Psychological predictors for health-related quality of life and disability in persons with chronic obstructive pulmonary disease (COPD).

Objective: Individuals with chronic obstructive pulmonary disease (COPD) exhibit low physical and mental health-related quality of life (HRQL) and high susceptibility to disability. We investigated the influence of psychological factors on HRQL and disability in COPD individuals recruited from the general population. In line with Leventhal's common sense model, we expected psychological factors to be associated with HRQL and disability even after controlling for medical status.
Methods: Individuals with COPD (n = 502; 59.7 years old; GOLD grades were I: 3%, II: 17%, III: 34%, IV: 46%) were assessed through an online survey administered via COPD patient organisations in Germany. Individuals filled in the Short Form Health Survey (SF-12), COPD Assessment Test, Patient Health Questionnaire (modules: GAD-2, PHQ-15, PHQ-9), Brief Illness Perception Questionnaire, a questionnaire that assesses causal illness attributions, and the internal illness-related locus of control scale of the 'KKG questionnaire for the assessment of control beliefs about illness and health'. Multiple linear regressions were calculated.
Results: The investigated factors explained high variances (disability = 56%, physical HRQL = 28%, mental HRQL = 63%, p ≤ .001). Better mental health, more optimistic illness perceptions, attribution to psychological causes, and stronger internal locus of control were associated with lower disability and better HRQL. Comorbid somatic symptoms contributed to high disability and low quality of life.
Conclusion: Psychological factors, such as illness perception, attribution and internal locus of control, were associated with disability and HRQL. These factors should be considered when designing treatments for individuals with COPD, and adequate interventions should be provided to enhance illness understanding and self-management skills.