Risk factors for death in patients with severe asthma

Objective: To identify risk factors for death among patients with severe asthma. Methods: This was a nested case-control study. Among the patients with severe asthma treated between December of 2002 and December of 2010 at the Central Referral Outpatient Clinic of the Bahia State Asthma Control Program, in the city of Salvador, Brazil, we selected all those who died, as well as selecting other patients with severe asthma to be used as controls (at a ratio of 1:4). Data were collected from the medical charts of the patients, home visit reports, and death certificates. Results: We selected 58 cases of deaths and 232 control cases. Most of the deaths were attributed to respiratory causes and occurred within a health care facility. Advanced age, unemployment, rhinitis, symptoms of gastroesophageal reflux disease, long-standing asthma, and persistent airflow obstruction were common features in both groups. Multivariate analysis showed that male gender, FEV1 pre-bronchodilator < 60% of predicted, and the lack of control of asthma symptoms were significantly and independently associated with mortality in this sample of patients with severe asthma. Conclusions: In this cohort of outpatients with severe asthma, the deaths occurred predominantly due to respiratory causes and within a health care facility. Lack of asthma control and male gender were risk factors for mortality.