Abstract
Introduction: 10% of asthmatics have refractory disease. Cluster analysis has identified that BMI is a factor in defining phenotypes of severe asthma [1]. Obesity antedates asthma diagnosis [2], suggesting that obesity has a pathophysiological role.
Last year we reported the outcome of 115 patients with severe, treatment refractory asthma (ATS, 2000). This study looks at data from 374 patients from 4 UK centres, collected as part of the National Registry for dedicated UK Difficult Asthma Services.
Methods: Patients were divided into three groups by BMI: 18.5 to 24.99, 25 to 29.99 (overweight), and ≥30 (obese).
Results: The table below highlights demographic data, lung function, steroid use and bone density between groups.
Table 1. Obesity and severe asthma
Conclusion: Severe asthmatics are more likely to be female although this does not appear to correlate to BMI. Raised BMI is associated with more GORD, greater use of PPI's, increased KCO, but a reduction in aspirin sensitivity, and appears to be protective against osteoporosis at the neck of femur.
References:
1. Moore W, et al. Identification of asthma phenotypes using cluster analysis in the severe asthma research program. AJCCM 2009 epub ahead of print.
2. Shore SA. Obesity and asthma: cause for concern. Current Opinion in Pharmacology 2006;6:230-236.
- © 2011 ERS
