Predictors of dyspnoea prevalence: results from the BOLD study

Abstract

Dyspnoea is a cardinal symptom for cardiorespiratory diseases. No study has assessed worldwide variation in dyspnoea prevalence or predictors of dyspnoea. We used cross-sectional data from population-based samples in 15 countries of the Burden of Obstructive Lung Disease (BOLD) study to estimate prevalence of dyspnoea in the full sample, as well as in an a priori defined low-risk group (few risk factors or dyspnoea-associated diseases). Dyspnoea was defined by the modified Medical Research Council questions. We used ordered logistic regression analysis to study the association of dyspnoea with site, sex, age, education, smoking habits, low/high body mass index, self-reported disease and spirometry results. Of the 9484 participants, 27% reported any dyspnoea. In the low-risk subsample (n=4329), 16% reported some dyspnoea. In multivariate analyses, all covariates were correlated to dyspnoea, but only 13% of dyspnoea variation was explained. Females reported more dyspnoea than males (odds ratio ∼2.1). When forced vital capacity fell below 60% of predicted, dyspnoea was much more likely. There was considerable geographical variation in dyspnoea, even when we adjusted for known risk factors and spirometry results. We were only able to explain 13% of dyspnoea variation.

©ERS 2014.

Figures

Figure 1. Prevalence of mMRC-defined dyspnea grades by site in 15 countries of the BOLD study.

Figure 2. Prevalence of mMRC grade 2 or higher dyspnea by FVC (% predicted) and FEV1/FVC (% predicted) in participants with a lower risk for dyspnea (stapled lines), and subjects with higher risk for dyspnea (solid lines), stratified by sex.

See the text or footnotes of Table 2 for the definition the low-risk group and for number of participants.

Figure 3. Box-plot of FVC % predicted by mMRC dyspnea.

The box represents the interquartile range (IQR), the line within the box is the median value and the whiskers shows values within 1.5 IQR of the adjacent quartile. Outliers are plotted.

Figure 4. Odds ratio (logistic regression) for mMRC 2 and higher dyspnea at different levels of FVC of % predicted.

Adjusted for all covariates in table 3 except lung function variables. N=9,334.

Figure 5. Odds ratio (logistic regression) for mMRC 2 and higher dyspnea at different levels of FEV1/FVC (% predicted, not absolute).

Adjusted for all covariates in table 3 except lung function variables. N= 9,334.