ABSTRACT
Pulmonary rehabilitation (PR) is established as an effective intervention in optimising function and quality of life in patients with chronic obstructive pulmonary disease (COPD). However, there are very limited data on the effectiveness of PR in older patients with COPD. We reviewed all patients attending an 8-week outpatient programme. Patients were divided into two groups; Group A (n = 202), below 70 years, and Group B (n = 122), above 70 years of age. Outcomes in both patient subgroups were compared using FEV1, Incremental Shuttle Walk Test (ISWT), Endurance Shuttle Walk Test (ESWT), Grip Strength, St. George's Respiratory Questionnaire (SGRQ), Hospital Anxiety and Depression Score (HADS), and COPD Assessment Test (CAT) score. Statistical analysis was conducted using Mann-Whitney non-parametric testing and chi-square testing for comparison of clinically relevant improvements between groups. There was no significant difference in PR outcomes between Group A and Group B using absolute values. Mean changes in ISWT for Groups A and B 39.7 m vs. 32.8 m (p = 0.63), respectively, SGRQ −2.5 vs. −2.8 (p = 0.95), HADS anxiety score −0.83 vs. −0.57 (p = 0.43) and HADS depression score −0.69 vs. −0.39 (p = 0.48), respectively. There was no difference in the proportion of patients who achieved the minimal clinically significant improvement in Group A versus Group B for parameters ISWT (38.6% vs 42.7%), SGRQ (27.8% vs 21.3%), and HADS total score (20.5% vs 28.1%). These data suggest that benefits of PR in COPD are not age dependent. Age should not be a barrier to enrolling patients with COPD in PR programmes.
Introduction
Chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and mortality worldwide. It is the fourth leading cause of death worldwide and is predicted to be the third most common cause of death by 2020 Citation(1). In Ireland, it is estimated that 400,000 people from a population of 4.58 million experience COPD Citation(2). The prevalence of COPD is increasing in older age groups and is often undertreated (Citation3,Citation4). In the context of an ageing population, it is evident that the health burden of COPD and its co-morbidities will continue to increase and exert a major impact on health services internationally (Citation2,Citation5).
Pulmonary rehabilitation (PR) plays a crucial role in the care of COPD patients and has been shown to improve exercise and functional capacity and reduce exacerbations (Citation1,Citation6,Citation7,Citation8). Many studies have established the effectiveness of PR in improving exercise tolerance, health-related quality of life (HRQoL) as well as reducing dyspnoea, exacerbations and hospitalisations (Citation9–12). Previous PR studies, have excluded patients over the age of seventy (Citation4,Citation13). It is apparent that PR has sometimes been considered inappropriate for older patients because of the physiological effects of ageing, which might limit their ability to take part or improve their exercise capacity. The justification for age exclusion remains ambiguous; nevertheless, patients over the age of 70 years are frequently excluded on the basis of age along with patients with co-morbidities such as severe ischaemic heart disease, heart failure, stroke and arthritis (Citation14,Citation15).
The effectiveness of PR in patients above 70–75 years has been examined in a number of very small studies with numbers ranging between 20 and 45 patients (Citation16–20). Published work in this area has tended to focus on male patients (Citation17,Citation19), has used limited physiological assessments such as 6MWT with little QOL data (Citation16,Citation17,Citation19), and has evaluated patients recruited from elective hospital-based programmes (Citation16–18). Programmes described in some published studies would now be considered too short at 2–4 weeks, to achieve maximal benefit (Citation17–19).
Thus, the existing literature has not convincingly demonstrated that older stable COPD patients respond as well to PR as younger stable patients in an outpatient community-based programme. The aim of this study was to compare the efficacy of PR in a large cohort of stable COPD patients above and below the age of seventy years in a ‘real world’ community-based 8-week program with extensive physiological and quality of life measurements.
Methods
A retrospective review was performed on all patients over the age of 40 years with a confirmed diagnosis of COPD, who completed an 8-week, 16-session, outpatient PR programme over 6 years between 2008 and 2014. The original diagnosis of COPD was based on a history of dyspnoea, chronic cough or sputum production, a history of exposure to risk factors predominantly smoking, and the presence of a post-bronchodilator FEV1/FVC < 0.70 Citation(1). Since this diagnostic definition tends to over-diagnose COPD in the elderly, for the purposes of this study, patients were excluded unless the COPD diagnosis was confirmed using age-specific lower limit of normal (LLN) FEV1/FVC derived from the Global Lung Initiative 2012 Equations, which have been endorsed for international use by the ERS Citation(20).
The outpatient programme based in a local community hospital with gym and educational facilities. Patients were referred to the PR programme through the outpatient service of the Department of Respiratory Medicine, Cork University Hospital, by the lead physician for COPD and PR (MTH). Patients were only excluded if they could not access the facility for logistical reasons or if there was a history of severe unstable cardiac disease, neurologic disease or orthopaedic disease interfering with exercise rendering the patient unsuitable for an outpatient PR programme. Patients had a pre-programme assessment one week before commencing the programme and were deferred to the next programme if there was any suggestion of an exacerbation at that visit or in the week leading up to the programme. Individually prescribed exercise programmes were designed for patients by an experienced COPD physiotherapist and nurse specialist. Full physiological assessments took place before and immediately after completion of the PR programme. Sixteen educational sessions were provided by the consultant respiratory physician, respiratory physiotherapist and COPD nurse specialist, social worker, dietician, professional smoking cessation counsellor and clinical psychologist.
The patients were divided into two groups; Group A below the age of 70, and Group B, 70 years and over. Patient demographics and PR outcomes were collected from the programme database. Outcome measures analysed were forced expiratory volume in one second (FEV1), Incremental Shuttle Walk Test (ISWT) distance, Endurance Shuttle Walk Test (ESWT) time, Grip Strength, St. George's Respiratory Questionnaire (SGRQ) and Hospital Anxiety and Depression Score (HADS), Modified Medical Research Council (mMRC) and COPD Assessment Test (CAT) scores. Data were analysed using SPSS V.21. The efficacy of PR was assessed by comparing the differences in the evaluated parameters between the two groups. Mann-Whitney U test and chi-square test were used to evaluate changes in parameters post-programme by age group in three ways, in keeping with approaches used in previous studies; change in mean raw measures as illustrated in , mean % change from baseline in and proportion of patients achieving minimally clinical significant improvement. For some parameters, the dataset was incomplete, and this is reflected in Tables 1–3. Both Mann-Whitney U and chi-square test were also used to determine whether there was a significant difference between groups defined by clinically significant change Citation(21) in ISWT, SGRQ, HADS and CAT (Citation22–24) corrected for their baseline mean BMI, (dividing the patient cohort into those with BMI < 20 versus those ≥20), FEV1 (those < 1 L versus those ≥ 1 L) and CAT score (those with CAT score < 20 versus those with a score ≥ 20). P-values of less than 0.05 were considered statistically significant throughout. This study was approved by the Clinical Research Ethics Committee (CREC) of the Cork University Hospitals.
Results
A total of 324 COPD patients attending the PR programme were analysed, of whom 202 patients were below the age of 70 years (Group A) and 122 patients were 70 years of age or above (Group B). 306 patients with COPD < 70 years were screened for PR with an inclusion rate of 66%, and similarly 196 patients ≥70 years and above were screened, indicating an inclusion rate of 62%. This very similar inclusion rate indicates that there was no selection bias favouring healthier older patients and suggests that patients over the age of 70 were not excluded from the program on the basis of age or co-morbidity. Reasons given for not taking up the offer of PR were very similar in older. They younger patients. They included factors relating to cardiovascular or neurological co-morbidities in 32% Group A and 36% Group B, distance from the PR program and lack of transport 35% in Group A and 38% in Group B, and patients refusing offers for personal preference 33% in Group A and 26% in Group B.
The BMI of both the groups of patients is recorded in . Younger COPD Group A patients had BMI of 28.5 with a post-bronchodilator FEV1/FVC ratio of 43.4%, and older Group B patients had a BMI of 27.8 with a post-bronchodilator FEV1/FVC ratio of 44.7%.
Table 1. Baseline characteristics (mean value) of the two groups of COPD patients.
In Group A, the mean (SD) age was 61 (3.79) years, while in Group B, it was 75 (6.9) years. Patients' mean baseline characteristics are shown in . shows the mean change in raw measures post PR programme by age group. Mann-Whitney U test showed that there were no significant differences in the changes achieved between the younger Group A patients and the older Group B patients. illustrates the % change in parameters post-programme in order to take into account the differences in baseline parameters between the groups. Again, no significant differences between age groups were found.
Table 2. Shows the mean change in raw measures post PR programme by age group.
Table 3. Illustrates the % change in parameters post-programme in order to take into account the differences in baseline parameters between the groups.
We also compared the proportion of patients achieving clinically significant improvement in parameters between age groups using a chi-square test. Parameters examined were ISWT – (MCID 47.5M) Citation(22), total SGRQ score (MCID-4) Citation(23), total HADS score (MCID 1.5) Citation(24) and CAT score (MCID 2). There is no universally accepted MCID for grip strength.
38.6% of patients in Group A and 42.7% of patients in Group B achieved a MCID in ISWT distance walked post PR programme. This difference was not significant between groups. 27.8% of patients in Group A and 21.3% in Group B achieved MCID in SGRQ score post programme. This difference was not significant between groups. 20.5% of patients in Group A and 28.1% of patients in Group B achieved a MCID in HAD score post PR programme. This difference was not significant between the groups. Finally, 26.5% of Group A patients and 25.9% of patients in Group B achieved MCID in CAT scores post PR programme, and again, there was no significant difference between the groups. Overall taking into account all 3 parameters, 56.2% patients in Group A and 51.4% of patients in Group B achieved an MCID in at least one of the 3 parameters measured, and there was no significant difference between groups.
When we attempted to control for patient cohort baseline FEV1, CAT score and BMI () to determine if these baseline parameters were associated with better outcomes from PR across the group as a whole and in both the younger and older patient cohorts, we found the following: The numbers with low BMI (<18.5) were very small (n = 8), and thus the data were insufficient for comparison. Using both Mann-Whitney U (p = 0.007) and chi-square analysis (p = 0.003), a lower FEV1 (<1 L) pre-programme (at baseline) was associated with a clinically significant improvement in HADS score across the whole population over the course of the PR program. Those with lower FEV1 were found to be most likely to gain improvement in both anxiety and depression scores. This relationship was found to be age independent, and baseline FEV1 < 1 L versus HADS improvement in Group A (p = 0.011) was matched by the improvement in HADS in the low FEV1 in Group B (p = 0.017).
Table 4. The association between baseline characteristics FEV1 (forced expiratory volume in 1 second), BMI (body mass index) and CAT (COPD Assessment Test).
In contrast, in Group A, <70 year old COPD patients, those who achieved a clinically significant improvement of >2 points in CAT score had a higher FEV1 at baseline (≥1 L), (p = 0.01). Looking at baseline CATS scores to define predictors of response, we found the following: A lower baseline CAT is linked to clinically significant change in CAT across age groups. A lower baseline CAT (<20) was linked to clinically significant change in ISWT in Group B (>70 years) but not in Group A; however, a lower baseline CAT (<20) was linked to clinically significant change in SGRQ Group A but not in Group B.
Those who achieved a clinically significant improvement in ISWT had a lower CAT score (<20) at baseline in Group B (p = 0.007, Mann-Whitney U, p = 0.014 chi-square). In Group A, this relationship was significant using comparison of means (p = 0.01) but not by chi-square test. A low CAT score at baseline did not predict improvement of SGRQ scores in Group B but did predict improvement in SQRG in the younger Group A (p = 0.01 Mann-Whitney U, p = 0.05 chi-square).
Discussion
The efficacy of PR is well recognised as a therapeutic intervention in COPD patients; however, the benefits amongst older patients remain unclear. We chose a threshold of seventy years for our study to test the hypothesis that age should not be a barrier to the benefits of PR in COPD. The principal findings of this study suggest that COPD patients over the age of 70 years benefit from a comprehensive outpatient PR programme to a similar extent to patients aged less than 70 years.
From a functional aspect, both patient groups in this study had a negligible difference in their lung function after PR. This is consistent with other studies, which have shown that PR does not have a discernible effect on the FEV1 (Citation9,Citation11).
The ISWT distance increased after PR by 25% (39.7 m) from a baseline of 232 m in Group A and 43% (32.8 m) in Group B, albeit from a lower baseline of 151 m. The older patient group did not attain an improvement that would indicate a significant clinical response. However, as ISWT reflects the domestic functional capacity of an individual, any positive change in exercise performance should be considered beneficial to the patient Citation(22). The same improvement in walk distance gain can have a very different clinical meaning depending upon the baseline performance: a 40-m gain may in fact provide either a negligible or substantial effect of the functional improvement depending upon whether baseline walk distance was 250 m or 100 m. Indeed, there is a strong association between the walk distance and the level of independence in basic and instrumental activities of daily living (ADLs). A comprehensive 12-week outpatient PR programme has been shown to increase both 6-minute walk distance and ADLs Citation(25). Relatively small improvements in walk distance in older patients who naturally have a lower baseline walk distance may correspond to very clinically relevant improvements in ADLs and personal independence, even allowing for modest real improvements as in the case in our study. Similarly, a severe limitation in physical capabilities should not be a reason for excluding older COPD patients from a PR programme; rather, these patients may achieve the greatest benefit (Citation19,Citation26).
We also measured changes in ESWT in our patient cohort. Pepin et al. validated the ESWR in terms of improvements perceived by patients. A change in endurance shuttle walking performance of 45–85 seconds (or 60–115 m) is likely to be perceived by patients Citation(27). Improvements in our study of 78 seconds from a baseline of 341 and 68 seconds from a baseline of 219 seconds in Groups A and B, respectively, are almost certainly going to be perceived as beneficial. Again, there was no significant difference between groups, and the same argument likely applies as to why there is a slightly smaller improvement in the older group who had a lower baseline. This should not detract the very significant clinically important that both the groups achieved after PR with older patients performing as well as their younger counterparts. In the field of COPD research, MID values have usually been reported as fixed values, expressed in the unit of the instrument. When one takes age into account, perhaps MID estimates should be expressed as a fraction of the baseline values (Citation28,Citation29).
We have no MCID for grip strength from literature. Our PR program spent considerable time with patients working on upper limb strength and flexibility. This was reflected in improvements in grip strength in both right and left hands in both Groups A and B. In our cohort, improvement in grip strength also showed no statistically significant difference between the groups. However, it is notable that the relative improvements are larger in the older group who again, not unsurprisingly, started from a lower baseline. The improvement was slightly higher in the right hand, which is most likely accounted by the fact that a higher proportion of people favour their right hand.
PR has also been shown to improve patients' HRQoL. We analysed this using the SGRQ and HADS scores. A reduction of 4 units in SGRQ is considered to be the MCID (Citation21,Citation23). Reductions in SGRQ were similar between the two groups, 2.5 in Group A and 2.8 in Group B. As for the HADS total score (MCID −1.5 units), Group A attained a larger reduction of 0.8, in comparison to Group B with 0.5 reduction Citation(24). Nonetheless, there was no statistically significant difference between the outcomes in both the groups. When the HADS domains were assessed individually, depression scores dropped more than the anxiety scores in both the groups. This is consistent with earlier studies (Citation10,Citation11). This may be explained by the improved functional capacity that uplifts one's spirits and changes their outlook on life. The social aspect of the programme also builds healthy interactions and motivations that may contribute to this positive outcome. It is interesting that in both the groups, those with a lower baseline FEV1 benefitted most in terms of improvement in HADS score with PR, suggesting that in fact, regardless of age, those with more severe COPD may derive most benefit in mood and disease-related anxiety. Similarly, those with more severe disease reflected by a low programme CAT score derived the most significant improvement in CAT score with PR, indicating again that regardless of age, disease severity should not be a barrier to participation in a comprehensive PR programme.
One of the strengths of our study was the large sample size of 324 patients and the long duration of 6 years over which the data were compiled compared to other studies. Katsura demonstrated that PR is an effective treatment in terms of improving dyspnoea, exercise capacity and HRQoL in older COPD patients, and the benefits are almost comparable for young-older patients and old-older patients. However, this was a small study (n = 59) and a 2-week programme Citation(17). Our study involves a much larger cohort over 8 weeks, with patient numbers in both the groups allowing for higher quality analysis to be carried out. Roomi et al. assessed the effects of incremental PR for 12 weeks on older COPD patients over 70 years of age. In a limited small cohort, they showed a significant increase in exercise capacity on the 6MWD Citation(30). Our study, which has the largest described cohort to date of older patients, showed that both patient groups demonstrate comparable improvements in functional and quality of life scores, with a majority of patients exceeding MCID thresholds in more comprehensively measured clinical parameters.
The BMI of both groups of patients, as recorded in , suggests that our patients groups were very definitely not underweight. These figures compare well with other studies such as that of Sulaiman et al. who defined the characteristics of patients with COPD, in a recent separate Irish cohort of 265 patients with a mean age of 71years who were studied for inhaler compliance. The mean BMI of this patient group was 26.8, which suggests that our cohort of patients, BMI 28.5 in Group A and 27.8 in Group B, was representative of an average Irish COPD cohort Citation(31).
The main limitation of this study is that it is retrospective, and we do not have extensive follow-up data on long-term patient outcomes and compliance with exercise post programme. We have a large patient cohort and an 8-week, 16-session programme; however, the data collection though comprehensive, was not complete. While we have recorded the number of patients excluded from the programme because of specific cardiac, neurological or orthopaedic co-morbid conditions, the remaining medical issues of our patient cohort are less well defined. However, they were clearly not severe enough to exclude these patients from the programme. These details may have made the study more informative, to assess their impact on patients' performance post PR. Apart from that, there was no control for both the groups, but it would have been unethical to refuse PR to these COPD patients who remain symptomatic.
Conclusion
In summary, our study suggests that PR is beneficial in both young and older patients COPD patients, although trending slightly better in the younger cohort. Thus, age alone should not be a limiting factor to participate in a PR programme as any improvement may be beneficial to older patients. Patients in all age groups should be encouraged to enrol in this programme as it does have a role in improving health outcomes.
Abbreviations
| COPD | = | Chronic obstructive pulmonary disease |
| PR | = | Pulmonary rehabilitation |
| BMI | = | Body mass index |
| FEV1 | = | Forced expiratory volume in one second |
| FVC | = | Forced vital capacity |
| LLN | = | Lower limit of normal for FEV1 |
| ISWT | = | Incremental shuttle walk test |
| ESWT | = | Endurance shuttle walk test |
| SGRQ | = | St. George's Respiratory Questionnaire |
| HADS | = | Hospital anxiety and depression score |
| CAT | = | COPD Assessment Test |
| HRQoL | = | Health-related quality of life |
| mMRC | = | Modified Medical Research Council score |
| MCID | = | Minimal clinically important difference |
| ADL | = | Activities of daily living |
Author contributions
MTH is the senior author, conceived the project and is the guarantor for the whole content of the manuscript. DB reviewed the data, conducted the statistical analysis and edited drafts of the paper. BB performed the PR and collected the data. PM and AS collected data and performed initials analysis and wrote the first draft. MOC reviewed the data and contributed to the final draft.
Declaration of interest
None of the authors report any conflict of interests. The authors alone are responsible for the content and writing of the paper.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sector.
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