The Depression, Anxiety, and Stress Scale (DASS-21) demonstrated validity in individuals with chronic obstructive pulmonary disease (COPD) underwent an 8-week pulmonary rehabilitation program, according to a study published in CHEST.
This study included 557 participants with COPD (mean age, 72±9.4 years). The pulmonary rehabilitation program was 2 hours per week: 1 hour of exercise and 1 hour of education. The modified Medical Research Council (nMRC) scale, St. George’s Respiratory Questionnaire (SGRQ), incremental shuttle walk test (ISWT), and Anxiety Inventory for Respiratory Disease (AIR) were used to take baseline and end-of-study measurements of dyspnea, quality of life, exercise capacity, and anxiety, respectively. Finally, researchers compared the responsiveness and validity of the DASS-21 with other scales, as it had not yet been validated in patients with COPD.
The baseline DASS metrics for depression, anxiety, and stress had a strong association with relative scores from the other metrics (P <.001 for all), but DASS-anxiety showed a weak correlation with ISWT (r=0.13; P <.001) and DASS-depression showed a weak correlation with forced expiratory volume in 1 second percentage (r=0.11; P =.03).
The DASS scale was responsive to pulmonary rehabilitation, as the DASS-depression score for those with depression scores >9 decreased by 5.49 (P <.001; effect size, 0.49); for anxiety scores >7, by 3.61 (P <.001; effect size, 0.54); and for stress scores >14, by 7.16 (P <.001; effect size, 0.81). Overall, the depression, anxiety, and stress subset of DASS-21 correlated strongly with SGRQ (P <.0001).
Study limitations included a lack of strong associations between variance in DASS scores and in quality of life and disease acuteness markers, no examination of DASS-21’s predictive power concerning emergency care use, and large effect sizes in participants with high anxiety, depression, and stress levels.
The researchers concluded that “the DASS-21 scale has acceptable validity and responsive scale to measure depression, anxiety, and stress in patients with COPD. Thus, further studies are needed to examine its validity across different populations, cultures, and races, predictive ability and efficacy in long-term follow-up after [pulmonary rehabilitation program].”
Yohannes AM, Dryden S, Hanania NA. The validity and responsiveness of the depression, anxiety and stress scale (DASS-21) in chronic obstructive pulmonary disease [published online December 27, 2018]. CHEST. doi:10.1016/j.chest.2018.12.010