Exploring dyspnea-related anxiety and physical activity in U.S. veterans with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) occurs in 8-19% of United States (U.S.) Veterans and is a leading cause of morbidity and mortality. Dyspnea, the main symptom of COPD, has been linked to both activity restriction and psychological symptoms, such as dyspnea-related anxiety (e.g., fear of dyspnea or fear of dyspnea-inducing activities). To date, however, associations between dyspnea-related anxiety symptoms, dyspnea severity, and objectively measured PA have not been explored in one model. In the current study, we tested a cross-sectional mediation model in which dyspnea severity mediates the association between dyspnea-related anxiety and PA. We hypothesized that higher levels of dyspnea-related anxiety would be associated with lower PA, and that dyspnea severity would partially or fully mediate this relationship. We performed cross-sectional analyses (correlation and simple mediation) of data collected from U.S. Veterans with COPD who were enrolled in a mixed-methods study within the VA Boston Healthcare System. Participants completed self-report measures of dyspnea-related anxiety (Breathlessness Beliefs Questionnaire) and dyspnea severity (University of California, San Diego Shortness of Breath Questionnaire). Physical activity was measured with accelerometer-derived step counts averaged over 14 +/- 1 days (ActiGraph wGT3X-BT). The mediation model was conducted using the SPSS macro for Hayes PROCESS Model 4. Complete data were available for 48/50 (96%) of enrolled participants. Six participants (12%) were excluded from analysis because their average daily step count exceeded the threshold for being active (≥ 10,000 steps/day). Forty-two Veterans were included in the analysis (88% White, 93% male) with a mean age of 69 +/- 6 years, mean forced expiratory volume in 1 s 67 +/- 21% predicted, and mean daily step count of 4,635 +/- 2,115 steps. Simple mediation analysis demonstrated a significant indirect effect of dyspnea-related anxiety on PA through dyspnea severity (point estimate = -0.26, 95% CI = [-0.43, -0.11]). After accounting for indirect effects, there was no significant main effect of dyspnea-related anxiety on PA (B = -27.62, p = .44), suggesting dyspnea levels completely mediated the relationship between dyspnea-related anxiety and PA. Greater dyspnea-related anxiety is associated with lower PA in U.S. Veterans with COPD, and this relationship may be influenced by Veterans' perception of dyspneic symptoms. Larger, longitudinal studies are needed to disentangle timing and direction of effects. Identifying subgroups of Veterans with COPD with elevated dyspnea-related anxiety may inform personalized exercise and behavioral interventions to improve dyspnea and PA.