The impact of affective states on the perception of dyspnea in patients with chronic obstructive pulmonary disease

Abstract

Dyspnea is the cardinal symptom of chronic obstructive pulmonary disease (COPD). Affective states can profoundly impact upon the perception of dyspnea, but little is known about this relationship in patients with COPD. We, therefore, examined the impact of viewing positive versus negative affective picture series on perceived dyspnea during two cycle ergometer exercise tests (CEET) in 30 patients with COPD. Whereas cardiopulmonary measures indicated comparable exercise intensity during both CEETs, parallel viewing of negative affective pictures resulted in increased dyspnea ratings compared to positive affective pictures. Regression analyses showed that only during positive picture viewing increases in the affective unpleasantness of dyspnea, but not in the sensory intensity of dyspnea, during CEETs were predictive of greater dyspnea during everyday activities and reduced health-related quality of life. The results suggest that negative affective states increase perceived dyspnea in patients with COPD and underline the importance of targeting the affect–dyspnea-relationship in this patient group.

Introduction

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease with significant extrapulmonary (systemic) effects, which is characterized by not fully reversible and usually progressive airflow limitation based on abnormal inflammatory response of the lung to noxious particles or gases (GOLD, 2008). COPD is a leading cause of morbidity and mortality worldwide and associated with significant social and economic burden as well as considerable reductions in patients’ quality of life (GOLD, 2008, Ries, 2006). The prevalence and burden of COPD are projected to dramatically increase in the coming decades. For example, the Global Burden of Disease study concludes that COPD worldwide will increase from 1990 to 2020 its rank number of death rising from rank 6 to rank 3, and its rank number of disability-adjusted life years lost from rank 12 to rank 5 (Lopez and Murray, 1998, Murray and Lopez, 1996). The cardinal symptom of COPD is dyspnea (breathlessness), the subjective experience of uncomfortable breathing (American Thoracic Society, 1999, GOLD, 2008). At early stages of COPD, dyspnea usually develops during physical activities and exercise, whereas at later stages of the disease, it is already present at rest. The experience of this frightening sensation often leads to activity avoidance, deconditioning and subsequently greater dyspnea at lower activity levels (GOLD, 2008).

A growing body of literature suggests that psychological factors such as emotions, previous experiences, attributions, contextual, attentional and learning processes can profoundly impact the perception of dyspnea, often independent of changes in the respiratory system (Chetta et al., 2005, De Peuter et al., 2004, Lehrer et al., 2002, Rietveld and Creer, 2003, von Leupoldt and Dahme, 2007). Particularly affective states and negative emotions have been demonstrated to be associated with inadequate reporting of dyspnea. Previous studies in healthy volunteers and patients with asthma have shown that individuals characterized by high negative emotionality report more dyspnea or respiratory sensations than those with low negative emotionality, regardless of their respiratory status (Bogaerts et al., 2005, De Peuter et al., 2008, Han et al., 2004, Li et al., 2006, Put et al., 2004, Vögele and von Leupoldt, 2008). Similarly, the experimental induction of negative affective states in healthy individuals and patients led to increased reports of respiratory sensations such as dyspnea (Bogaerts et al., 2005, Rietveld and Prins, 1998, von Leupoldt et al., 2006a, von Leupoldt et al., 2006b, von Leupoldt et al., 2008). In particular the affective unpleasantness of perceived dyspnea, rather than the sensory intensity of perceived dyspnea, has been suggested as being vulnerable for affective influences (De Peuter et al., 2007, von Leupoldt et al., 2006a, von Leupoldt et al., 2008) and as being important in patients’ everyday life (Banzett et al., 2000, Lansing et al., 2009). However, little is known about the influence of affective states on the perception of dyspnea in patients with COPD (Nici et al., 2006, O’Donnell et al., 2007). Specifically in this patient group, a strong affect–dyspnea-relationship can be assumed, given the high prevalence of comorbid anxiety and depression in patients with COPD (Hill et al., 2008, Maurer et al., 2008, Mikkelsen et al., 2004, Vögele and von Leupoldt, 2008), which is further associated with less favourable treatment outcome and negative course of disease (Dahlen and Janson, 2002, Ng et al., 2007, Xu et al., 2008).

Therefore, the present study examined the impact of affective states on the perception of dyspnea in patients with mild to severe COPD. Affective states were induced by viewing affective picture series of positive and negative valence while dyspnea was simultaneously elicited by two constant cycle ergometer exercise tests (CEET). Based on the above reported previous findings in healthy individuals and patients with asthma, we hypothesized greater dyspnea ratings during a negative compared to a positive affective state. In addition, we studied the differential relationships of the affective unpleasantness versus the sensory intensity of exercise induced dyspnea with symptoms during everyday life and with health-related quality of life (HRQL).