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Not all patients with chronic obstructive pulmonary disease (COPD) respond equally well to pulmonary rehabilitation (PR).
Now, physicians can better categorize which patients will do well with PR and which ones less well or not well at all based on a new system of clustering of COPD patients according to their response to exercise therapy.
“We identified four clusters of COPD patients and their response to PR in the aim to better understand PR outcome and [adapt] it to patients’ profiles and needs,” lead author Yara Al Chikhanie, MD, of the cardiopulmonary rehabilitation center Dieulefit Sante (France), and colleagues observed.
“Identification of patients likely to show smaller responses to PR may help to target patients benefiting the most and to adapt PR settings for nonresponders to standard PR,” they suggested.
The study was published online in Respiratory Medicine.
Single-center cohort
The cohort consisted of 835 patients from a single center who had been admitted to a cardiopulmonary rehabilitation center over a 6-year period from 2021 to 2017. “The PR program used in the center was the same over the 6-year period,” the authors note – consisting of a 3- to 4-week, inpatient program with activities 5 days a week.
Each day, patients attended a 25-minute aerobic training session on a cycling ergometer or a treadmill; a 30-minute low-intensity gym session; a 30-minute group walk outdoors, and 30 minutes of strength training. “We aimed to cluster patients with COPD admitted to PR based on patients’ clinical characteristics and 6-meter walk test results (6MWT), pulse oxygen saturation (SPO2), heart rate (HR), and dyspnea,” the authors explained.
They then evaluated patient response to PR in each of these clusters based on the amount of improvement in the 6-meter walk distance (6MWD), lung function, and quality of life observed, they added.
The population consisted of seniors, equally men and women, mostly GOLD II and III patients (a measure of lung function) with a limited walking capacity, some 84% of the cohort having a 6MWD <80% predicted. The characteristics of the four identified clusters were as follows:
- Cluster 1: Consisted of younger men, GOLD I to II, average walkers, obese. The average 6MWD was 430 meters and patients had a large exercise HR response to PR. This cluster had a 76 meter improvement in their 6MWD, although 16% of the same cluster still did not respond to PR.
- Cluster 2: Consisted of older women, GOLD II-III, who were slow walkers. This cluster had a reduced 6MWD of 362 meters, but they also had a significant 97-meter improvement in their 6MWD following PR. Some 18% were still nonresponders to PR.
- Cluster 3: Consisted of older men, GOLD II to III, dyspneic, slow walkers, some 32% of whom responded to PR. This cluster also had a reduced 6MWD at 388 meters, but again, they also had a significant improvement of 79 meters in their 6MWD following the introduction of PR. Some 11% were nonresponders to PR.
- Cluster 4: Consisted of older men, GOLD III to IV, very slow walkers, oxygen-dependent, very dyspneic. This cluster had a severely reduced 6MWD of only 290 meters with severe exercise desaturation and dyspnea, and almost all of them were on long-term oxygen therapy. Nevertheless, this cluster also had a significant, 66-meter improvement in their 6MWD. Twenty-eight percent of them were nonresponders to PR.
Clinical practice
“The highly heterogeneous nature of the enrolled patient population reflects clinical practice,” the authors point out. For example, cluster 1 included patients with the best lung function, compared with those in clusters 2, 3, and 4 – which may be due, at least in part, to the aggravation in disease severity with age given that patients in cluster 1 were the youngest overall.
The fact that those in cluster 4 had the worst performance may also have been because of age and disease severity, the authors note, as those in cluster 4 had the highest proportion of patients on long-term oxygen therapy, again suggestive of disease severity. “Of note, these patients show the most impaired 6MWT responses despite the use of oxygen supplementation during walking,” the researchers added.
The authors also suggest that patients such as those in cluster 4 may require specific PR modalities in order to optimize their functional benefits. In contrast, those in cluster 1 had a significantly higher body mass index, compared with those in the other 3 clusters, which, interestingly enough, was not associated with more severe functional exercise impairment. The fact that older age participants, such as those in cluster 3 as well as those with high BMI in cluster 1, were both able to improve their 6MWD post-PR to the same extent as younger patients without obesity suggests that most older or overweight/obese patients can still show clinically significant improvement in 6MWD post PR, as the authors suggest.
Notably, the 6MWT was the only test available both pre-and post PR, making this an important limitation of the study, because only one aspect of the effect of PR was evaluated, omitting other physical and psychosocial benefits of PR, investigators suggest.
Adds to the literature
Asked to comment on the findings, Sachin Gupta, MD, attending physician, pulmonary & critical care medicine, Alameda Health System, Highland Hospital, Oakland, Calif., felt that these data add to the literature in defining COPD patient profiles, helping to categorize those in whom to expect greater walk distance improvements with PR versus those who will respond less well.
“Because 6MWD is a surrogate marker for quality of life (QOL) and mortality, further analysis in the form of a randomized controlled trial to determine long-term outcomes among the four clusters with adjustment for baseline characteristics would help determine the extent to which certain patient clusters may respond to PR,” Dr. Gupta told this news organization in an email.
At the same time, he suggested that while patients may not experience much net benefit in their 6MWD, their QOL or mortality risk may still improve with PR. “I cannot recall a patient ever describing their experience with PR as anything other than positive,” Dr. Gupta stressed.
“And as the authors [themselves] note, because PR serves to benefit patients beyond the 6MWD, I would not recommend limiting PR referrals based on the patient clusters identified,” he said.
The authors had no conflicts of interest to declare. Dr. Gupta declared that he is an employee and shareholder at Genentech.
Not all patients with chronic obstructive pulmonary disease (COPD) respond equally well to pulmonary rehabilitation (PR).
Now, physicians can better categorize which patients will do well with PR and which ones less well or not well at all based on a new system of clustering of COPD patients according to their response to exercise therapy.
“We identified four clusters of COPD patients and their response to PR in the aim to better understand PR outcome and [adapt] it to patients’ profiles and needs,” lead author Yara Al Chikhanie, MD, of the cardiopulmonary rehabilitation center Dieulefit Sante (France), and colleagues observed.
“Identification of patients likely to show smaller responses to PR may help to target patients benefiting the most and to adapt PR settings for nonresponders to standard PR,” they suggested.
The study was published online in Respiratory Medicine.
Single-center cohort
The cohort consisted of 835 patients from a single center who had been admitted to a cardiopulmonary rehabilitation center over a 6-year period from 2021 to 2017. “The PR program used in the center was the same over the 6-year period,” the authors note – consisting of a 3- to 4-week, inpatient program with activities 5 days a week.
Each day, patients attended a 25-minute aerobic training session on a cycling ergometer or a treadmill; a 30-minute low-intensity gym session; a 30-minute group walk outdoors, and 30 minutes of strength training. “We aimed to cluster patients with COPD admitted to PR based on patients’ clinical characteristics and 6-meter walk test results (6MWT), pulse oxygen saturation (SPO2), heart rate (HR), and dyspnea,” the authors explained.
They then evaluated patient response to PR in each of these clusters based on the amount of improvement in the 6-meter walk distance (6MWD), lung function, and quality of life observed, they added.
The population consisted of seniors, equally men and women, mostly GOLD II and III patients (a measure of lung function) with a limited walking capacity, some 84% of the cohort having a 6MWD <80% predicted. The characteristics of the four identified clusters were as follows:
- Cluster 1: Consisted of younger men, GOLD I to II, average walkers, obese. The average 6MWD was 430 meters and patients had a large exercise HR response to PR. This cluster had a 76 meter improvement in their 6MWD, although 16% of the same cluster still did not respond to PR.
- Cluster 2: Consisted of older women, GOLD II-III, who were slow walkers. This cluster had a reduced 6MWD of 362 meters, but they also had a significant 97-meter improvement in their 6MWD following PR. Some 18% were still nonresponders to PR.
- Cluster 3: Consisted of older men, GOLD II to III, dyspneic, slow walkers, some 32% of whom responded to PR. This cluster also had a reduced 6MWD at 388 meters, but again, they also had a significant improvement of 79 meters in their 6MWD following the introduction of PR. Some 11% were nonresponders to PR.
- Cluster 4: Consisted of older men, GOLD III to IV, very slow walkers, oxygen-dependent, very dyspneic. This cluster had a severely reduced 6MWD of only 290 meters with severe exercise desaturation and dyspnea, and almost all of them were on long-term oxygen therapy. Nevertheless, this cluster also had a significant, 66-meter improvement in their 6MWD. Twenty-eight percent of them were nonresponders to PR.
Clinical practice
“The highly heterogeneous nature of the enrolled patient population reflects clinical practice,” the authors point out. For example, cluster 1 included patients with the best lung function, compared with those in clusters 2, 3, and 4 – which may be due, at least in part, to the aggravation in disease severity with age given that patients in cluster 1 were the youngest overall.
The fact that those in cluster 4 had the worst performance may also have been because of age and disease severity, the authors note, as those in cluster 4 had the highest proportion of patients on long-term oxygen therapy, again suggestive of disease severity. “Of note, these patients show the most impaired 6MWT responses despite the use of oxygen supplementation during walking,” the researchers added.
The authors also suggest that patients such as those in cluster 4 may require specific PR modalities in order to optimize their functional benefits. In contrast, those in cluster 1 had a significantly higher body mass index, compared with those in the other 3 clusters, which, interestingly enough, was not associated with more severe functional exercise impairment. The fact that older age participants, such as those in cluster 3 as well as those with high BMI in cluster 1, were both able to improve their 6MWD post-PR to the same extent as younger patients without obesity suggests that most older or overweight/obese patients can still show clinically significant improvement in 6MWD post PR, as the authors suggest.
Notably, the 6MWT was the only test available both pre-and post PR, making this an important limitation of the study, because only one aspect of the effect of PR was evaluated, omitting other physical and psychosocial benefits of PR, investigators suggest.
Adds to the literature
Asked to comment on the findings, Sachin Gupta, MD, attending physician, pulmonary & critical care medicine, Alameda Health System, Highland Hospital, Oakland, Calif., felt that these data add to the literature in defining COPD patient profiles, helping to categorize those in whom to expect greater walk distance improvements with PR versus those who will respond less well.
“Because 6MWD is a surrogate marker for quality of life (QOL) and mortality, further analysis in the form of a randomized controlled trial to determine long-term outcomes among the four clusters with adjustment for baseline characteristics would help determine the extent to which certain patient clusters may respond to PR,” Dr. Gupta told this news organization in an email.
At the same time, he suggested that while patients may not experience much net benefit in their 6MWD, their QOL or mortality risk may still improve with PR. “I cannot recall a patient ever describing their experience with PR as anything other than positive,” Dr. Gupta stressed.
“And as the authors [themselves] note, because PR serves to benefit patients beyond the 6MWD, I would not recommend limiting PR referrals based on the patient clusters identified,” he said.
The authors had no conflicts of interest to declare. Dr. Gupta declared that he is an employee and shareholder at Genentech.
Not all patients with chronic obstructive pulmonary disease (COPD) respond equally well to pulmonary rehabilitation (PR).
Now, physicians can better categorize which patients will do well with PR and which ones less well or not well at all based on a new system of clustering of COPD patients according to their response to exercise therapy.
“We identified four clusters of COPD patients and their response to PR in the aim to better understand PR outcome and [adapt] it to patients’ profiles and needs,” lead author Yara Al Chikhanie, MD, of the cardiopulmonary rehabilitation center Dieulefit Sante (France), and colleagues observed.
“Identification of patients likely to show smaller responses to PR may help to target patients benefiting the most and to adapt PR settings for nonresponders to standard PR,” they suggested.
The study was published online in Respiratory Medicine.
Single-center cohort
The cohort consisted of 835 patients from a single center who had been admitted to a cardiopulmonary rehabilitation center over a 6-year period from 2021 to 2017. “The PR program used in the center was the same over the 6-year period,” the authors note – consisting of a 3- to 4-week, inpatient program with activities 5 days a week.
Each day, patients attended a 25-minute aerobic training session on a cycling ergometer or a treadmill; a 30-minute low-intensity gym session; a 30-minute group walk outdoors, and 30 minutes of strength training. “We aimed to cluster patients with COPD admitted to PR based on patients’ clinical characteristics and 6-meter walk test results (6MWT), pulse oxygen saturation (SPO2), heart rate (HR), and dyspnea,” the authors explained.
They then evaluated patient response to PR in each of these clusters based on the amount of improvement in the 6-meter walk distance (6MWD), lung function, and quality of life observed, they added.
The population consisted of seniors, equally men and women, mostly GOLD II and III patients (a measure of lung function) with a limited walking capacity, some 84% of the cohort having a 6MWD <80% predicted. The characteristics of the four identified clusters were as follows:
- Cluster 1: Consisted of younger men, GOLD I to II, average walkers, obese. The average 6MWD was 430 meters and patients had a large exercise HR response to PR. This cluster had a 76 meter improvement in their 6MWD, although 16% of the same cluster still did not respond to PR.
- Cluster 2: Consisted of older women, GOLD II-III, who were slow walkers. This cluster had a reduced 6MWD of 362 meters, but they also had a significant 97-meter improvement in their 6MWD following PR. Some 18% were still nonresponders to PR.
- Cluster 3: Consisted of older men, GOLD II to III, dyspneic, slow walkers, some 32% of whom responded to PR. This cluster also had a reduced 6MWD at 388 meters, but again, they also had a significant improvement of 79 meters in their 6MWD following the introduction of PR. Some 11% were nonresponders to PR.
- Cluster 4: Consisted of older men, GOLD III to IV, very slow walkers, oxygen-dependent, very dyspneic. This cluster had a severely reduced 6MWD of only 290 meters with severe exercise desaturation and dyspnea, and almost all of them were on long-term oxygen therapy. Nevertheless, this cluster also had a significant, 66-meter improvement in their 6MWD. Twenty-eight percent of them were nonresponders to PR.
Clinical practice
“The highly heterogeneous nature of the enrolled patient population reflects clinical practice,” the authors point out. For example, cluster 1 included patients with the best lung function, compared with those in clusters 2, 3, and 4 – which may be due, at least in part, to the aggravation in disease severity with age given that patients in cluster 1 were the youngest overall.
The fact that those in cluster 4 had the worst performance may also have been because of age and disease severity, the authors note, as those in cluster 4 had the highest proportion of patients on long-term oxygen therapy, again suggestive of disease severity. “Of note, these patients show the most impaired 6MWT responses despite the use of oxygen supplementation during walking,” the researchers added.
The authors also suggest that patients such as those in cluster 4 may require specific PR modalities in order to optimize their functional benefits. In contrast, those in cluster 1 had a significantly higher body mass index, compared with those in the other 3 clusters, which, interestingly enough, was not associated with more severe functional exercise impairment. The fact that older age participants, such as those in cluster 3 as well as those with high BMI in cluster 1, were both able to improve their 6MWD post-PR to the same extent as younger patients without obesity suggests that most older or overweight/obese patients can still show clinically significant improvement in 6MWD post PR, as the authors suggest.
Notably, the 6MWT was the only test available both pre-and post PR, making this an important limitation of the study, because only one aspect of the effect of PR was evaluated, omitting other physical and psychosocial benefits of PR, investigators suggest.
Adds to the literature
Asked to comment on the findings, Sachin Gupta, MD, attending physician, pulmonary & critical care medicine, Alameda Health System, Highland Hospital, Oakland, Calif., felt that these data add to the literature in defining COPD patient profiles, helping to categorize those in whom to expect greater walk distance improvements with PR versus those who will respond less well.
“Because 6MWD is a surrogate marker for quality of life (QOL) and mortality, further analysis in the form of a randomized controlled trial to determine long-term outcomes among the four clusters with adjustment for baseline characteristics would help determine the extent to which certain patient clusters may respond to PR,” Dr. Gupta told this news organization in an email.
At the same time, he suggested that while patients may not experience much net benefit in their 6MWD, their QOL or mortality risk may still improve with PR. “I cannot recall a patient ever describing their experience with PR as anything other than positive,” Dr. Gupta stressed.
“And as the authors [themselves] note, because PR serves to benefit patients beyond the 6MWD, I would not recommend limiting PR referrals based on the patient clusters identified,” he said.
The authors had no conflicts of interest to declare. Dr. Gupta declared that he is an employee and shareholder at Genentech.
FROM RESPIRATORY MEDICINE