Other important diseases frequently coexist with COPD : the prevalence of heart failure varies from 7.2% to 20.9%, depression from 10% to 42%, and anxiety from 9.3% to 58%. There is an increased risk of diabetes (OR 2.04) and patients with severe COPD have a more than twofold increased risk of cardiovascular disease compared to patients
with normal lung function. A 2004 cross-sectional study using administrative health services databases indicated that 68.4% of COPD patients suffer from at least one chronic comorbidity and that about 16% COPD patients have two comorbid conditions.