Chinese Medical Journal 2008;121(7):592-596
Effect of dyspnea and clinical variables on the quality of life and functional capacity in patients with chronic obstructive pulmonary disease and congestive heart failure
Hale Karapolat, Sibel Eyigor, Alev Atasever, Mehdi Zoghi, Sanem Nalbantgil, Berrin Durmaz
Hale Karapolat (Ege University Medical Faculty Physical Medicine and Rehabilitation Department, Turkey)
Sibel Eyigor (Ege University Medical Faculty Physical Medicine and Rehabilitation Department, Turkey)
Alev Atasever (Ege University Medical Faculty Pulmonary Medicine Department, Turkey)
Mehdi Zoghi (Ege University Medical Faculty Cardiology Department, Turkey)
Sanem Nalbantgil (Ege University Medical Faculty Cardiology Department, Turkey)
Berrin Durmaz (Ege University Medical Faculty Physical Medicine and Rehabilitation Department, Turkey)Correspondence to:Hale Karapolat,Ege University Medical Faculty Physical Medicine and Rehabilitation Department, 35100 Bornova, Izmir, Turkey (Tel: 902323902406. Fax:902323881953-120. E-mail:email@example.com)
Background Chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF) are two chronic diseases that affect negatively the functional condition and quality of life of patients. We assessed the effect of symptoms and clinical variables on the functional capacity and quality of life in COPD and CHF patients.
Methods The study included 42 COPD and 39 CHF patients. In both patient groups, dyspnea was assessed using Borg scale; functional capacity by shuttle-walk and cardiopulmonary exercise test and quality of life by short form-36 (SF36).
Results No statistically significant difference was found in neither of the two disease groups regarding the dyspnea score, shuttle-walk test and the majority of subgroup scores of SF36 (P>0.05). A statistically significant difference was observed in peak VO2 in favor of COPD group (P<0.05). No significant relationship was established between dyspnea score and forced expiratory volume in one second (FEV1) in COPD patients, and left ventricular ejection fraction (LVEF) in CHF patients (P>0.05). A significant negative correlation was observed between dyspnea score and functional capacity tests in both disease groups (P<0.05). On the other hand, no relationship was found between LVEF and FEV1 and quality of life and functional capacity (P>0.05).
Conclusions It was revealed that symptoms have an impact on functional capacity and quality of life in both disease groups, however, objective indicators of disease severity do not show a similar relationship. Therefore, in addition to the objective data related to the disease, we recommend that symptoms should also be taken into consideration to assess cardiopulmonary rehabilitation program and during following-up.
Chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF) are two chronic and widespread diseases that affect negatively the functional condition and quality of life of patients.1 COPD causes restrictions in daily life activities as a result of reduced pulmonary function, dyspnea, or limitation in exercise tolerance. In CHF, functional disability stemming from dyspnea, fatigue, and reduced exercise capacity leads to similar limitations.1 Dyspnea appears as the main symptom in these diseases and it is stated that the frequency of dyspnea is similar in both diseases.2 While the objective indicator of airflow limitation is forced expiratory volume in one second (FEV1) in COPD, the objective indicator of physical functioning in CHF is the left ventricular ejection fraction (LVEF).1 These two measurements can be considered as indicators of the disease severity. Although underlying causes of these disorders are quite different and may have differential effects on health and quality of life, the process through which disease affects health for COPD and CHF patients may be comparable.
One of the major objectives in the treatment of COPD and CHF patients is the recovery of functional capacity. Providing information regarding quality of life in such chronic diseases does matter in the development of treatment guidelines.3 Most clinicians prefer clinical history to objective methods as far as assessment and monitoring is concerned. However, it is thought that the relationship among symptoms, disease indicators, functional capacity, and quality of life is not so clear with these two diseases and it is very probable to encounter with contraversial results.4 Therefore, the following were aimed to (1) assess in the two groups of disease, the effect of symptoms and disease indicators on the functional capacity and the quality of life, and (2) compare the two diseases with respect to symptoms, functional capacity and quality of life.
Subjects and study design
Consecutive patients with COPD and CHF were recruited from a university rehabilitation centre for rehabilitation program from September 2005 to May 2006. Forty-two COPD and 39 CHF outpatients were included. The data used in this study are a part of a different study that studied the effects of a rehabilitation programme and therefore assessed the COPD and CHF patients both before and after rehabilitation programme participation. COPD patients were included if they were; diagnosed as COPD by a pulmonologist. Patients were eligible for inclusion if they had a FEV1 that was between 30% and 80% of the predicted value (according to the GOLD guideline),5 if their clinical condition was stable at the time of inclusion, and if they had not had any infections or COPD exacerbations in the previous 4 weeks. Exclusion criteria were other disabling conditions or severe diseases and/or coexistence of other causes of impaired pulmonary function. CHF patients were included if they were; diagnosed with CHF by a cardiologist, registered with a LVEF less than 45%. Furthermore, patients with CHF were excluded if they suffered from angina pectoris or atrium fibrillation, if they had heart transplant surgery, or if they had recently (in the past year) had a myocardial infarction, other disabling conditions or severe diseases. The study had a cross-sectional design. Eligible patients received written information about the study and an informed consent form.
Demographic data of all COPD and CHF patients were taken from the patient files. All COPD and CHF patients were assessed by the following methods. Before testing, subjects were familiarized with both the test equipment and the assessmet protocol.
Assessment of dyspnea
The subjects rated the sensation of difficulty in breathing (dyspnea) using a modified Borg scale.6 This scale is a linear scale of numbers ranking the magnitude of difficulty in breathing, ranging from 0 (none) to 10 (maximal).
Pulmonary function test
FEV1% and FEV1/forced vital capacity (FVC)% of COPD patients was assessed using Masterscreen CPX, Viasys Health Care and in accordance with the criteria of American Thoracic Society.7
Transthoracic echocardiography was performed on CHF patients using Hewlett Packard Sonos 2000 device and 2.5 MHz transducer. Measurements were assessed according to the recommendation of the American Thoracic Society.8 LVEF was calculated by modified Simpson’s method.8
Assessment of functional capacity
Functional capacity was assessed in both groups of patients by cardiopulmonary exercise test and shuttle walk test.
Cardiopulmonary exercise test
Exercise testing was administered by the same person on a treadmill (Model 770 CE) with continuous electrocardiogram (ECG) monitoring using modified Naughton protocol.9 Peak VO2 values obtained were recorded (Masterscreen CPX with metabolic cart, Viasys Heathcare, Jaeger, Würzburg, Germany).
Shuttle walk test
In this test, the patient was asked to walk with an increasing pace between two marker cones placed 10 meters apart. Walking speed was adjusted according to bleeps slightly incrementing every minute (0, 17 m/s) that was heard from a tape. The test included 12 stages. The test was terminated when a patient became so breathless that he/she could not keep up with the desired pace. This test was administered to the patients one day before the maximal exercise testing. Results of the second exercise test were used for the analysis.10,11
Quality of life
Quality of life of patients was assessed using SF 36.12 SF 36 is a 36-item questionnaire form which evaluates physical functioning, role-physical, role-emotional, social functioning, general health, mental health, bodily pain and vitality subtitles.
The results were analyzed using the Statistical Package for Social Sciences (SPSS) version 10.0 software system for Windows. To evaluate socio-demographic characteristics, descriptive statistical methods were used. Age-correction was performed when comparing two groups of patients. Results after this correction are presented in the results section. Normality of the variables was tested by Kolmograf Smiroff test. Variables were analyzed by analysis of covariance. Linear correlation between variables was assessed using Pearson’s linear corelation coefficient. P values less than 0.05 were considered statistically significant.
Forty-two COPD (male/female 36/6) and 39 CHF (male/female 24/15) patients were included in the study. Average age of COPD patients and CHF patients was (65.88 ± 8.45) years and (45.51 ± 14.42) years, respectively. Average duration of disease was (141.07 ± 119.53) months in COPD patient group and (44.22 ± 39.23) months in CHF group (P<0.05). There was no significant difference between the two disease groups in terms of co-morbidity (P>0.05, Tables 1 and 2). Average FEV1% was (52.22 ± 15.72)% in COPD patients while average LVEF was (28.59 ± 10.63)% in CHF patients (Tables 1 and 2). No statistically significant difference was found between the two groups with respect to Borg dyspnea score, shuttle walk test and the majority of SF 36 subgroup scores (P>0.05, Table 3). A statistically significant difference was observed in the peak VO2 value in favour of COPD group (P<0.05, Table 3). Only SF 36 physical function subgroup score yielded higher values in COPD patients when compared to the CHF group (P<0.05, Table 3).
Table 1. Demographic and clinical variables in patients with COPD (mean ± SD)
Table 3. Comparison of functional capacity and quality of life between COPD and CHF (mean ± SD)
On the other hand, no relationship was found between objective disease indicators (LVEF and FEV1) and quality of life and functional capacity (P>0.05).
In our study, dyspnea symptom was found associated in both diseases with some aspects of functional capacity and quality of life while indicators of disease severity did not show any association with any of the two. No remarkable difference was observed between the two groups of disease with respect to symptom severity, functional capacity, and quality of life.
Study results related to the handled characteristics of these two diseases show some dissimilarities with our results. In a study by Caroci et al,2 it was reported that dyspnea intensity was greater in COPD patients than that in CHF patients. However, FEV1% values of the mentioned study seem lower than those of our patients. In another study by Arnold et al,1 it was found that self-reported physical functions were worse in COPD patients. However, a comparison cannot be made between the two studies as the methods used are different. It is seen that the two groups of patients have lower scores of quality of life than healthy individuals.13,14 It is emphasized, supporting our conclusion that the effect on quality of life in COPD and CHF patients is in general, parallel in the two groups.3
Although some studies indicate a weak relationship between the symptom of dyspnea and indicators of disease severity (FEV1, LVEF),15-17 there also exist some other studies, like the present study, which maintain that no relationship is evident between them.1,4,15 We believe that finding of no association between objective indicators of health and clinical symptoms is consequential for rehabilitation physicians. As there is no significant relationship between the objective indicators of disease and quality of life and functional capacity, we believe that rehabilitation approaches intended for patients would be more beneficial if they were planned to improve symptoms, functional capacity, and quality of life.
The relationship between dyspnea symptom and quality of life is of importance. Most clinicians conduct patient monitoring and treatments focusing on symptoms. The correlation between dyspnea and quality of life in COPD was also indicated in other studies supportive of our hypothesis.4,18-20 Dyspnea symptom was found by Hajiro et al20 associated with subgroups of SF 36 other than emotional and mental health subtitles, while another study indicated that it was rather associated with mental health.18 In our study, on the other hand, dyspnea symptom was found more associated with the physical component (physical functioning and role-physical) of the patient. With these results, it can be assumed that dyspnea symptoms will probably cause restrictions in the daily life activities of patients.
The relationship between dyspnea symptom and quality of life (particularly physical functioning) is also discussed in CHF.1,4,21 In this study, correlation was observed between dyspnea symptom and social functioning and bodily pain subtitles in CHF patients. This situation can be explained by the fact that CHF patients do not want to socialize with people or they prefer to stay at home due to their disease (dyspnea).
It is reported that FEV1, which is of importance in terms of severity of the disease in COPD patients, has a loose connection with quality of life.15,22 However, FEV1 was found associated with quality of life in some other studies.13,23-25 No association could be established between FEV1 and scores of quality of life in our study. In accordance with other studies, a relationship was found in CHF patients between the objective parameter, LEVF, and quality of life.1,13,26,27 In conclusion, as there exist many factors that affect the quality of life, it must be remembered that objective indicators of health may not be associated with quality of life.
It was reported that FEV1 does not appear to be a predictor of impaired exercise tolerance in COPD patients.28 It is also stated that there was no relationship between LVEF and functional capacity in CHF patients.1,29-31 A relationship was not established in our study either, between the functional capacity and FEV1 or LVEF. Objective health parameters were not directly related to general health perceptions. This indicates that is not the physical disorder per se but rather the resultant limitations in physical functioning that are important determinant of general health perceptions of patients. Although LVEF and FEV1 provide an accurate indication of disease severity, it may be more relevant for clinican to know the physical limitations patients experience and their health compatence as these factors are directly related to patients’ health perceptions and their well-being and therefore may be directive for the treatment of the patients.
The strong points of our study include assessment of functional capacity by use of objective methods and being handled together with quality of life in the same study. Furthermore, we believe that this study will be a resource for studies to follow owing to its feature that it reflects the characteristics of patient groups in our country.
Different patient age means and durations of disease can account for the limitations of this study. However, a special selection could not be made since the patients were chosen among those attending outpatient rehabilitation units. Assessments were made after correction of the statistical method according to age and duration of disease. Similar situations were encountered in other studies as well.1 Limited number of patients and inexistence of a healthy control group can also be considered as a weak aspect.
In conclusion, this study has shown that both functional capacity and quality of life are affected by the disease symptom, however, objective indicators of disease severity do not show such a relationship. These data support the practice of developing a treatment program after focusing on the symptom as currently employed by most clinicians. Therefore, in addition to the objective data related to the disease, we recommend that symptoms should also be taken into consideration to assess cardiopulmonary rehabilitation program and during following-up.
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