The respiratory physiome: Clustering based on a comprehensive lung function assessment in patients with COPD

Abstract

BackgroundWhile spirometry and particularly airflow limitation is still considered as an important tool in therapeutic decision making, it poorly reflects the heterogeneity of respiratory impairment in chronic obstructive pulmonary disease (COPD). The aims of this study were to identify pathophysiological clusters in COPD based on an integrated set of standard lung function attributes and to investigate whether these clusters can predict patient-related outcomes and differ in clinical characteristics.MethodsClinically stable COPD patients referred for pulmonary rehabilitation underwent an integrated assessment including clinical characteristics, dyspnea score, exercise performance, mood and health status, and lung function measurements (post-bronchodilator spirometry, body plethysmography, diffusing capacity, mouth pressures and arterial blood gases). Self-organizing maps were used to generate lung function based clusters.ResultsClustering of lung function attributes of 518 patients with mild to very severe COPD identified seven different lung function clusters. Cluster 1 includes patients with better lung function attributes compared to the other clusters. Airflow limitation is attenuated in clusters 1 to 4 but more pronounced in clusters 5 to 7. Static hyperinflation is more dominant in clusters 5 to 7. A different pattern occurs for carbon monoxide diffusing capacity, mouth pressures and for arterial blood gases. Related to the different lung function profiles, clusters 1 and 4 demonstrate the best functional performance and health status while this is worst for clusters 6 and 7. All clusters show differences in dyspnea score, proportion of men/women, age, number of exacerbations and hospitalizations, proportion of patients using long-term oxygen and number of comorbidities.ConclusionBased on an integrated assessment of lung function variables, seven pathophysiological clusters can be identified in COPD patients. These clusters poorly predict functional performance and health status.

Profiling of Patients with COPD for Adequate Referral to Exercise-Based Care: The Dutch Model

“…These abnormalities can co-occur in different combinations, regardless of the degree of airflow limitation. Similar findings have been reported in patients with COPD who were under the care of Dutch pulmonologists [ 4 , 5 ].…”

“…Obviously, also the interactions between treatable traits can also add to the clinical complexity, which is more challenging to operationalize [ 43 ]. As the degree of clinical complexity cannot be derived confidently from the degree of lung function impairment [ 4 ], a thorough pre-PR assessment has to determine the correct treatment allocation (Table 3 ). Patients with ≤ 2 treatable traits will be referred for an outpatient PR program in secondary care (outpatient, 8–12 weeks, three sessions per week, which will include physiotherapy and one or two other health disciplines, like health promotion and dietician; Fig.…”

Association between patient-reported outcomes and exercise test outcomes in patients with COPD before and after pulmonary rehabilitation

“…Patients between the age of 40 and 85 years with a diagnosis of COPD according to GOLD guidelines [22] were eligible. The protocol and part of the results of the Chance-study have been published before [1,4,10,15,19,[23][24][25][26]. All patients gave written informed consent prior to inclusion in the study.…”

“…All patients gave written informed consent prior to inclusion in the study. [4]. Extensive pre-and post-PR assessments were performed, as described before [19].…”

Organizational aspects of pulmonary rehabilitation in chronic respiratory diseases

“…Historically, the degree of airflow limitation has been used to select patients with COPD for pulmonary rehabilitation . However, just using the degree of lung function impairment is not enough to truly understand the physical, emotional and social conditions of adults with a chronic respiratory disease . Indeed, dyspnoea, fatigue, dynamic hyperinflation, a reduced physical capacity, an impaired disease‐specific health status and social deprivation already occur in patients with a mild degree of airflow limitation .…”