Patients at risk of exacerbations

Several studies suggest a link between inflammation and exacerbations. It has been shown that COPD patients with frequent exacerbations have increased airway inflammation in the stable state¹ and that during an exacerbation there is an increase in airway inflammation.^1,2

Increased inflammatory markers in the stable state and during an exacerbation

A recent study investigated the sputum cell and cytokine characteristics in stable COPD and during an exacerbation.¹ It was found that patients with 3 or more exacerbations per year had higher sputum levels of IL-6 and IL-8 in the stable state than patients with 2 or less exacerbations per year. During an exacerbation the IL-6 levels were increased compared to stable condition while no statistically significant rises could be found for IL-8 levels. The authors conclude that baseline sputum cytokine levels could be used to predict the frequency of future exacerbations.

Figure 1: Association of interleukin levels and frequency of exacerbations in COPD patients ¹
Adapted from Bhowmik et al.¹

A significant rise in IL-6 levels during an exacerbation was confirmed and further detailed by a study from Perera et al (2007).² Another important finding of this study is that the magnitude of the increase in sputum IL-8 correlates to the exacerbation symptom recovery time.

Chronic cough and sputum indicates increased risk of exacerbations in COPD patients

A recent study showed that COPD patients with chronic cough and sputum production had increased numbers of exacerbations per year, moderate as well as severe exacerbations requiring hospitalisation.³ Frequent exacerbations of two or more per year occurred in 55% of patients with chronic cough and sputum, compared to 22% of patients without chronic cough and sputum.  

Figure 2: Association of chronic cough and sputum levels to exacerbation rate.³
Adapted from Burgel et al.³

Exacerbations drive disease progression⁴

The fact that patients with frequent exacerbations have an increased risk of disease progression emphasises the importance of preventing exacerbations.⁴

Expert opinion

References

1. Bhowmik A, Seemungal TA, Sapsford RJ, et al. Relation of sputum inflammatory markers to symptoms and lung function changes in COPD exacerbations. Thorax 2000;55:114-120.
2. Perera WR, Hurst JR, Wilkinson TM, et al. Inflammatory changes, recovery and recurrence at COPD exacerbation. Eur Respir J 2007;29:527-534.
3. Burgel PR, Nesme-Meyer P, Chanez P, et al. Cough and sputum production are associated with frequent exacerbations and hospitalizations in COPD subjects. Chest 2009;135:975-982.
4. Wedzicha JA & Seemungal TA. COPD exacerbations: defining their cause and prevention. Lancet 2007;370:786-796.
5. Donaldson GC, Seemungal TA, Bhowmik A, et al. Relationship between exacerbation frequency and lung function decline in chronic obstructive pulmonary disease. Thorax 2002;57:847-852.
6. Seemungal TA, Donaldson GC, Paul EA, et al. Effect of exacerbation on quality of life in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1998;151:1418-1422.
7. Groenewegen KH, Schols AM & Wouters EF. Mortality and mortality-related factors after hospitalization for acute exacerbation of COPD. Chest 2003;124:459-467.
8. Soler-Cataluna JJ, Martinez-Garcia MA, Roman Sanchez P, et al. Severe acute exacerbations and mortality in patients with chronic obstructive pulmonary disease. Thorax 2005;60:925-931.