Multiple respiratory symptoms predict quality of life in chronic lung disease: A population-based study of Australian adults

Study objectives: Previous studies have shown that it is possible to improv e the health-related quality of life (HRQoL) of chronic lung disease (CLD) patients without a concurrent change in morbidity. A valid CLD index that d iscriminates between different levels of CLD severity and is associated wit h HRQoL status is an important tool for primary care settings. In this stud y a symptom-based CLD index was assessed for its validity and relationship with HRQoL in a representative Australian population sample. The study also measured the prevalence of self-reported CLD. Design: Representative popul ation survey of adults aged 18 years and over using a multistage, systemati c, clustered area sample. Setting: Metropolitan Adelaide and country centre s in South Australia with a population of over 1000 persons. Participants: Three hundred twenty-nine adults with CLD identified through a representati ve population survey of 3010 South Australians. Measurements and Results: T he CLD index and the SF-36 were administered to participants to assess the association between each subscale of the CLD index with each HRQoL scale. T he CLD index was also used to assess the prevalence of CLD and the distribu tion of severity in self-reported CLD in the South Australian population. E ach symptom sub-scale of the CLD index was significantly correlated with al l scales of the SF-36. The prevalence of CLD as measured by the CLD index w as 7.7% (mild), 2.2% (moderate) and 1.0% (severe). Conclusions: In the Aust ralian context the CLD index is a reliable patient interview instrument tha t can be used to assess the effects of CLD on general HRQoL, improve assess ment, and lead to interventions for physicians and their patients.