Chronic Obstructive Pulmonary Disease Symptom Cluster Composition, Associated Factors, and Methodologies: A Systematic Review.

The review included only 10 studies, and it could not combine them in meta-analysis because sample characteristics, designs, and outcomes differed. Nine studies were cross-sectional and one was longitudinal, so most did not show how symptom clusters change over time. No qualitative study explored patient experience of symptom clusters, so the review lacks patients' own accounts of what these clusters mean. The included studies used different symptom instruments, dimensions, and statistical methods, so cluster composition varied and may not be comparable. COPD severity was not reported in four studies, so the findings cannot be tied to a definite disease severity measure. The samples were older and mostly male, and no pediatric population was studied, so results may not apply to younger or female patients. Quality was variable: mean AXIS score 16.3, range 11 to 19; only four studies justified sample size, and two had no selection process. Only English and Chinese articles were searched, so relevant work in other languages may be missing.

The authors declared no potential conflicts of interest. The study received funding from the China Scholarship Council, grant number 201806170005.

Do not use these clusters as a validated assessment or management tool. The review found inconsistent cluster definitions across mostly cross-sectional studies, used different instruments and methods, and did not establish a gold standard symptom cluster measure.