BODE index versus GOLD classification for explaining anxious and depressive symptoms in patients with COPD – a cross-sectional study

Funk Georg-Christian, Burghuber Otto, Hartl Sylvia, Kirchheiner Kathrin, Hartl

Description

Anxiety and depression are common and treatable risk factors for re-hospitalisation and death in patients with COPD. The degree of lung function impairment does not sufficiently explain anxiety and depression. The BODE index allows a functional classification of COPD beyond FEV 1 . The aim of this cross-sectional study was (1) to test whether the BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms; and (2) to assess which components of the BODE index are associated with these psychological aspects of COPD. Methods COPD was classified according to the GOLD stages based on FEV 1%predicted in 122 stable patients with COPD. An additional four stage classification was constructed based on the quartiles of the BODE index. The hospital anxiety and depression scale was used to assess anxious and depressive symptoms. Results The overall prevalence of anxious and depressive symptoms was 49% and 52%, respectively. The prevalence of anxious symptoms increased with increasing BODE stages but not with increasing GOLD stages. The prevalence of depressive symptoms increased with both increasing GOLD and BODE stages. The BODE index was superior to FEV 1%predicted for explaining anxious and depressive symptoms. Anxious symptoms were explained by dyspnoea. Depressive symptoms were explained by both dyspnoea and reduced exercise capacity. Conclusion The BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms in COPD patients. These psychological consequences of the disease may play a role in future classification systems of COPD.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2009
• Nombre de lectures: 9
• Langue: English

Extrait

BioMed CentralRespiratory Research
Open AccessResearch
BODE index versus GOLD classification for explaining anxious and
depressive symptoms in patients with COPD – a cross-sectional
study
Georg-Christian Funk, Kathrin Kirchheiner, Otto Chris Burghuber* and
Sylvia Hartl
Address: Department of Respiratory and Critical Care Medicine and Ludwig Boltzmann Institute for Chronic Obstructive Pulmonary Disease, Otto
Wagner Hospital, Vienna, Austria
Email: Georg-Christian Funk - [e-mail]; Kathrin Kirchheiner - [e-mail];
Otto Chris Burghuber* - [e-mail]; Sylvia Hartl - [e-mail]
* Corresponding author
Published: 9 January 2009 Received: 13 October 2008
Accepted: 9 January 2009
Respiratory Research 2009, 10:1 doi:10.1186/1465-9921-10-1
This article is available from: http://respiratory-research.com/content/10/1/1
© 2009 Funk et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Background: Anxiety and depression are common and treatable risk factors for re-hospitalisation
and death in patients with COPD. The degree of lung function impairment does not sufficiently
explain anxiety and depression. The BODE index allows a functional classification of COPD beyond
FEV . The aim of this cross-sectional study was (1) to test whether the BODE index is superior to1
the GOLD classification for explaining anxious and depressive symptoms; and (2) to assess which
components of the BODE index are associated with these psychological aspects of COPD.
Methods: COPD was classified according to the GOLD stages based on FEV in 122 stable1%predicted
patients with COPD. An additional four stage classification was constructed based on the quartiles
of the BODE index. The hospital anxiety and depression scale was used to assess anxious and
depressive symptoms.
Results: The overall prevalence of anxious and depressive symptoms was 49% and 52%,
respectively. The prevalence of anxious symptoms increased with increasing BODE stages but not
with increasing GOLD stages. The prevalence of depressive symptoms increased with both
increasing GOLD and BODE stages. The BODE index was superior to FEV for explaining1%predicted
anxious and depressive symptoms. Anxious symptoms were explained by dyspnoea. Depressive
symptoms were explained by both dyspnoea and reduced exercise capacity.
Conclusion: The BODE index is superior to the GOLD classification for explaining anxious and
depressive symptoms in COPD patients. These psychological consequences of the disease may play
a role in future classification systems of COPD.
Background morbidity. Treatment goals in COPD are prevention or
Chronic obstructive pulmonary disease (COPD) is a pro- deceleration of progression and increasing patients' qual-
gressive disorder leading to substantial mortality and ity of life [1]. Apart from physical impairment, patients
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with COPD carry substantial mental burden related to Inclusion and exclusion criteria
their disease and its symptoms. Patients frequently suffer Inclusion criteria were (1) COPD diagnosed according to
from anxiety [2-7] and depression [2-10]. Both anxiety the GOLD consensus [25], (2) Stable conditions i.e.
and depression are risk factors for rehospitalisation in absence of exacerbation (patients could be recruited dur-
COPD [6,7]. Co-morbid depression is associated with ing exacerbations but were investigated after a stable
longer hospitalisation stay and poorer survival [9]. Analo- period of at least 3 months), (3) ability to perform a six
gously to congestive heart failure [11-14], coronary artery minute walking test.
disease [15] and diabetes [16] psychological disorders are
becoming increasingly recognized as important outcome- Exclusion criteria were (1) absence of informed consent,
modifying co-morbidities in COPD. Irrespective of (2) insufficient knowledge of German for completing the
somatic diseases, anxiety and depression themselves are questionnaires, (3) unstable coronary artery disease, (4)
risk factors of increased mortality [17-19]. While the history of congestive heart failure, (5) significant pulmo-
mechanisms of these associations are largely unknown, nary disease other than COPD (e.g. asthma or lung can-
they are susceptible to therapeutic intervention; treating cer), (6) significant neurological disease.
major depression in older patients decreases their mortal-
ity [20,21]. All together 228 patients were screened, of which 151
were eligible according to the inclusion and exclusion cri-
Whether the severity of the lung function impairment is teria. Of those 122 patients agreed to participate in the
related to anxiety and depression in patients with COPD study (response rate 81%).
has been subject of research. In most studies FEV was a1
bad predictor of anxiety and depression [2,7,9,10,22]. Classification of COPD
Spirometry was performed according to the ATS/ERS rec-
On the other hand, the presence of respiratory symptoms ommendations [27] using a standard PFT unit (Sensor-
causes substantial anxiety and depression [23]. Dyspnoea Medics Vmax 22, Viasys Healthcare). Blood gases were
has been shown to correlate with anxiety and depression determined in arterialised ear lobe samples using the AVL
in patients with COPD [22]. The BODE index (body mass Compact 3 Blood Gas Analyzer (Roche Diagnostics, Graz,
index, airflow obstruction, dyspnoea, and exercise capac- Austria). COPD was classified according to the guidelines
ity) is a multistage functional scoring system for COPD of the Global Initiative for Obstructive Lung Disease
comprising an assessment of symptoms, a surrogate of the (GOLD).
nutritional state, and exercise capacity together with the
spirometric measure of airflow (FEV ) [24]. This multidi- Additionally the BODE index was calculated for classifica-1
mensional grading system was shown to be superior over tion of COPD. The score comprises body mass index
the FEV -based GOLD classification [25] for predicting (BMI), post-bronchodilator FEV , grade of dysp-1 1%predicted
hospitalization and the risk of death among patients with noea (measured by the modified Medical Research Coun-
COPD [24,26]. Given the incorporation of the subjective cil dyspnoea scale, MMRC) and the six-minute-walking-
variable 'dyspnoea' and the individual exercise capacity, distance [24]. For calculation of the BODE index, we used
the BODE index should be closer related to the individual the empirical model as previously described [24]: for each
subjective consequences of COPD than lung function threshold value of FEV , distance walked in six1%predicted
minutes, and score on the MMRC dyspnoea scale [28], thealone.
patients received points ranging from 0 (lowest value) to
The aim of this study was twofold. First, to test whether 3 (maximal value). For body mass index the values were 0
the BODE index is superior to the GOLD classification for or 1. The points for each variable were added, so that the
explaining of anxious and depressive symptoms. Second, BODE index ranged from 0 to 10 points in each patient.
to assess which components of the BODE index are asso- The post bronchodilator FEV was used and clas-1%predicted
ciated with these psychological aspects of COPD. sified according to the three stages identified by the Amer-
ican Thoracic Society [29]. The best of two 6-min walk
Patients and methods tests performed at least 30-min apart [30] was taken as a
Patient recruitment surrogate of exercise capacity and was used for scoring.
This was a prospective cross-sectional study performed at Variables and point values used for the computation of
the Department of Respiratory and Critical Care Medicine the BODE index are shown in table 1. Finally after obtain-
of a primary hospital in Vienna between January 2006 and ing the BODE index for all patients, quartiles of the BODE
May 2007. Adult ( ≥ 18 yr) in- and out-patients of the insti- index were used to construct four severity stages [24,26]:
tution were screened for the study. The study was
approved by the Institutional ethics committee and writ- BODE stage I = BODE index 0 – 2;
ten informed consent was obtained from all patients.
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Table 1: Variables and Point Values Used for the Computation of Statistics
the Body-Mass Index, Degree of Airflow Obstruction and Data on interval scales were described by means± stand-
Dyspnoea, and Exercise Capacity (BODE) Index according to st toard deviations, data on ordinal scales by medians (1[24].*
rd 3 quartiles). Normality was assessed using normal plots
Variable Points on the BODE Index and data were transformed as needed. Differences
between means were tested with Student's t-test and
01 23 reported with 95% confidence intervals (95%CI). Differ-
ences of the anxiety score and the depression score
FEV † ≥ 65 50–64 36–49 ≤ 351%predicted between the different stages of disease se