Predictors of improvement of Dyspnoea, Exercice Capacity, and Quality of Life in Chronic Obstructive Pulmonary Disease patients undergoing an outpatient Pulmonary Rehabilitation

Marie-Cécile FOURNIERa, Thomas LESUFFLEURa, Alexandre TOUVRONb, Michel CABILLICc, Arnaud CAVAILLESd, Jean-Benoit HARDOUINe, Yann PEREONf, Arnaud CHAMBELLANg

a Institut de Santé Publique, d’Epidémiologie et de Développement (ISPED), Université Bordeaux Segalen, Bordeaux - FRANCE, b UFR STAPS, Université de Nantes, Nantes - FRANCE, c Hôpital Nord Laennec, CHU de Nantes, Nantes - FRANCE, d Service de Pneumologie, CHU de Nantes, Nantes - FRANCE, e UPRES EA 4275, Biostatistiques, UFR Médecine, Université de Nantes, Nantes - FRANCE, f Explorations Fonctionnelles, CHU de Nantes, Nantes - FRANCE, g l'institut du thorax, Inserm UMR1087, Explorations Fonctionnelles, CHU de Nantes, Nantes - FRANCE

Purpose: Whether Pulmonary rehabilitation represents the optimal way to improve COPD patients, providing inclusion criterias of success still remains challenging.

Subjects and Methods: Ninety four stable COPD patients attended for outpatient pulmonary rehabilitation (PR) program between 2006 and 2011. After complete assessment, they underwent a 3 week’s physical training and therapeutic education at the hospital with two sessions a week. This was followed by 20 cycloergometer sessions managed by the patient’s physiotherapist at the rhythm of 3 courses a week. The patients were evaluated at 6 months and every year. The logistic regression was used to identify the independent predictors of success to PR, defined by the MCID for dyspnoea (modified Medical Research Council dyspnoea score), exercise capacity on the 6 minute walk distance (6MWD), and the health-related quality of life (HRQoL) on the S George’s Respiratory Questionnaire (SGRQ).

Results: The predictors identified were different for the three dimensions. The phenotype of patients who improve the MMRC scale displayed a higher level of dyspnoea at baseline (OR=6.14, 2.73 to 13.79 CI 95%, p<0.0001), there FFMI was not low (OR=8.32, 2.14 to 32.31 CI 95%, p=0.002), and they could reach a higher VO2max during the CPET (OR=1.10, 1.05 to 1.15 CI 95%, p<0.0001). For the improvement of the 6MWD, the only variable identified was patients who did not live alone (OR=9.19, 1.16 to 73.02 CI 95%, p<0.05). The phenotype of patients who improve the SGRQ score included patients with a higher FEV1 at baseline (OR=1.06, 1.01 to 1.11 CI 95%, p=0.02), a higher level of dyspnoea at baseline (OR=2.12, 1.05 to 4.28 CI 95%, p<0.05), a worse HRQoL at baseline (OR=1.11, 1.04 to 1.18 CI 95%, p=0.002), they present less systemic inflammation (OR=4.07, 1.15 to 14.39 CI 95%, p=0.03) and were more prone to have a 6MWD>350 m (OR=9.72, 1.92 to 49.24 CI 95%, p=0.006).

Conclusion: As predictors of improvement differ for every dimension, they should be evaluated separately to better define the components of success to PR. This could help to individualize the goals of PR for a given patient.

Keywords : COPD, symptoms, exercise, six minute walk test, handicap