Multiple respiratory symptoms predict quality of life in chronic lung disease: A population-based study of Australian adults R.E. Run 1 , D.H. Wilson 2 , C.R. Chittleborough 2 , A.M. Southcott 3 , B. Smith 4 & D.J. Christopher 3 1 Department of Medicine, The University of Adelaide, The Queen Elizabeth Hospital Campus, South Australia; 2 Centre for Population Studies in Epidemiology, Department of Human Services, South Australia; 3 Department of Respiratory Medicine, The Queen Elizabeth Hospital, South Australia; 4 Clinical Epidem- iology and Health Outcomes Unit, The Queen Elizabeth Hospital, South Australia, Australia Accepted in revised form 10 December 2000 Abstract Study objectives: Previous studies have shown that it is possible to improve the health-related quality of life (HRQoL) of chronic lung disease (CLD) patients without a concurrent change in morbidity. A valid CLD index that discriminates between dierent levels of CLD severity and is associated with HRQoL status is an important tool for primary care settings. In this study 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 population survey of adults aged 18 years and over using a multistage, systematic, clustered area sample. Setting: Metropolitan Adelaide and country centres in South Australia with a population of over 1000 persons. Participants: Three hundred twenty-nine adults with CLD identi®ed through a representative population survey of 3010 South Aus- tralians. Measurements and Results: The 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. The CLD index was also used to assess the prevalence of CLD and the distribution of severity in self-reported CLD in the South Australian population. Each symptom sub-scale of the CLD index was signi®cantly correlated with all scales of the SF-36. The prevalence of CLD as measured by the CLD index was 7.7% (mild), 2.2% (moderate) and 1.0% (severe). Conclusions: In the Australian context the CLD index is a reliable patient interview instrument that can be used to assess the eects of CLD on general HRQoL, improve assessment, and lead to interventions for physicians and their patients. Key words: Chronic lung disease (CLD) severity, Health-related quality of life (HRQoL), Respiratory, Signs and symptoms Abbreviations: CLD ± chronic lung disease; FEV 1 ± forced expiratory volume in one sec; HRQoL ± health- related quality of life; MCS ± mental health component summary score; PCS ± physical health component summary score; PEFR ± peak expiratory ¯ow rate; SF-36 ± 36-item short form health survey Introduction In recent years two developments have in¯uenced the management of chronic lung disease (CLD). First, a number of studies have pointed to the fact that physiological measures of CLD do not provide an adequate assessment of the condition on the basis of which a management plan can be formulated [1±5]. FEV 1 and PEFR are important diagnostic measures and also good predictors of prognosis. However, they are poorly correlated with functional health and well-being as measured by health-related quality of life (HRQoL) measures [3±6]. In other words, physiological Quality of Life Research 9: 1031±1039, 2000. Ó 2001 Kluwer Academic Publishers. Printed in the Netherlands. 1031