Symptom clusters and quality of life in subjects with COPD

BACKGROUND: COPD is one of the most common respiratory diseases. Patients with COPD experience and suffer from various physical and psychological symptoms. We performed this study to identify symptom clusters and the effects on quality of life (QOL) in patients with COPD. METHODS: A total of 130 COPD subjects were recruited from a university hospital in South Korea. Dyspnea, fatigue, depression, anxiety, sleep disturbance, dry mouth, and physical functional status were assessed with structured questionnaires. QOL was measured with the Clinical COPD Questionnaire. Factor analysis and cluster analysis were used to identify symptom clusters based on severity of symptom experiences. RESULTS: Three distinct clusters were identified: a respiratory-functional cluster (symptom cluster 1), a mood cluster (symptom cluster 2), and a fatigue-sleep cluster (symptom cluster 3). Symptom cluster 1 consisted of dyspnea, physical functional status, and dry mouth; symptom cluster 2 consisted of anxiety and depression; and symptom cluster 3 consisted of sleep disturbance and fatigue. Subgroup cluster analysis showed that COPD subjects with higher-scoring symptoms in symptom clusters 1, 2, and 3 had significantly poorer QOL. The symptom clusters were significantly different depending on age, educational level, and monthly income. CONCLUSIONS: COPD subjects may have specific patterns of symptom clusters. The symptom clusters are related with clinical characteristics and had a negative impact on QOL. To enhance symptom management and QOL, approaches and interventions based on symptom clusters, rather than independent intervention for each symptom, may be more effective. Understanding COPD symptom clusters may help successful symptom management, which can improve QOL for COPD patients.