A new study has revealed that both obese and slim patients with chronic obstructive pulmonary disease (COPD) can benefit from pulmonary rehabilitation.
The University Hospitals of Leicester in the UK conducted the research.
Neil Greening, who led the study, said: "Like the healthy population, the prevalence of obesity is increasing in those with COPD. There is evidence that obesity may lower exercise capacity but at the same time appears to confer a survival advantage, which is known as the obesity paradox.
"Pulmonary rehabilitation is effective in improving exercise capacity and health status in COPD but it is unclear whether these benefits accrue in patients with extreme obesity. We wanted to compare the outcomes of a pulmonary rehabilitation program in patients with obesity of varying severity and normal weight subjects."
To compare the effects of pulmonary rehabilitation between obese and non-obese patients, Dr. Greening and colleagues recruited patients with clinical and spirometric COPD and classified them according to their level of obesity, from normal weight to extreme obesity. The patients underwent pulmonary rehabilitation at a single center in the UK. The improvements in their exercise performance and endurance, as well as their health status (chronic respiratory questionnaire) and baseline characteristics were assessed.
Greening said: "We found that obese people with COPD are more disabled in terms of exercise capacity, despite having less severe airflow obstruction (the measure used to quantify severity of COPD). However, they do just as well with rehab including those with extreme obesity. There is no difference between obesity subgroups in the proportion of patients achieving a clinically significant improvement in the incremental shuttle walk test."
The experts found no difference in training effects between normal weight and extremely obese patients.
Greening said: "Patients with COPD, irrespective of body mass, improve following a pulmonary rehabilitation program. Therefore extremely obese patients with COPD should still be considered for enrolment."
"As medical professionals, we know that obesity is linked with medical complications such as diabetes and heart disease, so how it can lead to a survival advantage in other diseases such as COPD or chronic kidney disease is puzzling. The reasons for this are currently unknown and further research is needed."
He concluded: "We are planning a study to look at the underlying mechanisms of skeletal muscle dysfunction and obesity in COPD. Rather than a larger multi-centre study looking at epidemiology, we are trying to understand why obesity affects patients with COPD in the way it does."
The results of their study will be presented at the ATS 2010 International Conference in New Orleans.