An Analysis of the Causes of Mortality and Co-Morbidities in Hospitalised Patients with Chronic Obstructive Pulmonary Disease

Introduction: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. Patients with COPD often suffer from various co-morbidities, such as cardiovascular disease, osteoporosis, cachexia and anaemia, which are a consequence of systemic inflammation. The co-morbidities of COPD are believed to be associated with a more severe course of the underlying disease and with a poorer prognosis. It is being disputed whether extrapulmonary co-morbidities or respiratory complications are the main cause of mortality in patients with COPD. The aim of the study was to analyse the causes of death and co-morbidities in COPD patients who had died during hospitalisation at the Department of Internal Medicine, Pneumonology and Allergy, Medical University of Warsaw, Poland, between 2004 and 2008. Material and methods: We analysed 266 consecutive medical records of COPD patients who had died during hospitalisation. They included 179 men (67%) and 87 women (33%). The mean age at death was 73 ± 8 years (women: 74 ± 9 years). Results: The causes of death in the analysed group of patients included: acute exacerbation of COPD (n = 81 [81%]; 49 men and 32 women), pneumonia (n = 67 [25%]; 50 men and 17 women), lung cancer (n = 50 [19%]; 32 men and 18 women), ischaemic heart disease (n = 20 [7%]; 15 men and 5 women), heart failure (n = 14 [5%]; 8 men and 6 women) and other causes (n = 34 [14%]). Most of the deaths from lung cancer were observed among younger patients (p = 0.002), while most of the deaths from pneumonia among older patients (p = 0.02). The most common co-morbidities in the study population included: chronic heart failure (n = 169), hypertension (n = 103), ischaemic heart disease (n = 102), type 2 diabetes mellitus (n = 55), renal failure (n = 43), benign prostatic hyperplasia (n = 36), lower limb atherosclerosis (n = 28), osteoporosis (n = 19) and anaemia (n = 14). Conclusions: Respiratory tract pathologies, such as acute exacerbation of COPD, pneumonia and lung cancer, were the most common causes of death in the study population, while cardiovascular disease and type 2 diabetes mellitus were the most common co-morbidities seen in these patients.