Risk Factors for Death in Adults with Severe Asthma

Background: Mortality risk in adult asthma is poorly understood, especially the interplay among race, disease severity, and health care access.

Objective: To examine mortality risk factors in adult asthma.

Methods: In a prospective cohort study of 865 adults with severe asthma in a closed-panel managed care organization, we used structured interviews to evaluate baseline sociodemographics, asthma history, and health status. Patients were followed up until death or the end of the study (mean, 2 years). We used Cox proportional hazards regression to evaluate the impact of sociodemographics, cigarette smoking, and validated measures of perceived asthma control, physical health status, and severity of asthma on the risk of death.

Results: We confirmed 123 deaths (mortality rate, 6.7 per 100 person-years). In an analysis adjusted for sociodemographics and tobacco history, higher severity-of-asthma scores (hazard ratio [HR], 1.11 per 0.5-SD increase in severity-of-asthma score; 95% confidence interval [CI], 1.01-1.23) and lower perceived asthma control scores (HR, 0.91 per 0.5-SD increase in perceived asthma control score; 95% CI, 0.83-0.99) were each associated with risk of all-cause mortality. In the same adjusted analysis, African American race was not associated with increased mortality risk relative to white race (HR, 0.64; 95% CI, 0.36-1.14).

Conclusions: In a large managed care organization in which access to care is unlikely to vary widely, greater severity-of-asthma scores and poorer perceived asthma control scores are each associated with increased mortality risk in adults with severe asthma, but African American patients are not at increased risk for death relative to white patients.