- Adams R, Wilson D, Appleton S, Taylor A, Dal Grande E, Chittleborough C, et al. Underdiagnosed asthma in South Australia. Thorax. 2003;58:846-50 pubmed..Health service use over the previous year was similar for both asthma groups. Undiagnosed asthma is common among the Australian population, with a similar clinical spectrum to those with diagnosed asthma. ..