The effect of smoking on the severity, and mechanisms of acute exacerbations of chronic obstructive pulmonary disease (COPD)

COPD (Chronic Obstructive Pulmonary Disease) worldwide has a prevalence of<br/>10% in men and 8.5% in women. Exacerbations of COPD account for<br/>approximately 10% of all acute medical admissions. Projected prevalence<br/>figures suggest that by 2020 COPD will be the third leading cause of mortality<br/>worldwide thus imposing a significant burden on healthcare resources in the<br/>future. Acute exacerbations are not only responsible for a decline in the<br/>patient’s quality of life, but have a major socioeconomic impact. Following a<br/>pilot study that showed current smokers recover lung function much more<br/>slowly from their exacerbation than ex smokers, I initiated a properly powered<br/>prospective study to investigate the difference between the two groups.<br/>A total of 58 patients admitted with acute infectious exacerbations of COPD<br/>were recruited to the study to determine the effect of smoking status on their<br/>exacerbation. Throughout the admission lung function was measured. Sputum<br/>was cultured for bacteria, and PCR used to detect viral infection. Blood and<br/>sputum cells were analyzed by flow cytometry. Serum was collected for CRP<br/>levels.<br/><br/>Ex-smokers recovered significantly more quickly than current smokers in all<br/>spirometric parameters (P&lt;0.01), and were discharged sooner (mean 3.08 vs<br/>5.59 days, P&lt;0.001). Sputum culture was positive for more pathogenic bacteria<br/>in current smokers, especially H. influenzae, which was associated with a<br/>significantly higher CRP rise (p&lt;0.05) than any other organism. CD8+ T cells<br/>predominated in the sputum of ex-smokers while CD4+ T cells were the<br/>dominant cell type in current smokers (p&lt;0.01).<br/>Current smoking is a risk factor for more severe exacerbations, delayed<br/>recovery and prolonged hospitalization. This may result from a variety of factors<br/>including bacterial, immune mediated responses and systemic inflammation.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2008

Author dc:creator

• Bourne, Simon Charles

Advisors dc:contributor.advisor

• Djukanovic, Ratko
• Marshall, Ben