This study investigated patient perceptions, experiences and management of COPD throughout the SLS COPD study. Follow-up interviews were conducted with 400 patients who completed SLS COPD; a mixed-methods approach was used to collect quantitative and qualitative information. Structured interviews using closed-ended questions were conducted with 360 patients, detailing aspects of background/lifestyle information and COPD. Extended interviews containing open-ended questions on perceptions of COPD and quality of life (QoL) in addition to the closed-ended questions were completed by 40 further patients. Participants also completed the Adherence Starts with Knowledge-12 (ASK-12) and the COPD and Asthma Sleep Impact Scale (CASIS) questionnaire. Quantitative data were analysed descriptively; qualitative data were analysed using qualitative description. The participants (n = 400) were reasonably representative of the SLS COPD population; mean age was 66.2 years. Breathlessness was the most commonly recalled symptom of/associated with COPD (88.5% of patients) and was the symptom that changed the most (improved, 26.8%/worsened, 20.9%) throughout the study. Participants' daily functioning and activities were most affected by symptoms of/associated with COPD, followed by relationships and psychological issues. 66.5% of participants experienced exacerbations, 60.5% of whom reported self-management as their first treatment strategy (taking antibiotics, resting and/or corticosteroids). Qualitative analysis revealed COPD symptoms, breathlessness in particular, to have a significant impact on mobility and in turn QoL. In conclusion, breathlessness was cited in these interviews as the COPD symptom with the greatest impact on participants' daily functioning, activities and self-care. The findings provided significant additional knowledge to the SLS COPD study findings.