The National Review of Asthma Deaths found that most patients who died were actually considered to have mild to moderate asthma, with 57% of fatal cases not under specialist care at the time of their death. In cases of fatal asthma there was widespread underuse of inhaled corticosteroids and an overreliance on short-acting beta-agonists. Referral to secondary care should take place when there is diagnostic uncertainty or atypical features, the possibility of hypersensitivity to inhaled material or concerns over treatment or exacerbations. Patients who have suffered even a single life-threatening asthma attack should be under specialist supervision.