Frequent cough is common in scleroderma patients with interstitial lung disease (SSc-ILD), and correlates with the presence and severity of other characteristics of scleroderma, including gastroesophageal reflux disease (GERD) and ILD, a report published in the journal Chest suggests.
The cough could also be a useful marker in assessing patients’ response to treatment in clinical trials for SSc-ILD, researchers wrote in the study, “Improved cough and cough-specific quality of life in patients treated for scleroderma-related interstitial lung disease (SSc-ILD): Results of Scleroderma Lung Study II.”
GERD is a chronic digestive disease in which stomach acid flows back into the esophagus, and ILD is characterized by progressive scarring of the lung tissue between the air sacs. According to the study, frequent cough declines as these conditions improve.
The team, led by Robert Elashoff, PhD, at the David Geffen School of Medicine at University of California, Los Angeles (UCLA), analyzed frequent cough in 142 SSc-ILD patients who were enrolled in the Scleroderma Lung Study II, a randomized clinical trial (NCT00883129) testing the effect of two immunosuppressant drugs, mycophenolate mofetil (MMF) and cyclophosphamide (CYC), for the treatment of ILD.
The researchers investigated the effect of frequent cough on the patients’ quality of life using the Leicester Cough Questionnaire, and evaluated the change in frequent cough in response to treatment. They also examined the relationship between GERD and frequent cough.
Results showed that 87 patients who had frequent cough at the start of the trial (61.3%) had significantly more shortness of breath and showed more extensive ILD. They also had lower diffusing capacity for carbon monoxide, one of the most clinically valuable tests of lung function, and reported more GERD-related symptoms compared to patients without frequent cough.
Cough-specific quality of life was modestly impaired in patients with frequent cough. After two years, frequent cough had declined by 44% in patients treated with CYC and 41% in those treated with MMF. The decline was significantly related to changes in the severity of GERD and ILD.
“Frequent cough occurs commonly in SSc-ILD, correlates with both the presence and severity of GERD and ILD at baseline and declines in parallel with improvements in both ILD and GERD during a 2-year course of therapy,” the team wrote, concluding that “frequent cough might serve as a useful surrogate marker of treatment response in SSc-ILD trials.”
Frequent cough is defined as a cough on several or most days of the week, and is based on the participants’ responses to the St. George’s Respiratory Questionnaire.