Chronic obstructive pulmonary disease exacerbations and progression in relation to ambient air pollutants exposure.

Background: The information for the impact of air pollutants on the severity of chronic obstructive pulmonary disease (COPD) and hospital admissions in Bulgaria is scarce. The aim of the study is to assess the relationship between some ambient air pollution and exacerbations levels as well as hospital admissions of patients with COPD in Bulgaria.

Methods: A multi-center, prospective, one-year observational study was conducted among 426 COPD patients. Data from pollution monitoring are collected from the Executive Environment Agency (EEA).

Results: The results showed that the pollution with sulfur dioxide (SO) is less than limit concentrations recommended by the European Union and World Health Organization (WHO), while the pollution with PM exceeds limits values of WHO two times. The mean rate of exacerbations in selected towns are between 0.5-3, the number of exacerbations with hospitalization are between 0.2-1.8 and length of hospital stay is between 1-14 days.

Conclusions: The study confirms that air pollution leads to increased number of exacerbations and hospital stay. The patients with mild level of COPD have 0.86 exacerbations and 2.61 days in hospital per year, while in case of very severe COPD these values increase 4 times. Outside pollutions lead to worsening of the disease severity and hospitalizations due to a higher rate of COPD exacerbations.