Personalised medicine in exacerbations of COPD: the beginnings

Exacerbations of chronic obstructive pulmonary disease (COPD) are inflammatory events induced by infection [1]. Therefore, the use of antimicrobial and anti-inflammatory medications in exacerbations appears logical. However, the evidence that antibiotics and corticosteroids are beneficial in the treatment of exacerbations is relatively sparse, and only a meta-analytic approach has given us sufficient confidence in the use of these treatments [2, 3]. Placebo-controlled and observational studies in hospitalised patients with COPD exacerbations have shown the benefit of antibiotics and steroids [4–6]. This has led to current recommendations for treating all hospitalised exacerbations with both antibiotics and steroids. However, as we appreciate the heterogeneity of infection and inflammation in exacerbations, using the same treatment in all exacerbations does not appear appropriate. Bacterial infection causes approximately 50% of exacerbations; therefore, antibiotic use is probably unnecessary in the other 50% [1]. Eosinophilic inflammation is seen in a third of exacerbations, so corticosteroids may be of limited benefit in a substantial proportion of exacerbations [7]. In a hospitalised patient with a COPD exacerbation, the cost of antibiotics accounts for a small fraction of the total cost of care. However, everyone is well aware of the dangers of inappropriate and excessive antibiotic use with regards to selection of antibiotic resistant pathogens and adverse effects. Therefore, discriminating exacerbations that are bacterial in origin from those that are not would help us target antibiotic therapy. Sputum cultures lack the sensitivity, specificity and speed to be such a discriminatory tool. Biomarkers such as …