Our object was to describe demographic data from a population of adult asthmatics admitted to a regional tertiary medical center to identify risk factors for intubation. We performed a retrospective cohort study of all asthma admissions (International Classification of Diseases, Ninth Revision, Code 493.9) excluding cases with chronic obstructive pulmonary disease. This included all patients with asthma 20 years and above admitted to the University of California Davis Medical Center, Sacramento, from January 1, 1990 to June 30, 1993. A total of 375 asthma admissions were reviewed. There were 244 women (29 intubated) and 131 men (13 intubated) with a mean age of 40.7 (range 20-72) years. Of this group, 131 people were white, 140 black, 56 Hispanic, 42 Asian, and 6 American Indian. By National Heart, Lung, and Blood Institute Guidelines, there were 101 mild, 181 moderate, and 93 severe cases. Significant risk parameters identified for intubation were psychosocial problems [odds ratio (O.R.) 9.3; 95% confidence interval (C.I.) 6.8, 12.7], low socioeconomic group (O.R. 2.9; 95% C.I. 1.5, 5.8), little formal education (O.R. 5.4; 95% C.I. 2.8, 10.2), atopic allergy (O.R. 11.7; 95% C.I. 5.7, 23.7), duration of asthma > or = 15 years (O.R. 2.6; 95% C.I. 1.3, 5.3), previous intubation (O.R. 14.0; 95% C.I. 7.6, 25.6), upper respiratory infection (O.R. 4.0; 95% C.I. 2.2, 7.5), hospital admission for asthma within the last year (O.R. 5.3; 95% C.I. 2.7, 10.4), emergency room visit within the last year (O.R. 8.8; 95% C.I. 3.9, 20.1), and steroid dependency (O.R. 5.5; 95% C.I. 3.0, 10.2).(ABSTRACT TRUNCATED AT 250 WORDS)