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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 12  |  Issue : 1  |  Page : 18-23

To study the correlation of chronic obstructive pulmonary disease (COPD) assessment test, clinical COPD questionnaire, and BODE index in patients of stable COPD


Department of Pulmonary Medicine, Government Medical College, Amritsar, Punjab, India

Date of Submission22-Nov-2021
Date of Acceptance21-Feb-2022
Date of Web Publication18-Apr-2022

Correspondence Address:
Dr. Amanpreet Kaur
Department of Pulmonary Medicine, Government Medical College, Circular Road, Amritsar, Punjab 143001
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ajoim.ajoim_21_21

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  Abstract 

Background: Chronic obstructive pulmonary disease (COPD) assessment has emerged as one of the most important parts of COPD treatment. Therefore, a thorough assessment of symptoms is necessary rather than just a measure of dyspnea. Objective: The aim of this study is to assess the disease severity and health status in stable patients of COPD using COPD assessment test (CAT), clinical COPD questionnaire (CCQ) scores, and BODE index and to correlate these indices. Materials and Methods: The study included 100 stable patients suffering from COPD attending outpatient department subjected to CAT, CCQ, and BODE index. Results: CAT and CCQ score correlated significantly (r = 0.52, P < 0.001) and both with the BODE index (r = 0.68; CAT and r = 0.64; CCQ, P < 0.001). COPD severity status and BODE component and forced expiratory volume 1% (FEV1%)-predicted values correlated significantly with individual scores (r = −0.24, CAT; r = −0.41, CCQ; r = −0.72, BODE). Conclusion: An evident negative correlation of FEV1% predicted by CAT and CCQ among study subjects proved both questionnaires as sensitive, simple, and reliable tools not only for early recognition and assessing health status in COPD patients but also for planning appropriate treatment. The BODE index is more objective to assess the disease severity in COPD.

Keywords: Chronic obstructive pulmonary disease, chronic obstructive pulmonary disease assessment test, clinical chronic obstructive pulmonary disease questionnaire, Modified Medical Research Council


How to cite this article:
Kaur A, Goyal A, Pandhi N. To study the correlation of chronic obstructive pulmonary disease (COPD) assessment test, clinical COPD questionnaire, and BODE index in patients of stable COPD. Assam J Intern Med 2022;12:18-23

How to cite this URL:
Kaur A, Goyal A, Pandhi N. To study the correlation of chronic obstructive pulmonary disease (COPD) assessment test, clinical COPD questionnaire, and BODE index in patients of stable COPD. Assam J Intern Med [serial online] 2022 [cited 2022 May 21];12:18-23. Available from: http://www.ajimedicine.com/text.asp?2022/12/1/18/343429




  Introduction Top


Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide and growing healthcare problem all over the world. It is characterized by persistent respiratory symptoms and progressive and irreversible limitation of airflow, and a major goal of its treatment is to ensure that patients health is optimized. Its management not only includes pharmacotherapy but also includes optimizing symptom control and reducing future risks of exacerbations, mortality, comorbidities, as well as the long-term consequences of COPD.[1] Dyspnea measurements in COPD have been demonstrated to predict general health status[2] and exercise performance after pulmonary rehabilitation (PR).[3] Moreover, categorizing patients with COPD based on their level of dyspnea correlates closely with 5-year survival, more so than staging of disease severity based on lung function alone.[4] Thus, although prevention and treatment of symptoms may not prevent long-term lung function decline, symptom control could provide measurable improvements in other key outcomes. The most efficient way for physicians to assess patients’ symptom severity, daily life activity limitation, and health-related quality of life (QoL) accurately is to use a rapid, reliable, and standardized measure, such as a short patient-centered questionnaire such as COPD assessment test (CAT), the clinical COPD questionnaire (CCQ), and the BODE index. We, in this study, have used CAT and CCQ scores and correlated these with BODE index in stable COPD patients for the assessment of their clinical status and disease severity.


  Materials and Methods Top


Study design

This study was carried out in the Department of Pulmonary Medicine, Government Medical College, Amritsar, Punjab, India. This was an observational cross-sectional study including 100 stable patients suffering from COPD attending outpatient department. COPD was diagnosed on the basis of past history, physical examination, and spirometric data, according to the GOLD guidelines and patients were categorized for disease severity using spirometric parameters. The study was conducted after being approved by the Ethics Committee of the Institute and obtaining informed consent from the patients.

Patient selection

Inclusion criteria

  1. One hundred stable patients of COPD, stable being those who were not in exacerbation at the time of enrollment;


  2. Patients consented for the study.


COPD was diagnosed using clinical parameters along with spirometric assessment as per the GOLD guidelines.

Exclusion criteria

  1. Patients not consented for the study;


  2. Patients who were having exacerbation;


  3. Some preexisting non-respiratory illnesses such as severe anemia, cardiac illness, chronic kidney disease, and chronic liver disease were excluded.


  4. Previously diagnosed respiratory entities such as pneumonia, diffuse bronchiectasis, and interstitial lung disease.


CAT consists of 8 items, with scores ranging from 0 to 5 (0 = no impairment, 5 = greatest impairment). An overall score is calculated by simply adding the points of the 8 questions ranging from 0 to 40, with higher scores indicating more severe health status impairment or a poorer control of COPD.

CCQ is a short health status questionnaire with 10 items that are categorized into three domains, namely, symptoms, functional state, and mental state. Score of 1–6 for each of 10 questions added to get a total score of 0–60.

Patients were provided with the questionnaire and explained how to fill them accurately and assisted in its completion whenever needed. Scoring was done at the time of OPD visit.

BODE index: The BODE index includes

  1. Body mass index: Expressing the systemic consequences of COPD (scores 0–1);
  2. Obstruction: forced expiratory volume 1% (FEV1%) that quantifies the degree of pulmonary impairment (scores 0–3);
  3. Dyspnea: modified Medical Research Council (mMRC) Dyspnea Scale that captures patients perception of symptoms (scores 0–3);
  4. Exercise: 6-min walk test (scores 0–3).


The BODE index results in a score of 0–10.

Statistical analysis

The findings of CAT, CCQ, and BODE index were collected. The correlation between quantitative variables was performed using Pearson’s correlation coefficient. P < 0.05 was considered statistically significant. The data were compiled and statistically analyzed to know the correlation of various COPD indices.


  Results Top


The present study was conducted in the Department of Pulmonary Medicine in Government Medical College, Amritsar, Punjab, India, to study the correlation among CAT, CCQ, and BODE index in patients of stable COPD.

One hundred patients diagnosed as a case of COPD and not in exacerbation at the time of enrollment were included in the study.

Out of 100 patients, the maximum number of patients was between the age of 51 and 60 years (39%), patients of age <40 were 6 (6%), 22 patients (22%) were 41–50 years old, 23 (23%) were 61–70 years old, and 10 (10%) were >70 years old. As age is a risk factor for COPD, most of the patients were more than 50 years old. The mean age was 57.77 ± 10.35.

Most of the patients were males (69%) and the remaining were females (31%).

Most of the patients had a significant history of exposure to either tobacco smoke or other indoor or outdoor air pollution as a risk factor for COPD. More than 50 patients had a history of smoking, 32% had a history of biomass fuel exposure for a significant time in their life, and 22% had a history of pulmonary tuberculosis earlier in their life. There is growing evidence that indoor biomass exposure to modern and traditional fuels used during cooking may predispose women to develop COPD in many developing countries.[5],[6] Past history of tuberculosis has also emerged as a cause for airway obstruction causing COPD. A study was done in 100 fully treated pulmonary tuberculosis patients in a tertiary care teaching hospital in India. Brashier et al.[7] reported a 46% prevalence of airflow obstruction and the prevalence increased with the duration after treatment completion. In smokers, 7.6% have pack-years of smoking of <20, 25% have pack-years of 21–40, 63.4% have in the range of 41–60, and 3.8% have 61–80.

All the patients were having complaints of breathlessness, 66% were having cough along with breathlessness, fever was presenting complaint in only 20% of the cases, whereas chest tightness was a complaint in 55% of the cases. According to the Gold guidelines 2020, chronic and progressive dyspnea is the most characteristic complaint of COPD, and cough with sputum was the next common complaint among patients of COPD.

Most of the patients, 57% in 100 patients, have symptom duration of 1–2 years. About 17% have symptom duration of 5–6 years, and 15% have symptoms for more than 10 years. This shows the chronicity of the disease as symptoms in COPD vary from day to day and progress and may precede the development of airflow limitation for several years.

On spirometry [Table 1], most of the patients (86%) had FEV1% less than 50%, including 44% of the patients who had FEV1% of less than 30%. According to GOLD staging of airflow obstruction, all the patients had moderate-to-severe obstruction. Out of 100 patients, moderate obstruction was present in 14%; 42% were having severe obstruction and 44% were having very severe obstruction. Mean FEV1% was 34.62 ± 16.67.
Table 1: Spirometry

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COPD assessment done with CAT score [Table 2] showed that most of the patients had CAT score in the range of 21–30, 37% had score in the range of 11–20, and 20% had score in the range of 31–40. These ranges represent a range of impacts, with the range 31–40 showing very high impact, 21–30 shows high impact, 11–20 shows medium impact, and 0–10 shows low impact. Mean CAT score was 22.95 ± 6.70.
Table 2: COPD assessment test

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Clinical COPD questionnaire [Table 3]: The CCQ results can be interpreted as: acceptable (CCQ <1); acceptable for moderate disease (CCQ 1–2); instable-severe limited (CCQ 2–3); and very instable-very severe limited (CCQ>3).[8] Out of 100 patients, 22% have CCQ score in the range of 1.1–2.0 (moderate disease), 38% have score of 2.1–3.0 (instable severe limited disease), 15% have score of 3.1–4.0, 24% have 4.1–5.0, and only 1% of patients have a score of 5.1–6. Therefore, 40% have a score more than 3 (very instable-very severe limited). The mean CCQ score was 2.98 ± 1.19.
Table 3: Clinical COPD questionnaire

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The BODE index [Table 4] was calculated as the degree of airflow obstruction measured by FEV1%, dyspnea by the mMRC Dyspnea scale, and exercise capacity by the distances of the six-minute-walk test (6-MWD). For each value of FEV1%, mMRC Dyspnea scale, and 6-MWD, points range from 0 to 3 and for body mass index, the point was either 0 or 1. The points for each BODE component were added, so that the BODE index ranged from 0 to 10 points for each patient. The BODE score was further quartilized as follows: quartile 1 (a score of 0–2 points), quartile 2 (a score of 3–4 points), quartile 3 (a score of 5–6 points), and quartile 4 (a score of 7–10 points).[9] The BODE Index score was 1–2 in 17% of the patients, 20% were having 3–4, 22% have scores of 5 and 6, and 41% have scores of 7–10. The mean BODE was 5.66 ± 2.64.
Table 4: BODE index

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Correlation calculation

CCQ and CAT



Correlation =0.7361

R² = 0.542

P-value <0.001

A statistically significant positive correlation was found when COPD assessment score was correlated with the CCQ.

BODE and CCQ



Correlation = 0.68413

R² = 0.468

P-value≤0.001

A statistically significant positive correlation was obtained when CCQ (x-axis) and BODE index (y-axis) correlated with each other.

BODE and CAT



Correlation: 0.684716

R² = 0.468

P-value ≤ 0.001

A statistically significant positive correlation was found on correlating BODE index (y-axis) and CAT score (x-axis).

PFT [FEV1%] and CAT



Correlation: -0.24765

R² = 0.061

P-value≤0.005

A statistically significant negative correlation was found when CAT score (y-axis) was correlated with FEV1% (x-axis).

FEV1% and CCQ



Correlation: -0.4165

R² = 0.173

P-value≤0.005

A statistically significant negative correlation was found between FEV1% (x-axis) and CCQ (y-axis).

FEV1% and BODE



Correlation: -0.721

R² = 0.519

P-value ≤0.001

A statistically significant negative correlation was obtained between FEV1% (x-axis) and BODE index (y-axis).


  Results Top


As shown in [Table 5], a statistically significant positive correlation was found (r = 0.7361, r2 = 0.542) with a P-value <0.001 between CAT and CCQ scores. There was a positive correlation between CCQ and BODE scores in this study group (CCQ vs. BODE, r = 0.6841 [P < 0.001]). There is an evident positive correlation between CAT scores and BODE index scores (r = 0.6847) with a P-value < 0.001, as shown in graphs.
Table 5: Correlation results

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There is an evident negative correlation between CAT scores and the FEV1% predicted among study subjects. When CCQ score was compared with the FEV1% predicted in the study group, there was an apparent negative correlation (r = -0.4165, r2 = 0.173), with a significant P < 0.001. When the BODE index score of study sample was compared with FEV1% predicted, there was an evident negative correlation (r = -0.721, r2 = 0.519) with a significant P < 0.001.


  Discussion Top


We found a statistically significant positive correlation (r = 0.7361, r2 = 0.542) with a P-value less than 0.001 between CAT and CCQ scores.

There was a positive correlation between CCQ and BODE scores in this study group (CCQ vs. BODE, r = 0.6841 [P < 0.001]). This was consistent with the prospective cross-sectional study conducted by Liu et al.[10] to know about the relationship between CCQ score and BODE index. They found that the total CCQ score correlated well with BODE score (P < 0.001) and GOLD staging (P < 0.001).

There is an evident positive correlation between CAT scores and BODE index scores (r = 0.6847) with a P-value less than 0.001, as shown in graphs. In a retrospective study including 50 patients conducted by Ladeira et al.,[11] CAT score and its impact on a patient’s daily life (assessed with mMRC, 6MWT) were correlated with BODE index score: r = 0.475, P < 0.01 and r = 0.377, P = 0.004 and BODE index class: r = 0.357, P = 0.011 and r = 0.326, P = 0.021.

There is an evident negative correlation between CAT scores and the FEV1% predicted among study subjects, which proved that CAT questionnaire is a sensitive, simple, and reliable tool for early recognition and assessing health status in COPD patients. CAT score can also be used in the clinical settings in which spirometry is not readily available. It is patient-friendly and easy to calculate and hence can be used repeatedly for health monitoring in technology-deprived point of care health facilities. Similar results were seen by Ghobadi et al.,[12] who conducted a study in 105 patients with stable COPD to determine the impact of COPD on health status and to assess the relationship between CAT score and PFT in COPD patients. The mean CAT score was 22.95 ± 6.7 SD. There was a significant association between the FEV1% predicted and total CAT score (r = −0.2476, r2 =0.061) with a P < 0.001.

When CCQ score was compared with the FEV1% predicted in the study group, there was an evident negative correlation (r = -0.4165, r2 = 0.173), with a significant P < 0.001. Analyzing the assessment of CCQ score regarding COPD disease severity and QoL, the above significant statistical findings suggested that as the severity of disease in patients increases, thereby leading to fall in FEV1% predicted, the CCQ scores will continue rising. This also suggests that the severity status of COPD patients can also be classified with the assessment of individual CCQ scores. Kon et al.[13] conducted a similar study to assess the responsiveness of the CCQ to PR in 261 COPD patients. They concluded that the CCQ, St. George Respiratory Questionnaire, Chronic Respiratory Questionnaire, and CAT all significantly improved with PR with an effect size of −0.39, −0.33, 0.62, and −0.25, respectively, and advocated the use of CCQ as a practical alternative to more time-consuming measures of health-related QoL.

When the BODE index score of the study sample was compared with FeV1% predicted, there was an evident negative correlation (r = -0.721, r2 = 0.519) with a significant P < 0.001. Hence, we can also assess the disease severity of COPD by assessing BODE index score value of an individual. Celli et al.[9] also concluded that the BODE index, a simple multidimensional grading system including objective (FEV1%) as well as functional assessment (mMRC, 6-MWD), is a better tool than using FEV1% alone, at predicting the risk of death from any cause and respiratory causes among patients with COPD. Patients with higher BODE scores were at higher risk for death; the hazard ratio for death from any cause per one-point increase in the BODE score was 1.34 (95% confidence interval, 1.26–1.42; P < 0.001).

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Zhou Y, Zou Y, Li X, Chen S, Zhao Z, He F, et al. Lung function and incidence of chronic obstructive pulmonary disease after improved cooking fuels and kitchen ventilation: A 9-year prospective cohort study. PLoS Med 2014;11:e1001621.  Back to cited text no. 5
    
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Sana A, Somda SMA, Meda N, Bouland C Chronic obstructive pulmonary disease associated with biomass fuel use in women: A systematic review and meta-analysis. BMJ Open Respir Res 2018;5:e000246.  Back to cited text no. 6
    
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Brashier B, Gangavane S, Valsa S, Gaikwad SN, Ghorpade SV, Mandrekar S, et al. Almost Half the Patients Treated for Pulmonary Tuberculosis Show Evidence of Obstructive Airways Disease. Stockholm, Sweden: European Respiratory Society Annual Congress; September 15–18, 2007.  Back to cited text no. 7
    
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Ladeira I, Gomes T, Castro A, Ribeiro C, Guimarães M, Taveira N The overall impact of COPD (CAT) and BODE index on COPD male patients: Correlation? Rev Port Pneumol (2006) 2015;21:11-5.  Back to cited text no. 11
    
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Ghobadi H, Ahari SS, Kameli A, Lari SM The relationship between COPD assessment test (CAT) scores and severity of airflow obstruction in stable COPD patients. TANAFFOS 2012;11:22-6.  Back to cited text no. 12
    
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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