The Predicative Clinical Features Associated with Chronic Cough That Has a Single Underlying Cause

Few studies have investigated the usefulness of the clinical characteristics of cough in the diagnosis of chronic cough.

To evaluate the diagnostic value of clinical characteristics and concomitant symptoms of chronic cough in predicting its cause.

We recruited adult patients with chronic cough as a primary presenting symptom and identified those with a single underlying cause. Clinical features of cough were recorded with a custom-designed questionnaire and the relationships between clinical features and cause of cough were analyzed.

A total of 1162 patients with a single underlying cause were enrolled. Nocturnal cough alone was a predictor of cough variant asthma (odds ratio [OR], 2.037; 95% CI, 1.003-4.139) with high specificity (97.6%) and low sensitivity (8.1%). Heartburn (OR, 2.671; 95% CI, 1.544-4.620), belching (OR, 2.536; 95% CI, 1.620-3.971), and acid regurgitation (OR, 2.043; 95% CI, 1.299-3.212) indicated gastroesophageal reflux-related cough with high specificity (85.5%-94.9%) and low sensitivity (22.8%-40.7%). Cough after meals had a high specificity (91.2%) and a low sensitivity (24.8%) for gastroesophageal reflux-related cough. Postnasal dripping (OR, 2.317; 95% CI, 1.425-3.767) and history of sinusitis (OR, 4.137; 95% CI, 2.483-6.892) were indicators for upper airway cough syndrome with high specificity (80.8% and 90.2%, respectively). Rhinitis/sinusitis-related symptoms showed moderate sensitivity (72.9%); however, they showed mild specificity (46.1%) for upper airway cough syndrome.

Cough timing, several concomitant symptoms associated with gastroesophageal reflux or rhinitis/sinusitis, and medical history are useful to indicate common causes of chronic cough.