title: Distinct symptom experiences in subgroups of patients with COPD.
abstract: BACKGROUND
  In addition to their respiratory symptoms, patients with COPD experience multiple, co-occurring symptoms.
  
  
  OBJECTIVE
  The aims of this study were to identify subgroups of COPD patients based on their distinct experiences with 14 symptoms and to determine how these subgroups differed in demographic and clinical characteristics and disease-specific quality of life.
  
  
  METHODS
  Patients with moderate, severe, and very severe COPD (n=267) completed a number of self-report questionnaires. Latent class analysis was used to identify subgroups of patients with distinct symptom experiences based on the occurrence of self-reported symptoms using the Memorial Symptom Assessment Scale.
  
  
  RESULTS
  Based on the probability of occurrence of a number of physical and psychological symptoms, three subgroups of patients (ie, latent classes) were identified and named "high", "intermediate", and "low". Across the three latent classes, the pairwise comparisons for the classification of airflow limitation in COPD were not significantly different, which suggests that measurements of respiratory function are not associated with COPD patients' symptom burden and their specific needs for symptom management. While patients in both the "high" and "intermediate" classes had high occurrence rates for respiratory symptoms, patients in the "high" class had the highest occurrence rates for psychological symptoms. Compared with the "intermediate" class, patients in the "high" class were younger, more likely to be women, had significantly more acute exacerbations in the past year, and reported significantly worse disease-specific quality of life scores.
  
  
  CONCLUSIONS
  These findings suggest that subgroups of COPD patients with distinct symptom experiences can be identified. Patients with a higher symptom burden warrant more detailed assessments and may have therapeutic needs that would not be identified using current classifications based only on respiratory function.
authors.affiliation: Division of Emergencies and Critical Care, Department of Research and Development, Oslo University Hospital, Ullevål; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo; Lovisenberg Diaconal University College.
authors.forename: Vivi L
authors.initials: VL
authors.lastname: Christensen
authors.affiliation: Institute of Clinical Medicine, Faculty of Medicine, University of Oslo; Department of Nursing Science, Institute of Health and Society, University of Oslo, Oslo, Norway.
authors.forename: Tone
authors.initials: T
authors.lastname: Rustøen
authors.affiliation: Department of Community Health Systems.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Cooper
authors.affiliation: Department of Physiological Nursing, University of California, San Francisco, CA, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Miaskowski
authors.affiliation: Department of Circulation and Medical Imaging, St Olav's University Hospital, Trondheim.
authors.forename: Anne H
authors.initials: AH
authors.lastname: Henriksen
authors.affiliation: Department of Health Studies, University of Stavanger, Stavanger.
authors.forename: Signe B
authors.initials: SB
authors.lastname: Bentsen
authors.affiliation: Institute of Clinical Medicine, Faculty of Medicine, University of Oslo; Department of Respiratory Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors.forename: Are M
authors.initials: AM
authors.lastname: Holm
mesh_terms: D000367:Age Factors; D000368:Aged; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009664:Norway; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D011788:Quality of Life; D012307:Risk Factors; D057566:Self Report; D012720:Severity of Illness Index; D012737:Sex Factors; D013997:Time Factors
keywords: COPD; latent class analysis; quality of life; symptom experience