The Assessment of Health-Related Quality of Life in Scleroderma-Interstitial Lung Disease

Pulmonary involvement is the most common cause of mortality and disability in patients with systemic sclerosis and it significantly affects the quality of life in these patients. Therefore, early diagnosis and treatment of pulmonary involvement seems necessary in patients with SSc. In this study, we aimed to assess the health-related quality of life (HRQoL) in patients with Scleroderma-Interstitial Lung Disease (SSc-ILD) and its relationship with pulmonary function parameters. Considering the inclusion and exclusion criteria, 25 patients with SSc-ILD were enrolled in this cross-sectional study from April 2012 to June 2013. Full tests of lung function, including body plethysmography and diffusing capacity of the lungs for carbon monoxide (DLCO), 6-minute walk distance (6MWD), and pulse oximetry were performed. The HRQoL was assessed using St. George’s and CAT questionnaires; also, dyspnea was evaluated for all the patients, using modified medical research council (MMRC) scale. Afterwards, the relationship between the total scores of HRQoL questionnaires and the severity of lung disease was analyzed, based on the recorded variables. The mean age of the patients was 40.36±9.50 years and the mean duration of the disease was 7.16±4.50 years. A statistically significant inverse correlation was observed between 6MWD (r=-0.50, P=0.01), DLCO (r=-0.67, P<0.001), and CAT total score. In addition, there was a statistically significant negative association between CAT score and total lung capacity (r=-0.46, P=0.01). Finally, a significant direct relationship was observed between the total scores of CAT and St. George’s questionnaires (r=0.75, P<0.001). The results of this study showed that CAT questionnaire is a suitable tool for assessing the quality of life in SSc patients; moreover, it is significantly related to the factors associated with pulmonary function. Therefore, the CAT questionnaire may be used to track pulmonary function in SSc patients.