The Quality of Life in Patients with Diffuse and Limited Systemic Sclerosis

Systemic Sclerosis (SSc) is a rare, autoimmune, connective tissue disease. It has potentially severe physical and psychological impacts on the individual. SSc has two sub-types, diffuse cutaneous systemic sclerosis (dcSSc) and limited cutaneous systemic sclerosis (IcSSc). This study had three aims: to develop a framework to describe and understand the impact of SSc on Quality of Life (QoL) in SSc; develop a measure of QoL in SSc; and test the hypothesis that levels of quality of life will differ between disease sub-type. To achieve the study aims a mixture of qualitative and quantitative methods were used. In order to develop the descriptive framework of QoL in SSc, qualitative data was gathered from 31 interviews and a focus group of people with SSc. The data was analysed using thematic analysis and the themes used to form the descriptive framework. The descriptive framework of SSc QoL consisted of thirty themes which form four overarching themes of Emotion, Physical adaptation, Impact on/with others, and Self. To develop the SSc QoL scale, potential items were identified through a process of item selection from the qualitative data. Together with comparator measures, a 90 item draft SSc QoL was posted to 336 patients randomised from the National Scleroderma Database (NSD), with a return rate of 61 % (203). Items not fitting the Rasch model of item response theory were deleted: 39 items were retained. The 39-item questionnaire was administered to a second population of 369 SSc patients randomised from the NSD. 159 were returned and respondents received a second copy, 117 of these were returned within four weeks (74% of first returns). Further Rasch analysis resulted in a 29 item SSc QoL measure. The SSc QoL (29) showed reliability of 0.764 over two-time points. Non- parametric testing showed that sub-type of disease had no significant impact of levels of QoL (p, 0.836). However, Structural Equation Modelling revealed an indirect influence of disease sub-type on QoL, this being related to disability associated with disease sub-type.