Co-Morbidity, Body Mass Index and Quality of Life in COPD Using the Clinical COPD Questionnaire

INTRODUCTION: Quality of life is an important patient-oriented measure in COPD. The Clinical COPD Questionnaire (CCQ) is a validated instrument for estimating quality of life. The impact of different factors on the CCQ-score remains an understudied area. The aim of this study was to investigate the association of co-morbidity and body mass index with quality of life measured by CCQ. METHODS: A patient questionnaire including the CCQ and a review of records were used. A total of 1548 COPD patients in central Sweden were randomly selected. Complete data were collected for 919 patients, 639 from primary health care and 280 from hospital clinics. Multiple linear regression with adjustment for sex, age, level of education, smoking habits and level of care was performed. Subanalyses included additional adjustment for lung function in the subgroup (n = 475) where spirometry data were available. RESULTS: Higher mean CCQ score indicating lower quality of life was statistically significant and independently associated with heart disease (adjusted regression coefficient (95%CI) 0.26; 0.06 to 0.47), depression (0.50; 0.23 to 0.76) and underweight (0.58; 0.29 to 0.87). Depression and underweight were associated with higher scores in all CCQ subdomains. Further adjustment for lung function in the subgroup with this measure resulted in statistically significant and independent associations with CCQ for heart disease, depression, obesity and underweight. CONCLUSION: The CCQ identified that heart disease, depression and underweight are independently associated with lower health-related quality of life in COPD.