictability of HAE symptoms should be considered when establishing HAE treatment plans.