23 Exacerbations of COPD also have important consequences for health systems and societies. Nearly 60% of the global cost of COPD is associated with managing exacerbations, with the majority of the financial burden being associated with hospital treatment.24 This equates to costs in excess of A$550 million each year in Australia,25 over £800 million

Adriamycin cost in the United Kingdom26 and US$4.5 billion in the United States of America.27 One percent of all hospitalisations in Australia in the 2007–2008 financial year were for a primary diagnosis of COPD and the average length of stay was twice as long as the overall average length of stay for any condition, at 6.9 days compared to 3.3 days.25 In the USA, it is estimated that 20% of patients with COPD are readmitted within 30 days of discharge, with an increase in costs of 30% for subsequent admissions.27 General practice costs in the UK are doubled

for patients who experience two exacerbations per year compared to those who experience none.28 In the light of the costs of COPD exacerbations to individuals find more and the health system, there is a clear imperative to provide optimal, evidence-based management. A summary of interventions used in the management of AECOPD, along with the level of evidence that underpins their use, is provided in Figure 1. Short-acting inhaled beta-2 agonists are frequently prescribed during an acute exacerbation of COPD, as consensus indicates that they are of benefit.1 These are equally effective when administered via metered dose inhaler (with or without a spacer) compared to a nebuliser.1 Systemic corticosteroids are a mainstay of treatment. A systematic review including over 1000 patients found that corticosteroids halved the risk of return to hospital within 30 days (Peto OR 0.50, 95% CI 0.36 to 0.69).29 Those treated with corticosteroids also had a

shorter hospital stay (MD 1.22 days, 95% CI 0.18 to 2.26) and recovered their lung function more quickly. However, adverse events were more common in those treated with corticosteroids (Peto OR 2.33, 95% CI 1.60 to 3.40), particularly hypoglycaemia.29 Antibiotics provide a clear survival benefit for patients with a COPD exacerbation who are admitted to intensive care (Peto OR 0.21, 95% CI 0.06 to 0.72). Antibiotics also reduce length of hospital stay in this PDK4 group with severe exacerbations (mean reduction 9.6 days).30 However, the effects of antibiotics in mild and moderate exacerbations are less clear, with no mortality benefit and inconsistent effects across different outcomes. The GOLD standards suggest that antibiotics should be prescribed to patients who have all three cardinal signs of an exacerbation (increased dyspnoea, sputum volume, and sputum purulence), or to patients with two of the cardinal signs, if one of them is sputum purulence.1 Other pharmacological agents may be required for treatment of comorbidities, including diuretics and anticoagulants.