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.