Asthma exacerbations account for almost 2 million emergency department (ED) visits in the United States each year. In response to this problem, the NHLBI recently convened a working group to encourage clinical research in emergency asthma. With the help of an administrative supplement to his K14 award, Dr. Carlos Camargo proposed to initiate such research in the ED at Massachusetts General Hospital (Boston, MA). Over the past 24 months, this local project has grown into the Multicenter Asthma Research Collaboration (MARC), a research network involving 77 urban EDS across North America. MARC investigators have completed several prospective cohort studies and are currently performing a multicenter randomized trial. The objective of this application is to obtain funding for a full-time statistician to help 77 MARC investigators to study the epidemiology of emergency asthma. Five representative aims are: to characterize acute asthma management in urban EDs, and then compare current practice with that recommended in the 1997 national guidelines; to examine gender differences in acute asthma; to identify reasons why minority patients with asthma go to (and possibly prefer) the ED for their asthma care; to characterize important clinical subgroups, such as acute asthma among pregnant women and patients with sudden-onset severe acute asthma; and to examine risk factors for asthma hospitalization and for relapse after ED discharge. The MARC investigators are in an excellent position to address these aims. The study has a better design (prospective cohort) than most prior ED studies. Also, the network approach has yielded a large sample size (n=2,464) with excellent statistical power. Another advantage is the age range (ages 2-54), which not only allows investigation of children but also comparison of pediatric findings with results from comparable analyses among adults. Another advantage is that the PI is a well-trained and experienced investigator who works regularly with much larger datasets and has access to many experts in the field. The proposal satisfies all criteria of the Small Grants Program, as well as the NIH Review Criteria. Thus, we are confident that analysis of the MARC databases would make an important contribution to current understanding of emergency asthma.