The purpose of the study is to determine the efficacy of mindfulness-based cognitive therapy (MBCT) as an add-on to pulmonary rehabilitation (treatment as usual, TAU) in chronic obstructive pulmonary disease (COPD).

The investigators hypothesize that compared to treatment-as-usual, the add-on of MBCT will result in improved psychological (anxiety, depression) and physical outcomes (physical health status, activity level, inflammatory markers). Furthermore, the investigators will explore the possible moderating role of individual differences in sociodemographic and disease-related characteristics and the perceived quality of the therapeutic alliance, as well as the mediating role of mindfulness, breathlessness catastrophizing, self-efficacy, and self-compassion for the hypothesised effect.

Chronic obstructive pulmonary disease (COPD) is a major burden for the affected patients, who are continuously struggling with the hallmark symptoms breathlessness, cough, and sputum together with high levels of anxiety and depression and impairment of quality of life (QoL). The potential value of complementary interventions in COPD has long been recognised, yet so far, no overall significant effects of psychosocial intervention programs such as cognitive behavioural therapy or supportive/analytical psychotherapy have been found.

Mindfulness-based interventions have been shown to improve levels of physical symptoms, stress, anxiety, depression, and QoL in other chronic conditions, and could also be relevant in COPD. The present randomized controlled trial will test the efficacy of mindfulness-based cognitive therapy (MBCT) in COPD patients. The investigators hypothesize that compared to treatment-as-usual, the add-on of MBCT will result in improved psychological (anxiety, depression) and physical outcomes (physical health status, activity level, inflammatory markers). Furthermore, the investigators will explore the possible moderating role of individual differences in sociodemographic and disease-related characteristics and the perceived quality of the therapeutic alliance, as well as the mediating role of mindfulness, breathlessness catastrophizing, self-efficacy, and self-compassion for the hypothesised effect.

Patients recruited from the Department of Respiratory Medicine, Aarhus University Hospital, will be randomized to participate in either an 8-week MBCT program as an add-on to the already established pulmonary rehabilitation program (intervention group) or pulmonary rehabilitation only (treatment-as-usual). Questionnaires assessing outcomes, mediators and moderators will be completed before, during, and after the intervention as well as at a 3 and 6 mo. follow-up.

This study will be one of the first to test the efficacy of MBCT in COPD, bringing attention to a patient group that is relatively ignored by the public as well as in the health psychological empirical literature.

After data collection, but prior to analysis, inaccuracies in the content of the registration were discovered. Some changes made prior to recruitment of the first participant had not been registered. The inaccuracies were amended in an update, 15 February 2017: 1) The primary outcome measure of iBODE (objective physical health status) was omitted (no data were collected). 2) The time frame for primary outcomes was changed from "Baseline, week 8" to "Baseline, 6 mo. follow-up". 3) Prior to data collection, three variables to be included in moderator and mediator analyses were added (therapeutic working alliance, mindfulness, and breathlessness catastrophizing).

Inclusion Criteria:

• severe to very severe COPD
• motivated to participate in pulmonary rehabilitation
• sufficient mobility to attend pulmonary rehabilitation

Exclusion Criteria:

• certain comorbidities (e.g. unstable coronary complications, psychiatric illness)
• severe cognitive disability (e.g. dementia)
• inability to speak Danish