The distribution characteristics of etiology of chronic cough in Lanzhou

Abstract

To explore the distribution characteristics of etiology and clinical feature of chronic cough in Lanzhou. Based on the guidelines of the diagnostic process of chronic cough in China, data of medical history and physical examinations were collected, and chest X-ray, pulmonary function plus airway hyperresponsiveness, induced sputum eosinophils, sinus X-ray or CT, 24 h esophageal pH monitoring, chest high-resolution CT and bronchoscopy were performed accordingly for outpatients with chronic cough. The cause of chronic cough was identified by the test results and treatment response. The results were compared with those reported previously in other areas of China. A total of 173 patients with completed data were collected, including 90 males and 83 females.The causes were as follows: 45 cases (26.01%) of cough variant asthma, 35 (20.23%) upper airway cough syndrome, 20 (11.56%) allergic cough, 17 (9.83%) chronic pharyngitis, 14 (8.09%) gastroesophageal reflux, 14 (8.09%)postinfectious, 13 (7.51%) eosinophilic bronchitis, 8 (4.62%) chronic bronchitis, 4 (2.31%) cough associated with ACEI, 3 (1.73%) bronchial tuberculosis, 2 (1.16%) pulmonary fibrosis and bronchiectasis repectively. The causes of the remaining 14 patients (8.09%)were unknown. The causes of chronic cough were identified in 159 patients (91.91%), of which 141 (88.68%) with a single cause and 18(11.32%)with more than 2 etiological factors.The percentage of cough variant asthma in our series was significantly higher than that reported in Guangzhou (13.6%, χ(2)=5.60, P=0.018, P<0.05), but lower than that reported in Shenyang (39.4%, χ(2)=7.91, P=0, 004, P<0.01). The percentage of allergic cough was higher than that reported in Beijing (3.3%, χ(2)=6.66, P=0.010, P<0.05), and that of eosinophilic bronchitis was lower than those reported in Guangzhou(22.4%, χ(2)=22.38, P=0.000, P<0.01) and Shenyang (12.5%, χ(2)=8.09, P=0.005, P<0.01). The percentage of esophageal reflux cough was lower than that reported in Beijing (20.3%, χ(2)=9.40, P=0.002, P<0.01) but higher than that reported in Shenyang (1.9%, χ(2)=3.98, P=0.036, P<0.05). In Lanzhou, cough variant asthma, upper airway cough syndrome, allergic cough, chronic pharyngitis and gastroesophageal reflux were the main causes of chronic cough, and the etiological distribution was different from Guangzhou, Beijing, Shenyang and other areas.