A study conducted in Finland and published in BMC Pulmonary Medicine looked at the five-year outcomes of a group of patients with a chronic cough.
A cough is an important symptom and one of the most common reasons people seek medical attention. It can strongly affect quality of life, especially persistent chronic cough, which is defined as a cough lasting longer than eight weeks. Understanding the long-term prognosis for patients with a chronic cough and the reasons for different outcomes would be a valuable guide to its management, but few studies have examined this area.
Researchers in Finland looked at the five-year outcomes in a group of patients with a chronic cough. They recently reported their findings in BMC Pulmonary Medicine. The study recruited a total of 89 patients, some of whom had taken part in previous studies on cough and others who were recruited through newspaper advertisements.
Patients had a detailed initial assessment which included a clinical examination, symptom questionnaire, cough questionnaire, skin prick tests (to test for allergies), measurements of lung function, and cough provocation tests. Following the assessment, all subjects were offered the option to visit a respiratory physician for treatment. These consultations were separate from the study and cough treatment was not standardized.
Five years after the initial assessment, the subjects were contacted by mail with several questionnaires. These questionnaires asked about the continuation of the cough, smoking, current medications, and allergen exposures. The questionnaire also asked patients about any other illnesses, in particular, those known to be related to a chronic cough, such as esophageal reflux disease, asthma, and chronic rhinitis.
Sixty-eight of the initial 89 subjects (76%) responded to the follow-up letter. Continuing chronic cough was present in 31 (46%) of these patients, and 32 patients (47%) reported continuing impairment in cough-related quality of life. There was a large overlap in these two groups, although some patients had improved quality of life despite the persistence of a chronic cough, while others had continuing impairment of cough-related quality of life, despite no longer having a chronic cough.
Chronic Rhinitis, Esophageal Reflux Disease, and Obesity among Common Factors
Continuing chronic cough was associated with the presence of chronic rhinitis or esophageal reflux disease, and increased responsiveness to some cough provocation stimuli at initial assessment. Continuing impairment in cough-related quality of life was associated with being overweight and having a high number of background disorders which could cause a chronic cough.
Almost half of subjects with chronic cough still suffered from this disorder after five years. Some patients may experience an impaired quality of life even if the cough is no longer regular. The researchers state that it is important to identify and manage all background disorders that may contribute to a chronic cough, not just the most obvious. Strong responsiveness to cough provocation tests may indicate dysfunction of the cough reflex and a poor long-term prognosis. The authors of the study also note that obesity seems to be strongly associated with poor prognosis in chronic cough and the effects of weight loss on chronic cough could be a promising option for further evaluation.
Written by Julie McShane, Medical Writer
Reference: Koskela H, Latti A & Purokivi M. Long-term prognosis of chronic cough: a prospective, observational cohort study. BMC Pulmonary Medicine 92017)17:146. DOI: 10.1186/s12890-017-0496-1.