Pulmonary comorbidities associated with chronic obstructive pulmonary disease

Introduction
Chronic obstructive pulmonary disease (COPD) is characterized by a relatively irreversible airflow limitation caused by chronic inflammation, in most cases tobacco-related. The impact of COPD on morbidity and mortality at the single-patient level depends upon the severity of COPD symptoms and the existence of other types of systemic and/or pulmonary disease, also known as co-morbid conditions.

Materials and methods
This review examines the pulmonary diseases commonly associated with COPD, in terms of their prevalence, clinical features, pathogenic mechanisms, prognoses, and implications for management of COPD.

Results
The incidence and prevalence of various pulmonary diseases are significantly increased in patients with COPD. These conditions include symptomatic bronchiectasis, combined pulmonary fibrosis and emphysema, lung cancer, sleep-related respiratory disorders, and pulmonary embolism. Some of these concomitant respiratory diseases have an independent negative impact on the prognosis of COPD patients, and their presence has important implications for treatment of these patients.

Conclusions
Physicians treating patients with COPD need to be aware of these coexisting pulmonary diseases. All patients with COPD should be carefully evaluated to identify pulmonary comorbidities, since they not only influence the prognosis but also have an impact on disease management. The treatment of COPD is no longer restricted exclusively to inhaled therapy. The therapeutic approach to this disease is becoming increasingly multidimensional in view of the fact that successful management of comorbidities might positively affect the course of COPD itself.