Acute exacerbations in compulsory obstructive pulmonary disease (COPD) and its recurrences are still not accurately defined in the existing observation study literatures and there is an urgent need to reach a consensus on precise and objective definitions to improve the understanding of the natural history and burden of exacerbations in COPD patients. A systematic review conducted by Global Medical R&D, GlaxoSmithKline, Brentford, UK found that observational study literatures currently followed in the treatment methods do not clearly define subsequent acute exacerbations (AECOPD), particularly, when one AECOPD ends and another begins. The team said that they analyzed 47 studies to come to the conclusion that the use of standardised terminology and definitions may aid  comparability between studies which will potentially improve the understanding  in order to provide better treatment to patients.