The Association of dyspnoea and quality of life in the BOLD study

<bold>Introduction:</bold> Dyspnoea seems to have an impact on health-related quality of life. However, evidence of this relationship is limited. We aimed to investigate the association of both physical and mental quality of life with dyspnoea across several low-, middle- and high-income sites. <bold>Methods:</bold> We analysed cross-sectional data from 19,744 adults, from 31 sites, participating in the Burden of Obstructive Lung Disease (BOLD) study who had provided information on the quality of their mental and physical health as well as on dyspnoea. We measured both quality of life components using the short-form 12 (SF-12) quality of life questionnaire, and defined dyspnoea as grade 2 or higher on the modified Medical Research Council (mMRC) scale. We assessed the association of each quality-of-life component with dyspnoea using linear regression, adjusted for potential confounders. To investigate differences in this association across low-, middle- and high-income study sites, we used random-effects meta-analysis. <bold>Results:</bold> We found that both physical and mental health component scores were lower in participants with dyspnoea compared to those without dyspnoea. This association was stronger for the physical component score (coefficient = -7.59; 95%CI -8.60, -6.58) than for the mental component score (coefficient = -3.50; 95%CI -4.36, -2.63). Heterogeneity in these associations was considerable across study sites. <bold>Conclusion:</bold> Quality of life is strongly affected by the presence of dyspnoea.