Prognosis
International asthma mortality is reported as high as 0.86 deaths per 100,000 persons in some countries. US asthma mortality rates in 2006 were reported at 1.2 deaths per 100,000 persons. Mortality is primarily related to lung function, with an 8-fold increase in patients in the lowest quartile, but mortality has also been linked with asthma management failure, especially in young persons. Other factors that impact mortality include age older than 40 years, cigarette smoking more than 20-pack years, blood eosinophilia, forced expiratory volume in one second (FEV1) of 40-69% predicted, and greater reversibility.[36]