DIAGNOSED AND POSSIBLE UNDIAGNOSED ASTHMA - A WISCONSIN-RESEARCH-NETWORK (WREN) STUDY

Background. Adult-onset asthma is frequently encountered in primary ca re and is responsible for a large proportion of asthma morbidity and m ortality. The primary goal of this survey was to describe the epidemio logy of diagnosed and possible undiagnosed asthma in Wisconsin Researc h Network (WReN) practices. Methods. Physicians from 59 practices inte rviewed a systematic sample of their clinical population, which includ ed all patients encountered during office visits one day each week for 3 or 12 months, to obtain a history of physician-diagnosed asthma or symptoms suggesting undiagnosed asthma (wheezing and shortness of brea th). Age at diagnosis or at onset of symptoms and current disease acti vity were also recorded. Results. The 14,127 patients surveyed closely resembled the age-sex composition of the 1990 general and family prac tice component of the National Ambulatory Medical Care Survey. Physici an-diagnosed asthma that was active within the previous year was repor ted by 6.1% of WReN patients (5.8% of patients younger than 20 years o f age and 6.2% of adults). Undiagnosed asthma that was active within t he previous year was reported by 3.3% (2.9% of patients younger than 2 0 pears of age and 3.4% of adults). Adult-onset asthma was reported by 46.3% of all patients with diagnosed asthma; and 56.7% of patients wi th undiagnosed asthma reported that their symptoms began in adulthood. Conclusions. Adult-onset asthma accounts for approximately one half o f all asthma cases. Since most patients with adult-onset asthma are ma naged by primary care physicians, practice-based research is necessary for the understanding, treatment, and possible prevention of this imp ortant disease.