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Purpose: It has been hypothesized that lung volume reduction surgery (LVRS) and pulmonary rehabilitation improve health-related quality of life (HRQOL). The purpose of this study was to test the hypothesis by examining the long-term functional consequences and general health status of patients with emphysema who have undergone LVRS and pulmonary rehabilitation. Methods: Forty-nine subjects with severe emphysema, aged 51 to 84 years old, post-LVRS and pulmonary rehabilitation participated in this study. Subjects reported changes in physical and mental domains on the Medical Outcomes Study 36-Item Short Form Health Survey (MOS SF-36) over 3 time periods: prior to surgery, 6 months postsurgery, and 18 months postsurgery. The population as a whole was studied and both gender and age were analyzed as subsets. Subjects participated in an intensive 2-week (10 daily sessions) pulmonary rehabilitation program following LVRS. Results: Subjects showed significant improvements in both the physical and mental component summaries at Time 2 (3 months post-LVRS through 6 months post-LVRS) and Time 3 (12 months post-LVRS through 18 months post-LVRS) when compared to Time 1 (pre-LVRS). On the mental component summary scale, subjects younger than 65 years old had significant improvement compared to subjects 65 years and older at Time 3 (P < .05). Women significantly improved more than men at Time 3 on the physical component summary scale (P < .05). Conclusions: Lung volume reduction surgery and 2 weeks (10 daily sessions) of intensive pulmonary rehabilitation appears to improve HRQOL in people with emphysema up to at least 18 months postsurgery. What these data further suggest is that even after declines in health, women can improve HRQOL later in life, and that greater focus should be given to the emotional needs of our older patients.
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States, and it is estimated that it will be the third leading cause of mortality in the United States by 2020.1 It is the only leading cause of death with a rising prevalence, accounting for more than 130,000 deaths annually.2 Emphysema is a progressive form of COPD with significant physical and psychological sequelae.
While a variety of treatments improve the symptoms and quality of life in people with COPD, such as bronchodilators, corticosteroids, and pulmonary rehabilitation, these interventions remain supportive and have not impacted survival in people with end-stage emphysema.3–5 Long-term oxygen therapy (> 15 hours/day)6 and smoking cessation7 have been the only therapies shown to improve survival in advanced emphysema.5 Lung volume reduction surgery (LVRS) is one of a long lineage of surgical approaches to emphysema and was reintroduced by Cooper in the early 1990s.8 The National Emphysema Treatment Trial (NETT)9 demonstrated that LVRS improves survival in a select group of patients with emphysema and this was the first time a new treatment impacted survival since the publication of the supplemental oxygen trials almost 30 years ago.6,10
In addition to improving survival, LVRS improves lung function, dyspnea, and exercise tolerance in selected patients with advanced pulmonary emphysema.8,9,11–14 Some investigators argue that symptom relief, dyspnea reduction, improvements in exercise tolerance, and quality of life may be more important to patients than survival when considering LVRS as a treatment option.15 Although data on patients with emphysema are limited, increasing evidence suggests that health-related quality of life (HRQOL) deteriorates with advanced disease and is related to the degree of airflow obstruction and level of dyspnea.16 Pulmonary rehabilitation is an integral part of the recovery from LVRS and is recommended as a component of care in current practice guidelines because of the resultant improvement in conditioning and quality of life.4,5,17
Both general and disease-specific quality of life measures have been developed and used in COPD clinical studies such as the quality-of-well-being scale (QWB-SA),18 the medical outcomes study 36-item short form (MOS SF-36),19,20 the St. George's Respiratory Questionnaire (SGRQ),21 and the University of California, San Diego, shortness-of-breath questionnaire (SOBQ).22 The MOS SF-36 is the instrument used in this study and is a general quality-of-life questionnaire that measures both physical and mental health concepts as seen from the respondent's point of view.19,23 There are few studies that have reported on the effects of LVRS on quality of life as measured with the MOS SF-36. Some have reported improvement in aspects of quality of life with the MOS SF-36 after LVRS for up to 3 months (significant improvements in the scales of physical functioning, social functioning, general health, and vitality),8 6 months (significant improvements in the scales of physical functioning, physical role limitations, general health, vitality, and a mean change in Physical Component Summary measure [PCS]),14,24,25 and only a small number of patients have been followed for longer periods (significant improvements in median score after 1 year; in scales of physical functioning, social functioning, and vitality after 2 years; and in the PCS measure after 5 years).12,13,26,27 Although studies of HRQOL after LVRS have been published, the unique feature of this study is the long-term follow-up of patients after LVRS and intensive pulmonary rehabilitation on both the Physical Component Summary (PCS) and the Mental Component Summary (MCS) in order to illustrate the nature of improvement in HRQOL.
The main purpose of this study was to report on the efficacy of LVRS followed by a 2-week (10 daily sessions) intensive pulmonary rehabilitation program on HRQOL over time with 18 months of follow-up. This research considered the roles of age and gender on HRQOL as important secondary outcomes. From a public health perspective, the investigation of age and gender is timely, because in 2000, the number of women dying of COPD surpassed the number of men.1
The subjects for this study were 49 patients with emphysema who had undergone LVRS and participated in pulmonary rehabilitation after LVRS in a single center clinical trial at Chapman Medical Center (Orange, CA). Subjects in this study were not enrolled in the National Emphysema Treatment Trial. There were 31 men and 18 women in the population analyzed with an age range of 51 to 84 years old. The mean age of the patients was 66.0 ± 6.7 years.
Bilateral staple LVRS by video-assisted thoracic surgery (VATS) was performed by one or both of two thoracic surgeons on the same surgical team. To qualify for surgery, the pattern of the patient's emphysema on computerized tomography (CT) had to be severe and heterogeneous. Radionuclide lung perfusion scans were also used to confirm the heterogeneous pattern of emphysema. Exclusion criteria for surgery included current cigarette smoking, severe cardiac disease (congestive heart failure, significant coronary or valvular disease), history of cancer within the last 5 years, ventilator dependency, or prior thoracic surgery.
No patients received preoperative pulmonary rehabilitation at Chapman Medical Center prior to LVRS. The mean length of hospital stay post-LVRS was 8.8 ± 5.6 days. All patients underwent a similar regimen of intensive 2-week (10 daily sessions) outpatient pulmonary rehabilitation 4 hours/day for 5 days/week at Chapman Medical Center beginning the day following hospital discharge. In accordance with evidence-based guidelines,4,17 the rehabilitation included a multidisciplinary approach with dietary, nursing, nutritional, physical therapy, psychosocial, occupational, and respiratory therapy. The pulmonary rehabilitation program included patient education, physical exercise (ambulation, strengthening, and stretching), self-monitoring, breathing retraining, and airway clearance instruction. The attendance rate was 100%. No home exercise program was given during the rehabilitation phase.
The Medical Outcomes Study 36-Item Short Form Health Survey (MOS SF-36) was the chosen instrument because it is comprehensive in both its representation of multidimensional health concepts and its measurement of a wide range of health states. It is a 36-item general measure, as opposed to one that targets a certain disease, age, or treatment group. It has been shown to be a valid and reliable instrument to measure health-related quality of life (HRQOL) in patients with COPD.28,29 The survey was used to assess subjects' perceived levels of function during the 4 weeks prior to the administration of each survey. The MOS SF-36 has nine separate scales including the following: (1) physical functioning, (2) social functioning, (3) role limitations (physical), (4) role limitations (emotional), (5) emotional well-being, (6) energy/fatigue, (7) pain, (8) general health perceptions, and (9) current general health perceptions compared to 1 year ago.19,23 Data from the ninth scale were excluded from data analyses because they are typically not reported. The sensitivity of measurement for each concept is achieved by a short multi-item scale which is scored using the Likert method of summated ratings.19,23 All 8 scales are used to calculate the 2 component summary measures.20 The physical component summary (PCS) measure represents the four physical health scales (ie, physical functioning, role physical, bodily pain, and general health perceptions), while the mental component summary (MCS) measure reflects the 4 mental health scales (ie, mental health, role emotional, vitality, and social functioning). The two summary scores are standardized so that the general population mean score is 50 points with a standard deviation of 10 points for each summary score. The two summary scores were used in this study. These component scores have been demonstrated to explain 70% to 80% of the variance in the individual domain scores, however, the component scores may not have as good a sensitivity for detecting change as the individual domain scores.30 Higher scores indicate better health status. A clinically relevant change or the “minimally important difference” (MID) of the SF-36 is reported to be 5 units on each summary score, although this has not been replicated in patients with COPD.31
All patients provided written informed consent, and the study was approved by the Institutional Review Board at Chapman Medical Center. The MOS SF-36 was administered at the preoperative evaluation and the opportunity to ask any questions was given. The MOS SF-36 surveys were requested from subjects postoperatively at the following time periods: 3 months, 6 months, 12 months, and 18 months. A pre-LVRS survey for each patient served as the baseline for comparison with the post-LVRS data of that patient. The survey was scored according to the protocol established by the MOS SF-36 scoring manual.20,31 The scores were transformed into a scale ranging from 0 to 100, with 0 denoting poor health.20,31
All data analyses were performed using SPSS 16.0 for Windows (SPSS Inc. Chicago, Il). A research design of group × time with stratification for age and gender was used. Groups with nonsignificant differences for time were compressed when stratifying for age and gender. Patients were divided into 2 age groups: younger than 65 years (n=23) and 65 years and older (n=26).32 Data were compressed into the following times: 3 months post-LVRS through 6 months post-LVRS (Time 2) and 12 through 18 months post-LVRS (Time 3) for comparison with pre-LVRS baseline data (Time 1). A repeated measures multivariate analysis of variance (MANOVA, Wilk's criterion) was performed to examine the effects of time on component summary measures in all subjects and in groups stratified by age and gender. Post-hoc analysis of significant data was determined with the Scheffe's Comparison. Alpha was set at P < .05.
The effect of time was analyzed on both the PCS and MCS measures in all subjects and in groups stratified by age and gender. There was a main effect for time on both the PCS and MCS measures in all subjects. There were significant increases in the mean scores for both Physical and Mental Component Summary measures (PCS and MCS, respectively) at Times 2 and 3 compared to Time 1, P < .05 (Table (Table1).1). Analysis between Time 2 and Time 3 failed to reveal significant increases in component summary measures.
There was a main effect for time on MCS when groups were stratified by age. There was a significant improvement for patients younger than 65 years old compared to those 65 years and older at Time 3 on the MCS, P < .05 (Table (Table2).2). The interaction for time with age was significant on the MCS, P < .05 (Figure (Figure1).1). Older subjects had higher mean MCS measures than younger patients preoperatively, but lower measures postoperatively at both Times 2 and 3.
There was a main effect for time on PCS when groups were stratified by gender. There were significant improvements for women compared to men at Time 3 on the PCS, P < .05 (Table (Table3).3). A significant time-gender interaction occurred on the PCS, P < .05 (Figure (Figure2).2). Men had higher mean PCS measures than women preoperatively, but lower PCS measures postoperatively at both Times 2 and 3.
There are few published studies that have evaluated either the HRQOL for patients with severe emphysema or the impact of interventions on HRQOL measures. This study has shown that LVRS and pulmonary rehabilitation can significantly improve health-related quality of life (HRQOL) in people with emphysema. Lung volume reduction surgery is able to improve HRQOL by improving lung function (forced expiratory volume in the first second and/or lung volumes), dyspnea, and exercise tolerance in selected patients with advanced pulmonary emphysema.8,9,11–14 Pulmonary rehabilitation is able to improve HRQOL by improving dyspnea,33–35 exercise tolerance,11,14,36 education, and coping strategies while having no effect on pulmonary physiology or function or improved survival in patients with COPD.4 Pulmonary rehabilitation improves physical deconditioning, peripheral muscle abnormalities, improper pacing during exercise, and fear of dyspnea-producing activities which contribute to the systemic effects of COPD and much of its morbidity.17,37 The NETT established that pulmonary rehabilitation is essential for patients after LVRS.38–40 The combination of LVRS and pulmonary rehabilitation provides the greatest benefit for selected patients with severe emphysema, well above the effects of either intervention alone.24
Prior to LVRS and rehabilitation, the HRQOL of this study's subjects, as reflected by the Physical Component Summary measure, was profoundly impaired. Preoperatively, the SF-36 mean PCS measure was 25.3 ± 6.2, which is below both the general U.S. population norms (50 ± 10)31 and norms for people with severe emphysema (28.3 ± 7.4).41 Lower levels of PCS in patients with lung disease predict higher mortality.42 According to these data there is a significant self-reported improvement in the PCS measure from baseline to Times 2 and 3 on the MOS SF-36 following LVRS and rehabilitation (25.3 ± 6.2, 34.8 ± 10.7, and 32.7± 11.7, respectively). The improvement in the PCS measure was similar in studies with LVRS. Yusen et al27 reported means of 26, 40, 35, and 31 on the PCS at baseline, 6 months, 3 years, and 5 years post-LVRS, respectively. There is strong scientific evidence that pulmonary rehabilitation improves HRQOL in patients with COPD, too.4 Ten weeks of pulmonary rehabilitation, prior to LVRS, improved the PCS measure by a mean change of 2.2 ± 6.8 as reported by the NETT.41
Preoperatively, the impairments were less pronounced with respect to the Mental Component Summary measure (46.0 ±13.2) compared to the U.S. population norms (50 ± 10) and norms for people with severe emphysema (50 ± 15).43 Subjects significantly improved their MCS measure from baseline to both Times 2 and 3 (46 ± 13.2, 53.8 ± 10.2, and 52.8 ± 9.8, respectively). Significant improvements in MCS are corroborated by other researchers who reported similar improvements after LVRS and pulmonary rehabilitation, however, those data are reported differently than data from this study such as scales of mental health, median values, or quality adjusted values and therefore direct comparison with the MCS measure from this study is not possible. The MCS measure is most correlated with the mental health, role-emotional, and social functioning scales from the SF 36.31 There was a significant mean 2.1 improvement after rehabilitation in the MCS after pulmonary rehabilitation in the NETT.41
Advancing age is a strong predictor of mortality in people with emphysema.44 Patients younger than 65 years old showed significantly improved scores on the MCS at Time 3 compared to subjects 65 years and older (55.9 ± 6.6 and 50.0 ± 11.3, respectively). Anxiety and depression often accompany COPD and approximately 45% of patients with moderate-to-severe COPD have depressive symptoms.45 Furthermore, depression may increase the sensation of breathlessness.46,47 While the data suggest similar gains until 18 months post-LVRS and rehabilitation between the 2 age groups, the results indicate greater focus should be given to the emotional needs of our older patients.
There are gender differences in the natural history of emphysema. Women were significantly more improved than men at Time 3 on the PCS. Hamacher et al26 did not find any significant differences between the MOS SF-36 responses of 39 men and women 24 months following LVRS. The Nurse's Health Study reports that women whose general mental health (as determined by the MCS measure) was initially poor and had improved over 4 years did not experience a higher mortality than did those whose health remained consistently good over the same time period.48 What these data suggest is that even after declines in health, women can improve HRQOL later in life, and that improvement may help to delay mortality.
It has been suggested that disease-specific measures are significantly more responsive to clinical change compared to general measures of HRQOL.49 Evidence from this study indicates that the MOS SF-36, a general measure of HRQOL, was able to detect significant clinical change following LVRS and rehabilitation. General measures have some advantage because comparisons can be made with other benchmarks. For example, the impact of COPD can be compared with the impact of other chronic diseases. Subjects at baseline in this study were comparable to patients with lumbar stenosis (PCS=26.6).50 Their HQOL was lower than patients with cancer (PCS=38.4).51 These comparisons cannot be made with disease-specific measures.
The question has been raised as to what portion of the measured benefits is attributable to the operation per se and what portion is attributable to the ongoing rehabilitation. Miller et al14 compared the efficacy of LVRS and medical treatment (including pulmonary rehabilitation and pharmacologic therapy) and showed that the LVRS group had a significantly better outcome on the PCS of the SF-36 than the medically treated group after 6 months, whereas the MCS was not significantly different between the 2 groups. Although surgeons attempt to restore improvements in lung function through LVRS, the affective issues concerning this disease cannot be dealt directly with surgery. Patients with emphysema experience their disease differently from each other both physically and affectively. These differences, which may limit function, must be addressed independently with each patient.19,23,52 It is critical for optimal treatment that all health professionals, including physical therapists, take into account differences among disability, subjective evaluations of personal health, and general well-being.23,53
These results seem to indicate an increased ability to perform activities of daily living post-LVRS. According to self-report on the MOS SF-36, patients after surgery and rehabilitation are better able to perform vigorous activities such as lifting heavy objects and moderate activities such as pushing a vacuum or playing golf. Patients also report improvements in carrying groceries, ascending stairs, bending down, walking farther distances, and bathing themselves.
Research is needed to define the exact contributions of pulmonary rehabilitation in other forms of lung disease and for other pulmonary interventions. There is strong scientific evidence that postoperative pulmonary rehabilitation allows the maximum benefit to be realized from LVRS. Work needs to determine the mechanism that improves survival with LVRS to enhance these treatment effects and produce even more potent and durable responses to therapy. Further work is needed to compare other HRQOL measures, develop standardized methods for assessing the minimally important difference for this population, and to translate the measures' scores into clinically meaningful results.
Lung volume reduction surgery and 2 weeks (10 daily sessions) of intensive pulmonary rehabilitation appears to improve quality of life in patients with emphysema up to at least 18 months postsurgery. According to the responses extracted from the MOS SF-36, the physical and mental limitations associated with emphysema are not as great after surgery and rehabilitation. More research is needed to assess the long-term effects beyond 18 months.
Patients < 65 years significantly improved at Time 3 compared to older patients, P<.05
Women significantly improved at Time 3 compared to men, P<.05