The common complications of chronic bronchitis include: 1. lung infections, which are more likely to occur after an acute attack than in the general population; 2. chronic pulmonary heart disease, which can occur in the later stages of COPD due to secondary elevation of pulmonary artery pressure, leading to right ventricular hypertrophy and thus chronic pulmonary heart disease. Now it is believed that COPD is an independent high-risk factor for coronary heart disease, so this disease itself can increase the risk of coronary heart disease; 3, at the same time, COPD, because of chronic pulmonary heart disease, after the reduction of activity, some patients are prone to lower limb vein thrombosis.