COPD patients who just have experienced an episode of acute exacerbations are at high risk of developing another attack. There has been only one randomized controlled study looking at the effect of out-patient PRP for patients immediately after an exacerbation. It has shown that PRP immediately after an exacerbation was safe and improved the exercise capacity and the quality of life at 3 months. However, the follow up duration of the study was short and thus the effect of rehabilitation on recurrent exacerbations and hospitalizations is not assessed and this information is important.