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Clinical Investigations: COPD |

A Comparison of the Level of Dyspnea vs Disease Severity in Indicating the Health-Related Quality of Life of Patients With COPD* FREE TO VIEW

Takashi Hajiro, MD; Koichi Nishimura, MD; Mitsuhiro Tsukino, MD; Akihiko Ikeda, MD; Toru Oga, MD; Takateru Izumi, MD, FCCP
Author and Funding Information

*From the Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Correspondence to: Takashi Hajiro, MD, Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 53 Kawahara, Shogoin, Sakyo, Kyoto, 606-8507, Japan; e-mail: hajiro@kuhp.kyoto-u.ac.jp



Chest. 1999;116(6):1632-1637. doi:10.1378/chest.116.6.1632
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Published online

Study objectives: To compare categorizations of the level of dyspnea with the staging of disease severity as defined by the FEV1 in representing how the health-related quality of life (HRQOL) is distributed in patients with COPD.

Design: Cross-sectional study.

Setting: Outpatient clinic at the respiratory department of a university hospital.

Patients: A total of 194 consecutive male patients with stable, mild-to-severe COPD.

Measurements: The score distributions for the components of the St. George’s respiratory questionnaire (SGRQ) were used as disease-specific HRQOL measures, and the scores from the Medical Outcomes Study Short Form 36-item questionnaire (SF-36) were used as generic HRQOL measures. These scores were stratified according to the level of dyspnea, as defined by the Medical Research Council (MRC) dyspnea scale, and the stage of disease severity, as defined by the American Thoracic Society (ATS). Differences in the HRQOL scores among the subgroups were compared by an analysis of variance (ANOVA). Multiple pairwise comparisons were made with Fisher’s least significant difference (LSD) method, with the overall α-level set at 0.05.

Results: In those groups classified according to the level of dyspnea, significant differences were observed for the scores on the SGRQ and SF-36 (ANOVA, p < 0.05). The scores for activity and impact, and the total scores of the SGRQ and all scales, except for bodily pain and general health on the SF-36, were significantly worse for patients with severe dyspnea (MRC scale grades, 3, 4, and 5, respectively) than for those with moderate dyspnea (MRC grade level, 2; Fisher’s LSD method, p < 0.05). Significant differences were recognized among the different stages of disease severity with respect to the scores from all scales of the SF-36, except for bodily pain, and all scores from the SGRQ (ANOVA, p < 0.05). However, differences in the scores on the SGRQ and SF-36 between patients with ATS stage II disease (FEV1, 35 to 49% predicted) and stage III disease (FEV1, < 35% predicted) were not statistically significant.

Conclusions: Using the SGRQ and SF-36, the HRQOL of patients with COPD was more clearly separated by the level of dyspnea than by the ATS disease staging. In addition to the ATS disease staging, categorizations based on the level of dyspnea may be useful to clinicians in terms of the HRQOL of COPD patients.

Figures in this Article

The approach to COPD would be facilitated by a staging system that could categorize a heterogeneous population of patients.1 Generally, COPD is categorized by the degree of airflow limitation; the percentage of the predicted FEV1 is used mainly because the FEV1 is highly correlated with morbidity and mortality. The American Thoracic Society (ATS),,1the British Thoracic Society,2and the European Respiratory Society3 each have introduced a staging system with different cut-off points for FEV1 related to severity of disease. For example, the ATS guidelines proposed the following categorization for COPD: stage I, FEV1 50 to 79% of the predicted value; stage II, FEV1 35 to 49% of the predicted value; and stage III, FEV1< 35% of the predicted value.

From the point of view of patients, dyspnea is one of the major symptoms that impacts their quality of daily life.4 However, dyspnea varies considerably for the same degree of airflow limitation.5 From a clinical point of view, patients with COPD can be categorized into subgroups based on their level of dyspnea. For example, one could categorize patients into three levels, such as the following: no or little dyspnea, dyspnea on exertion, and dyspnea on any exertion or at rest.2 In other words, categorizing patients on the basis of their level of dyspnea may generate another classification of COPD. For example, there has been one report in which categorizations based on the level of dyspnea were introduced and used for evaluating the heterogeneity of the effects of pulmonary rehabilitation in patients with COPD.6

The health-related quality of life (HRQOL) is being recognized as an important outcome when evaluating patients with COPD.78 In terms of the relationship between the HRQOL and the disease staging system, Ferrer and colleagues9 demonstrated that those patients in more severe disease stages, as defined by the ATS guidelines, presented with a poorer HRQOL. They also pointed out that the HRQOL varied greatly within each stage of disease severity.

Although the role of HRQOL instruments has not been established in daily clinical practice, we have two clinically applicable methods to assess patients with COPD: the FEV1, as an objective index; and the level of dyspnea, as a subjective index. Categorizations based on the these two indexes are easily evaluated in a clinical setting. In the present study, we compared categorizations of the level of dyspnea with the staging of disease severity as defined by the ATS in order to determine how the HRQOL is distributed among patients with stable mild-to-severe COPD. The severity of the dyspnea was evaluated by the modified Medical Research Council (MRC) dyspnea scale.10The HRQOL was assessed with the St. George’s respiratory questionnaire (SGRQ) as a disease-specific measure,11and with the Medical Outcomes Study Short Form 36-item questionnaire (SF-36) as a generic measure.12

Patients with stable COPD, as defined by the ATS,1 were recruited from our outpatient clinic from October 1996 to August 1998. All of the patients had at least 6 months of outpatient management before entry into the study to avoid substantial changes in subjective parameters brought about by any new medical interventions.13 The entry criteria for the study were the following: (1) a maximum FEV1/vital capacity (VC) ratio of < 0.7 and an FEV1 < 80% of the predicted value for all measurements made over the prior 6 months; (2) a smoking history of > 20 pack-years; (3) no history suggestive of asthma; (4) no exacerbations of the airflow limitation over the preceding 6 weeks; and (5) no changes in treatment regimen over the preceding 4 weeks. All of the patients had been advised to stop smoking and to increase their physical exercise, and they also received education regarding the proper use of the inhalation devices. All eligible patients finished the following examinations on the same day: pulmonary function tests, assessments of their dyspnea, and assessments of their HRQOL. Verbal informed consent was obtained from all patients.

The FEV1 and VC were assessed after the inhalation of bronchodilators was withheld for at least 12 h. The postbronchodilator FEV1 also was assessed at 15 min and 60 min after the inhalation of salbutamol, 400 μg, plus ipratropium bromide, 80 μg, using a metered-dose inhaler with a spacer device (InspirEase; Schering-Plough K. K.; Osaka, Japan, Madison, NJ). All spirometric flow-volume curves were recorded according to the method described in the ATS 1994 update.14The predicted values for the FEV1 and VC were calculated based on the proposal of the Japan Society of Chest Diseases.15

The level of dyspnea can be categorized roughly into three groups: no or little dyspnea (“mild” dyspnea); dyspnea on exertion (“moderate” dyspnea); and dyspnea on any exertion or at rest (“severe” dyspnea).2 These categorizations came about as an attempt to match the categorization to the disease staging of the ATS. In the present study, dyspnea was evaluated by the Japanese version of the MRC dyspnea scale, which consists of a 5-point scale.10,16 We defined mild dyspnea as patients with MRC scale 1, moderate dyspnea as patients with MRC scale 2, and severe dyspnea as patients with MRC scales 3 to 5.

The HRQOL was assessed with the Japanese versions of the SGRQ, as a disease-specific measure, and the SF-36, as a generic measure. The Japanese versions of the SGRQ and the SF-36 previously have been validated.4,17 The SGRQ has the following three components: symptoms, which reflects the respiratory symptoms; activity, which reflects the activities that evoke or are limited by dyspnea; and impact, a measure of the overall disturbance. The total score of the SGRQ was also calculated. The scores for the SGRQ were calculated following the procedures outlined by its developers. The SGRQ scores ranged from 0 to 100, with 0 indicating no impairment in the quality of life. The SF-36 contains 36 items that are aggregated into the following eight scales: functioning, physical and social; role, physical and emotional; mental health; vitality; bodily pain; and general health perception (Table 1 ). Those scores were then transformed into a score from 0 to 100, with 0 and 100 assigned to the lowest and highest possible scores, respectively. A higher score on the SF-36 indicates a better quality of life. The SGRQ and SF-36 were self-administered in booklet form. One of the authors (M.T.) checked the answers in front of the patients in order to avoid possible missing items.

The distribution of the HRQOL scores was represented by box plots, since box plots are the most appropriate means of expressing either normally or non-normally distributed data.18 The boxes show the first to third quartile, the horizontal line represents the median, and the vertical bars indicate the 10th to 90th percentiles (Fig 1 ). Differences in the HRQOL scores among the subgroups were compared by analysis of variance, and statistical significance was established at p < 0.05. Multiple pairwise comparisons were made with Fisher’s least significant difference (LSD) method, with the overall α-level set at 0.05.

A total of 194 consecutive male patients were evaluated. The patient characteristics and scores on the SGRQ and SF-36 are shown in Table 1. Fifty-seven patients (29%) had stage I COPD, 62 patients (32%) had stage II COPD, and 75 patients (39%) had stage III COPD. With respect to the level of dyspnea severity, 59 patients (30%) had mild dyspnea (MRC grade 1), 82 patients (42%) had moderate dyspnea (MRC grade 2), and 53 patients (27%) had severe dyspnea (MRC grades 3, 4, and 5). Forty-six patients were current smokers. One hundred eighty-eight patients (97%) were treated with the inhalation of bothβ -agonists and anticholinergic agents. In addition to the inhalation agents, oral theophylline (300 to 800 mg/d) was administered to 21 patients (11%), and oral prednisolone (2.5 to 10 mg/d) was administered to 9 patients (5%). Ninety-three patients (48%) also were treated with high doses (1,600 to 2,400 μg/d) of inhaled beclomethasone dipropionate. Five patients received no medication, and seven patients were managed with long-term oxygen therapy.

The impairments of the disease-specific quality of life increased as the level of dyspnea increased, as shown in Figure 2. Of the groups classified by their level of dyspnea, significant differences were observed for the scores of three components and the total score on the SGRQ (one-way analysis of variance, p < 0.05). The scores for activity and impact, and for the total score were significantly higher for patients with severe dyspnea than for patients with moderate dyspnea (Fisher’s LSD method, p < 0.05; Fig 2 ). For symptoms, the scores of moderately dyspneic patients were significantly higher than those of mildly dyspneic patients (Fisher’s LSD method, p < 0.05; Fig 2) but were not significantly different from those of severely dyspneic patients.

The same tendency was recognized in the score distributions on the SF-36 with respect to the subgroups based on the level of dyspnea (Fig 3 ). The scores on all scales of the SF-36 except for mental health and bodily pain were significantly lower in patients with moderate and severe dyspnea than in patients with mild dyspnea, with an overallα -level of 0.05 (Fig 3). For scales such as physical function, social function, roles physical and emotional, mental health, and vitality, the scores of patients with severe dyspnea were significantly worse than those of patients with moderate dyspnea (Fisher’s LSD method, p < 0.05; Fig 3).

On the other hand, the health status was not clearly separated among disease stages using the FEV1. Although significant differences were recognized among the groups based on disease severity, none of the scores on any of the three components or the total score on the SGRQ showed any significant differences between stage II and stage III patients (Fig 4 ). With respect to the SF-36, significant differences were recognized between the groups based on the disease severity on the scores of all scales except for bodily pain (Fig 5 ). No significant differences were noted on the scores of any scales between stage II and stage III patients.

We found that the HRQOL of patients with COPD ranging from mild to severe was more clearly separated using the level of dyspnea rather than the staging of the disease severity as defined by the ATS. In addition to the ATS disease staging, categorizations based on the level of dyspnea may be useful to clinicians in terms of the HRQOL of COPD patients.

Even though it is a subjective respiratory sensation, dyspnea can be quantified using an appropriate instrument in a general practice setting.19 We have arbitrarily categorized the MRC 5-grade scale into three levels in an attempt to match it to the ATS disease staging scale. We demonstrated that the score distributions on both the generic and disease-specific HRQOL instruments differed significantly between patient groups based on different levels of dyspnea. These findings may justify our arbitrary categorization on the basis of the level of dyspnea, suggesting that dyspnea grades may give a better estimate of the HRQOL in patients with COPD than disease severity alone. Furthermore, the present categorization based on the level of dyspnea can be performed easily in the clinical setting. A few minutes may be enough to ask patients how their dyspnea affects their daily life by applying the MRC scale, which is short and simple.10 The same information can be obtained while taking the patient’s history, even without applying the MRC scale. Categorizing patients with COPD in accordance with their level of dyspnea may give more insight into the heterogeneity of COPD, which would otherwise be overlooked by categorizations based on the severity of the disease. When HRQOL is one of the primary outcomes in a clinical trial, categorizing the patients based on their level of dyspnea may help explain the changes or responses in the HRQOL.

In general, dyspnea is one of the main determinants of the disease-specific HRQOL, and has moderate-to-strong correlations with impairments in the HRQOL of patients with COPD.4,11,20 With respect to the relationships between the dyspnea grades and generic measures, Mahler and Mackowiak21 showed that all scales on the SF-36, except for role-emotional and mental health, had significant correlations with another clinical dyspnea rating, the baseline dyspnea index.21 The Nottingham Health Profile (NHP), a representative generic measure, was used in a study by Ferrer and colleagues.9 They showed that the total score on the NHP had a moderate correlation to the MRC scale, although specific scores on each dimension of the NHP were not described.

The HRQOL scores on the SGRQ and SF-36 were not significantly different between patients with stage II and stage III COPD. The score distributions on both the SGRQ and SF-36 showed that a considerable number of stage II and stage III patients presented with overlapping scores. Our findings suggest that the staging of disease severity by the ATS is less discriminating than categorization based on the level of dyspnea with respect to the HRQOL. The reasons for this finding may be that HRQOL measures did not correlate well with the severity of airflow limitation,2122 and that the HRQOL varied greatly among patients, especially those with moderate to severe airflow limitation. For example, the symptom score would have been expected to be different between stage II and stage III patients. However, the lack of a relationship in this component in stage II and stage III patients may be due to the substantial variability in their presenting symptoms. Our finding stands in contrast to the report by Ferrer and colleagues,9 who reported that the SGRQ showed a worse HRQOL with increasing stages of COPD and that increasing disease severity as defined by the ATS guidelines reflected a poorer score on the NHP. However, the score distributions between the groups and the scores for each dimension on the NHP were not presented in their report. Further studies may be required to clarify the relationship between the ATS staging system and the HRQOL, since only the report by Ferrer and colleagues9 is available on this issue.

In the present study, the scores on the SF-36 were generally higher than in the previous reports from other countries. For example, the mean score for physical functioning was 74.6 in our population, whereas Mahler and Mackowiak21 reported a score of 43.6 in patients with a mean FEV1 of 1.32 L, and Jones and Bosh,23 reported a score of 46 in patients with a mean FEV1 of 1.3 L. This might be related to the fact that our patients had been receiving adequate treatment for > 6 months, and that only stable patients at our outpatient clinic were enrolled in this study. However, some cultural differences in responding to the questions in this scale should be considered. Second, significant ceiling and floor effects were recognized, especially on scales such as social functioning, role-physical, role-emotional, and bodily pain. These scales have fewer than four items and 11 levels in each scale,,12 and this may bring less discriminatory power to the SF-36 when evaluating the HRQOL of patients with stable COPD.

Although categorizing COPD may facilitate the evaluation of patients by clinicians, the precise boundaries of any categorization are inevitably arbitrary. Three different cut-off points for the percentage of the predicted FEV1 have been proposed by the ATS,1the British Thoracic Society,2and the European Respiratory Society.3 In addition, the score distributions of HRQOL measures may differ among groups once a different classification based on the disease severity is applied to patients with COPD. How these different categorizations describe impairments in the HRQOL remains to be analyzed.

We should mention some of the limitations of the present study. Our study included only men, since we experienced difficulty in recruiting sufficient numbers of women patients with COPD. Therefore, generalizations of our results to women with COPD may be unwarranted. Second, since we recruited only stable patients from the outpatient clinic, the study sample may not be representative of patients with severe COPD who are incapable of making regular visits. Third, the HRQOL was evaluated by the SGRQ, a representative, disease-specific questionnaire. Using another disease-specific instrument may have provided different results, since the SGRQ may not be able to discriminate among impairments in the HRQOL of patients with more severe disease.24

In conclusion, categorizing patients with COPD based on their level of dyspnea was more discriminating than disease staging with the ATS criteria with respect to HRQOL. Categorizations based on the level of dyspnea, as well as airflow limitation, may give a good indication to the clinician of the quality of life of patients with COPD. Further study may be warranted to investigate whether categorization by dyspnea is useful as an index for health-care utilization, prognosis, and application of clinical interventions.

Abbreviations: ATS = American Thoracic Society; HRQOL = health-related quality of life; LSD = least significant difference; MRC = Medical Research Council; NHP = Nottingham Health Profile; SF-36 = Medical Outcomes Study Short Form 36-item questionnaire; SGRQ = St. George’s respiratory questionnaire; VC = vital capacity

This study was supported in part by the Smoking Research Foundation of Japan.

Table Graphic Jump Location
Table 1. Patient Characteristics and HRQOL Scores of 194 Male Patients With COPD
* 

Higher scores indicate a poorer quality of life.

 

Higher scores indicate a better quality of life.

Figure Jump LinkFigure 2. Box and whisker plots representing the score distributions on the components of the SGRQ between groups based on the MRC dyspnea scale. A higher score indicates a poorer quality of life on the SGRQ. * = significant differences in the scores were observed for patients with mild dyspnea; † = significant differences in the scores of those with moderate dyspnea (Fisher’s LSD method, p < 0.05).Grahic Jump Location
Figure Jump LinkFigure 3. Box and whisker plots representing the score distributions on the SF-36 between groups, based on the MRC dyspnea scale. A higher score means a better quality of life on the SF-36.* = significant differences in the scores were observed for patients with mild dyspnea; † = significant differences in the scores of those with moderate dyspnea (Fisher’s LSD method, p < 0.05).Grahic Jump Location
Figure Jump LinkFigure 4. Box and whisker plots representing the score distributions on the components of the SGRQ between groups, based on the staging of disease severity according to the ATS guidelines. A higher score indicates a poorer quality of life on the SGRQ.* = significant differences in the scores were observed for patients with stage I disease severity (Fisher’s LSD method, p < 0.05).Grahic Jump Location
Figure Jump LinkFigure 5. Box and whisker plots representing the score distributions on the SF-36 between groups, based on the staging of disease severity according to the ATS guidelines. A higher score means a better quality of life on the SF-36. * = significant differences in the scores were observed for patients with stage I disease severity (Fisher’s LSD method, p < 0.05).Grahic Jump Location

The authors thank Paul W. Jones, MD (St. George’s Hospital Medical School, London, United Kingdom), for the SGRQ; and Shunichi Fukuhara, MD (The University of Tokyo, Tokyo, Japan), for the SF-36 and for giving us permission to use Japanese versions of each questionnaire. We also appreciate the helpful comments from Hiroshi Koyama, MD. We also thank Ms. Kazuyo Haruna and Ms. Yumiko Tomita for conducting pulmonary function tests. Requests for the Japanese version of the SGRQ should be addressed to Koichi Nishimura, MD.

Celli, BR, Snider, GL, Heffner, J, et al (1995) Standards for the diagnosis and care of patients with chronic obstructive pulmonary disease.Am J Respir Crit Care Med152(suppl),S77-S120
 
Pearson, MG, Bellamy, D, Calverley, PMA, et al BTS guidelines for the management of chronic obstructive pulmonary disease.Thorax1997;52(suppl),S1-S28
 
Siafakas, NM, Vermeire, P, Pride, NB, et al Optimal assessment and management of chronic obstructive pulmonary disease (COPD).Eur Respir J1995;8,1398-1420. [PubMed] [CrossRef]
 
Hajiro, T, Nishimura, K, Tsukino, M, et al Comparison of discriminative properties among disease-specific questionnaires for measuring health-related quality of life in patients with chronic obstructive pulmonary disease.Am J Respir Crit Care Med1998;157,785-790. [PubMed]
 
Wolkove, N, Dajczman, E, Colacone, A, et al The relationship between pulmonary function and dyspnea in obstructive lung disease.Chest1989;96,1247-1251. [PubMed]
 
Wedzicha, JA, Bestall, JC, Garrod, R, et al Randomized controlled trial of pulmonary rehabilitation in severe chronic obstructive pulmonary disease patients, stratified with the MRC dyspnoea scale.Eur Respir J1998;12,363-369. [PubMed]
 
Curtis, JR, Martin, DP, Martin, TR Patient-assessed health outcomes in chronic lung disease: what are they, how do they help us, and where do we go from here?Am J Respir Crit Care Med1997;156,1032-1039. [PubMed]
 
Curtis, JR, Deyo, RA, Hudson, LA Health-related quality of life among patients with chronic obstructive pulmonary disease.Thorax1994;49,162-170. [PubMed]
 
Ferrer, M, Alonso, J, Morera, J, et al Chronic obstructive pulmonary disease stage and health-related quality of life.Ann Intern Med1997;127,1072-1079. [PubMed]
 
Fletcher, CM, Elmes, PC, Wood, CH The significance of respiratory symptoms and the diagnosis of chronic bronchitis in a working population.BMJ1959;1,257-266
 
Jones, PW, Quirk, FH, Baveystock, CM, et al A self-complete measure of health status for chronic airflow limitation: The St. George’s Respiratory Questionnaire.Am Rev Respir Dis1992;145,1321-1327. [PubMed]
 
Ware, JJ, Sherbourne, CD The MOS 36-item short-form health survey (SF-36): I. conceptual framework and item selection.Med Care1992;30,473-483. [PubMed]
 
Harlan, LC, Polk, BF, Cooper, S, et al Effects of labeling and treatment of hypertension on perceived health.Am J Prev Med1986;2,256-265. [PubMed]
 
Medical Section of the American Lung Association. Standardization of spirometry: 1994 update. Am Rev Respir Dis 1994; 152:1107–1136.
 
Japan Society of Chest Diseases. The predicted values of pulmonary function testing in Japanese [in Japanese]. Jpn J Thorac Dis 1993; 31.
 
Hajiro, T, Nishimura, K, Tsukino, M, et al Analysis of clinical methods used to evaluate dyspnea in patients with chronic obstructive pulmonary disease.Am J Respir Crit Care Med1998;158,1185-1189. [PubMed]
 
Fukuhara, S, Bito, S, Green, J, et al Translation, adaptation, and validation of the SF-36 for use in Japan.J Clin Epidemiol1998;51,1037-1044. [PubMed]
 
Simpson, RJ, Johnson, TA, Amara, IA The box-plot: an exploratory analysis graph for biomedical publications.Am Heart J1988;116,1663-1665. [PubMed]
 
Mahler, DA, Guyatt, GH, Jones, PW Clinical measurement of dyspnea. Mahler, DA eds.Dyspnea1997,149-198 Marcel Dekker. New York, NY:
 
Siafakas NM, Schiza S, Xirouhaki N, et al. Is dyspnoea the main determinant of quality of life in the failing lung?: a review. Eur Respir Rev 1997; 7:42, 53–56.
 
Mahler, DA, Mackowiak, JI Evaluation of the short-form 36-item questionnaire to measure health-related quality of life in patients with COPD.Chest1995;107,1585-1589. [PubMed]
 
Prigatano, GP, Wright, EC, Levin, D Quality of life and its predictors in patients with mild hypoxemia and chronic obstructive pulmonary disease.Arch Intern Med1984;144,1613-1619. [PubMed]
 
in association with an international study group. Jones, PW, Bosh, TK Quality of life changes in COPD patients treated with salmeterol.Am J Respir Crit Care Med1997;155,1283-1289. [PubMed]
 
Carone, M, Bertolotti, G, Zotti, AM, et al Development and cross-sectional analysis of a new questionnaire for the quality of life in chronic respiratory failure. Am J Respir Crit Care Med. 1997;;155(suppl) ,.:A721
 

Figures

Figure Jump LinkFigure 2. Box and whisker plots representing the score distributions on the components of the SGRQ between groups based on the MRC dyspnea scale. A higher score indicates a poorer quality of life on the SGRQ. * = significant differences in the scores were observed for patients with mild dyspnea; † = significant differences in the scores of those with moderate dyspnea (Fisher’s LSD method, p < 0.05).Grahic Jump Location
Figure Jump LinkFigure 3. Box and whisker plots representing the score distributions on the SF-36 between groups, based on the MRC dyspnea scale. A higher score means a better quality of life on the SF-36.* = significant differences in the scores were observed for patients with mild dyspnea; † = significant differences in the scores of those with moderate dyspnea (Fisher’s LSD method, p < 0.05).Grahic Jump Location
Figure Jump LinkFigure 4. Box and whisker plots representing the score distributions on the components of the SGRQ between groups, based on the staging of disease severity according to the ATS guidelines. A higher score indicates a poorer quality of life on the SGRQ.* = significant differences in the scores were observed for patients with stage I disease severity (Fisher’s LSD method, p < 0.05).Grahic Jump Location
Figure Jump LinkFigure 5. Box and whisker plots representing the score distributions on the SF-36 between groups, based on the staging of disease severity according to the ATS guidelines. A higher score means a better quality of life on the SF-36. * = significant differences in the scores were observed for patients with stage I disease severity (Fisher’s LSD method, p < 0.05).Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1. Patient Characteristics and HRQOL Scores of 194 Male Patients With COPD
* 

Higher scores indicate a poorer quality of life.

 

Higher scores indicate a better quality of life.

References

Celli, BR, Snider, GL, Heffner, J, et al (1995) Standards for the diagnosis and care of patients with chronic obstructive pulmonary disease.Am J Respir Crit Care Med152(suppl),S77-S120
 
Pearson, MG, Bellamy, D, Calverley, PMA, et al BTS guidelines for the management of chronic obstructive pulmonary disease.Thorax1997;52(suppl),S1-S28
 
Siafakas, NM, Vermeire, P, Pride, NB, et al Optimal assessment and management of chronic obstructive pulmonary disease (COPD).Eur Respir J1995;8,1398-1420. [PubMed] [CrossRef]
 
Hajiro, T, Nishimura, K, Tsukino, M, et al Comparison of discriminative properties among disease-specific questionnaires for measuring health-related quality of life in patients with chronic obstructive pulmonary disease.Am J Respir Crit Care Med1998;157,785-790. [PubMed]
 
Wolkove, N, Dajczman, E, Colacone, A, et al The relationship between pulmonary function and dyspnea in obstructive lung disease.Chest1989;96,1247-1251. [PubMed]
 
Wedzicha, JA, Bestall, JC, Garrod, R, et al Randomized controlled trial of pulmonary rehabilitation in severe chronic obstructive pulmonary disease patients, stratified with the MRC dyspnoea scale.Eur Respir J1998;12,363-369. [PubMed]
 
Curtis, JR, Martin, DP, Martin, TR Patient-assessed health outcomes in chronic lung disease: what are they, how do they help us, and where do we go from here?Am J Respir Crit Care Med1997;156,1032-1039. [PubMed]
 
Curtis, JR, Deyo, RA, Hudson, LA Health-related quality of life among patients with chronic obstructive pulmonary disease.Thorax1994;49,162-170. [PubMed]
 
Ferrer, M, Alonso, J, Morera, J, et al Chronic obstructive pulmonary disease stage and health-related quality of life.Ann Intern Med1997;127,1072-1079. [PubMed]
 
Fletcher, CM, Elmes, PC, Wood, CH The significance of respiratory symptoms and the diagnosis of chronic bronchitis in a working population.BMJ1959;1,257-266
 
Jones, PW, Quirk, FH, Baveystock, CM, et al A self-complete measure of health status for chronic airflow limitation: The St. George’s Respiratory Questionnaire.Am Rev Respir Dis1992;145,1321-1327. [PubMed]
 
Ware, JJ, Sherbourne, CD The MOS 36-item short-form health survey (SF-36): I. conceptual framework and item selection.Med Care1992;30,473-483. [PubMed]
 
Harlan, LC, Polk, BF, Cooper, S, et al Effects of labeling and treatment of hypertension on perceived health.Am J Prev Med1986;2,256-265. [PubMed]
 
Medical Section of the American Lung Association. Standardization of spirometry: 1994 update. Am Rev Respir Dis 1994; 152:1107–1136.
 
Japan Society of Chest Diseases. The predicted values of pulmonary function testing in Japanese [in Japanese]. Jpn J Thorac Dis 1993; 31.
 
Hajiro, T, Nishimura, K, Tsukino, M, et al Analysis of clinical methods used to evaluate dyspnea in patients with chronic obstructive pulmonary disease.Am J Respir Crit Care Med1998;158,1185-1189. [PubMed]
 
Fukuhara, S, Bito, S, Green, J, et al Translation, adaptation, and validation of the SF-36 for use in Japan.J Clin Epidemiol1998;51,1037-1044. [PubMed]
 
Simpson, RJ, Johnson, TA, Amara, IA The box-plot: an exploratory analysis graph for biomedical publications.Am Heart J1988;116,1663-1665. [PubMed]
 
Mahler, DA, Guyatt, GH, Jones, PW Clinical measurement of dyspnea. Mahler, DA eds.Dyspnea1997,149-198 Marcel Dekker. New York, NY:
 
Siafakas NM, Schiza S, Xirouhaki N, et al. Is dyspnoea the main determinant of quality of life in the failing lung?: a review. Eur Respir Rev 1997; 7:42, 53–56.
 
Mahler, DA, Mackowiak, JI Evaluation of the short-form 36-item questionnaire to measure health-related quality of life in patients with COPD.Chest1995;107,1585-1589. [PubMed]
 
Prigatano, GP, Wright, EC, Levin, D Quality of life and its predictors in patients with mild hypoxemia and chronic obstructive pulmonary disease.Arch Intern Med1984;144,1613-1619. [PubMed]
 
in association with an international study group. Jones, PW, Bosh, TK Quality of life changes in COPD patients treated with salmeterol.Am J Respir Crit Care Med1997;155,1283-1289. [PubMed]
 
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