The World Health Organisation (WHO) was estimated that 65 million people have moderate o severe chronic obstructive pulmonary disease (COPD). WHO was stated that more than 3 million people died of COPD in 2005 that corresponds to 5% of all deaths globally. COPD is characterised by airflow obstruction. The airflow obstruction is usually progressive, not fully reversible and does not change markedly over several months. Airflow obstruction is defined as a reduced FEV1 (forced expiratory volume in 1 second) and a reduced FEV1/FVC ratio (where FVC is forced vital capacity), such that FEV1 is less than 80% predicted and FEV1/FVC is less than 0.7; the airflow obstruction is due to a combination of airway and parenchymal damage. COPD has been defined as an umbrella term covering a range of conditions including chronic bronchitis and emphysema. The literature review indicated that both depression and anxiety were significantly related to negative quality of life; surprisingly high prevalence of anxiety and depression in COPD patients.
